U.S. patent application number 14/386470 was filed with the patent office on 2015-02-19 for hb-egf inhibitor derived from the r domain of diphtheria toxin for the treatment of diseases associated with the activation of the hb-egf/egfr pathway.
This patent application is currently assigned to COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENE ALT. The applicant listed for this patent is COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENE ALT. Invention is credited to Daniel Gillet, Bernard Maillere, Sylvain Pichard, Alain Sanson, Benoit Villiers.
Application Number | 20150051146 14/386470 |
Document ID | / |
Family ID | 48237170 |
Filed Date | 2015-02-19 |
United States Patent
Application |
20150051146 |
Kind Code |
A1 |
Gillet; Daniel ; et
al. |
February 19, 2015 |
HB-EGF INHIBITOR DERIVED FROM THE R DOMAIN OF DIPHTHERIA TOXIN FOR
THE TREATMENT OF DISEASES ASSOCIATED WITH THE ACTIVATION OF THE
HB-EGF/EGFR PATHWAY
Abstract
A ligand recombinant protein inhibiting HB-EGF (Heparin-Binding
Epidermal Growth Factor like), from the R domain of diphtheria
toxin, which can be used for the treatment and diagnosis of
diseases involving the activation of the HB-EGF/EGFR pathway.
Inventors: |
Gillet; Daniel; (Antony,
FR) ; Villiers; Benoit; (Roiffe, FR) ;
Pichard; Sylvain; (Leuville Sur Orge, FR) ; Maillere;
Bernard; (Versailles, FR) ; Sanson; Alain;
(Gometz Le Chatel, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENE ALT |
Paris |
|
FR |
|
|
Assignee: |
COMMISSARIAT A L'ENERGIE ATOMIQUE
ET AUX ENE ALT
Paris
FR
|
Family ID: |
48237170 |
Appl. No.: |
14/386470 |
Filed: |
March 19, 2013 |
PCT Filed: |
March 19, 2013 |
PCT NO: |
PCT/IB2013/052173 |
371 Date: |
September 19, 2014 |
Current U.S.
Class: |
514/6.9 ;
435/252.33; 435/254.2; 435/320.1; 435/325; 435/348; 435/7.21;
435/7.24; 436/501; 514/44R; 514/9.6; 530/350; 536/23.7 |
Current CPC
Class: |
A61P 13/12 20180101;
C07K 14/34 20130101; C12Y 204/02036 20130101; A61P 9/10 20180101;
C12N 9/1077 20130101; A61P 21/00 20180101; A61P 9/00 20180101; A61K
38/164 20130101; A61P 35/00 20180101; A61P 27/02 20180101; A61P
9/12 20180101; G01N 33/74 20130101; A61K 48/00 20130101; A61K 38/00
20130101 |
Class at
Publication: |
514/6.9 ;
530/350; 536/23.7; 435/320.1; 435/252.33; 514/9.6; 436/501;
514/44.R; 435/325; 435/348; 435/254.2; 435/7.21; 435/7.24 |
International
Class: |
C07K 14/34 20060101
C07K014/34; G01N 33/74 20060101 G01N033/74; A61K 38/16 20060101
A61K038/16; C12N 9/10 20060101 C12N009/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 20, 2012 |
FR |
1252497 |
Claims
1. A recombinant protein comprising an amino acid sequence having
at least 70% similarity with residues 380 to 535 of the amino acid
sequence SEQ ID NO: 1 which correspond to a R domain of diphtheria
toxin, wherein the amino acid sequence comprises a substitution of
at least one residue selected from the group consisting of Y380,
P382, Q387, P388 and L390 of the R domain with another amino acid
selected from the group consisting of: S, T, N, C, Y, Q, R, K, H, D
and E, the amino acid sequence is devoid, at the N- or C-terminal
end of the R domain, of the sequence of the T domain or of the C
domain and of the T domain of diphtheria toxin, and of the sequence
of a protein or of a protein domain capable of improving stability
or purification of the R domain, and the recombinant protein is a
ligand inhibiting HB-EGF.
2. The protein as claimed in claim 1, comprising at least two
substitutions selected from the group consisting of Y380K, Y380E,
P382T, Q387E, Q387K, P388T, L390T and L390N.
3. The protein as claimed in claim 2, comprising at least the
substitutions Y380K and L390T or Y380K and Q387E.
4. The protein as claimed in claim 3, comprising at least the
substitutions Y380K, Q387E and L390T.
5. The protein as claimed in claim 1, further comprising a
substitution A395T.
6. The protein as claimed in claim 1, further comprising at least
one substitution of F389Y and G510A.
7. The protein as claimed in claim 1, further comprising at least
one substitution selected from the group consisting of: N399K,
V452T, T517E, V483Q, H492E, S494K, T436H and E497D.
8. The protein as claimed in claim 7, comprising substitutions
N399K, V452T, T517E, V483Q, H492E and S494K.
9. The protein as claimed in claim 1, comprising one of amino acid
sequences SEQ ID NOs: 2 to 9.
10. The protein as claimed in claim 1, which is labeled with a
detectable tracer.
11. The protein as claimed in claim 10, wherein the detectable
tracer is a radioactive isotope or a fluorophore.
12. An isolated polynucleotide encoding the recombinant protein as
claimed in claim 1.
13. The polynucleotide as claimed in claim 12, comprising one of
nucleotide sequences SEQ ID NOs: 10, 12 or 14.
14. A recombinant cloning and/or expression vector comprising the
polynucleotide as claimed in claim 12.
15. A cell modified with the recombinant cloning and/or expression
vector as claimed in claim 14.
16. A pharmaceutical composition, comprising at least one
recombinant protein as claimed in claim 1, and a pharmaceutically
acceptable vehicle.
17. A method for treating a disease associated with activation of
HB-EGF/EGFR pathway in a subject in need thereof, the method
comprising: administering the recombinant protein as claimed in
claim 1 to the subject, wherein the disease is selected from the
group consisting of: rapidly progressive glomerulonephritis,
cancers, vasospasm associated with cerebral contusions, cardiac
hypertrophy, smooth muscle cell hyperplasia, pulmonary
hypertension, diabetic retinopathies and arterial restenosis.
18. A method for an in vitro diagnosis of a disease associated with
activation of HB-EGF/EGFR pathway, the method comprising: obtaining
a biological sample from a subject, contacting the protein as
claimed in claim 10 with the biological sample, thereby forming a
complex between the protein and HB-EGF or pro-HB-EGF, detecting the
presence of the complex, and diagnosing the subject as having the
disease where the presence of the complex is detected, wherein the
disease is selected from the group consisting of: rapidly
progressive glomerulonephritis, cancers, vasospasm associated with
cerebral contusions, cardiac hypertrophy, smooth muscle cell
hyperplasia, pulmonary hypertension, diabetic retinopathies and
arterial restenosis.
19. A pharmaceutical composition, comprising the recombinant
cloning and/or expression vector as claimed in claim 14, and a
pharmaceutically acceptable vehicle.
20. A method for treating a disease associated with activation of
HB-EGF/EGFR pathway, the method comprising: administering the
recombinant cloning and/or expression vector as claimed in claim 14
to a recipient in need thereof, wherein the disease is selected
from the group consisting of: rapidly progressive
glomerulonephritis, cancers, vasospasm associated with cerebral
contusions, cardiac hypertrophy, smooth muscle cell hyperplasia,
pulmonary hypertension, diabetic retinopathies and arterial
restenosis.
Description
[0001] The present invention relates to a ligand recombinant
protein inhibiting HB-EGF (Heparin-Binding Epidermal Growth
Factor-like growth factor), derived from the R domain of diphtheria
toxin, of use for the treatment and diagnosis of diseases involving
the activation of the HB-EGF/EGFR pathway.
[0002] HB-EGF is a growth factor expressed at the surface of the
cells of the organism in the form of a precursor membrane protein,
pro-HB-EGF, which is the natural diphtheria toxin receptor.
[0003] Diphtheria toxin (DT) is an exotoxin of 535 amino acids (SEQ
ID NO: 1) composed of a fragment A (N-terminal) and of a fragment B
(C-terminal). Fragment A comprises the catalytic domain (C or
DTA/DT-A; residues 1 to 193) and fragment B comprises the
translocation domain (T; N-terminal; residues 202 to 378), and the
cell receptor-binding domain (R or DTR; C-terminal; residues
379-386 to 535). DT binds to the surface of cells via the binding
of its R domain to pro-HB-EGF; after activation of DT by
proteolytic cleavage between fragments A and B, the T domain allows
translocation of fragment A into the cytoplasm. Once in the
cytoplasm, the catalytic domain carried by fragment A blocks
protein synthesis by inactivating the EF2 elongation factor, thus
causing cell death. The study of natural or synthetic mutants of DT
has shown that the binding of DT to the pro-HB-EGF receptor is
abolished by the substitution of residue S508 (S508F) or of
residues of the loop of the region K516-F530 of DTR (K516A, K516E,
F530A, F530S and S525F), but not by the deletion of the 4
C-terminal residues (residues E532-S535; Shen et al., J. Biol.
Chem., 1994, 269, 29077-29084). In addition, the natural mutant of
DT comprising the G52E mutation, called CRM197, has a greatly
reduced catalytic activity (Giannini et al., N.A.R., 1984, 12,
4063-4069).
[0004] During inflammatory processes involving HB-EGF, the
pro-HB-EGF membrane protein is cleaved by a protease and HB-EGF is
released from the cell surface, in the form of a secreted protein.
It then binds in an autocrine or paracrine manner to the ErbB1
(HER1 or EGFR) and ErbB4 (HER4) subunits of the EGF receptor family
(EGFR family or EGFR), expressed in virtually all the tissues of
the organism. There are at least ten EGFR ligands in addition to
HB-EGF, namely EGF, TGF-alpha, amphiregulin, betacellulin, epigen,
epiregulin and neuregulins -1, -2, -3 and -4. It is the local
context which determines the stimulation of EGFR by one or the
other of these ligands.
[0005] The activation of the HB-EGF/EGFR pathway which is
associated with increased expression of pro-HB-EGF and/or the
release of HB-EGF leads to deleterious cell proliferation
responsible for numerous pathological conditions:
[0006] rapidly progressive glomerulonephritis (RPGN) during which
the proliferation of the glomerular renal cells (podocytes) results
in kidney destruction (Feng et al., J. Clin. Invest., 2000, 105,
341-350; Bollee et al., Nat. Med., 2011, 17, 1242-1250),
[0007] cancers, including ovarian cancer, endometrial cancer,
breast cancer, uterine cancer (uterine adenocarcinoma), bladder
cancer, stomach cancer, skin cancer (malignant melanoma), brain
cancer (glioblastoma) and lung cancer (Yotsumoto et al., Biochem
Biophys Res Commun, 2008, 365, 555-561; Miyamoto et al., Adv. Exp.
Med. Biol., 2008, 622, 281-295; Miyamoto et al., Anticancer Res.,
2009, 29, 823-830; Fu et al., Proc. Natl. Acad. Sci. U S A, 1999,
96, 5716-5721; Tsujioka et al., Anticancer. Res., 2010, 30,
3107-3112),
[0008] vasospasm associated with cerebral contusions (Chansel et
al., FASEB J., 2006, 20, 1936-1938),
[0009] cardiac hypertrophy (Asakura et al., Nat. Med., 2002, 8,
35-40; Hamaoka et al., J. Biochem., 2010, 148, 55-69),
[0010] smooth muscle cell hyperplasia (Miyagawa et al., J. Clin.
Invest., 1995, 95, 404-411; Hamaoka et al., J. Biochem., 2010, 148,
55-69),
[0011] pulmonary hypertension (Powell et al., Am. J. Pathol., 1993,
143, 784-793; Hamaoka et al., J. Biochem., 2010, 148, 55-69),
[0012] diabetic retinopathies, and
[0013] arterial restinosis.
[0014] Because of its involvement in an increasing number of
diseases, HB-EGF represents a therapeutic target. There are
currently two types of molecules available for blocking the action
of HB-EGF on the EGFR, EGFR inhibitors and HB-EGF inhibitors. These
molecules which are potentially usable for treating pathological
conditions involving EGFR activation by HB-EGF (HB-EGF/EGFR
pathway) have, however, a certain number of major drawbacks.
[0015] EGFR Inhibitors
[0016] Two types of EGFR inhibitors could theoretically be used to
block EGFR stimulation by HB-EGF: reversible tyrosine kinase
inhibitors which act on the EGFR, such as erlotinib, and antibodies
directed against the EGFR, such as cetuximab (Ciardiello and
Tortora, N. Engl. J. Med., 358, 1160-1174; WO 2008/053270).
[0017] However, these molecules which act on the tyrosine kinase of
the EGFR (small molecules) or on the EGFR itself (monoclonal
antibodies) are not specific for the HB-EGF/EGFR pathway, given
that they block the activation of the EGFR irrespective of the
origin of its stimulation, independently of the ligand activating
it and irrespective of this ligand. Because of their lack of
specificity, EGFR inhibitors produce significant side effects. By
way of example, mention may be made of the following side effects
reported, respectively, for erlotinib and cetuximab: neutropenia,
thrombocytopenia, anemia, edema, nausea, vomiting, headaches,
pruritus and musculoskeletal pain; fever, shivering, urticaria,
pruritus, skin rash, hypotension, bronchospasm, dyspnea, edema,
confusion, anaphylactic shock and cardiac arrest.
[0018] Furthermore, antibodies are too big (150 kDa) to reach their
target in the case of RPGN given that the EGFR stimulated by HB-EGF
is expressed by the podocytes in the kidney glomeruli and that the
glomerular filtration threshold is approximately 68 kDa. Likewise,
the penetration of antibodies into solid tumors is limited owing to
their size.
[0019] HB-EGF Inhibitors
[0020] In mice, knockout of the pro-HB-EGF gene prevents the
triggering of induced RPGN (Bollee et al., Nat. Med., 2011, 17,
1242-1250), thus justifying the advantage of developing a ligand
inhibiting HB-EGF and pro-HB-EGF for the treatment of pathological
conditions involving the activation of the HB-EGF/EGFR pathway.
[0021] There are currently two types of HB-EGF inhibitors
potentially usable for blocking EGFR stimulation by HB-EGF:
antibodies directed against HB-EGF (WO 2009/040134; WO 2011/21381;
WO 2009/72628; EP 2221374; EP 2281001; EP 2093237; EP2078731; EP
2039704; WO 2008/053270) and CRM197 (U.S. Pat. No. 7,700,546; US
2006/0270600).
[0022] The antibodies directed against HB-EGF are more specific
than the EGFR inhibitors given that they block only the activation
of the HB-EGF/EGFR pathway, but they have the same drawbacks as the
anti-EGFR antibodies, linked to their excessive size.
[0023] CRM197 is a natural ligand of HB-EGF capable of blocking its
binding to the EGFR. It is currently used in clinical trials to
block HB-EGF in order to combat ovarian cancer (Koshikawa et al.,
Cancer Sci., 2011, 102, 111-116; Tsujioka et al., Anticancer Res.,
2011, 31, 2461-2465).
[0024] However, CRM197 has drawbacks in terms of residual toxicity,
size, affinity, immunogenicity and antigenicity.
[0025] The residual toxicity of CRM197 is 10.sup.6 times lower than
that of the wild-type diphtheria toxin (Kageyama et al., J.
Biochem., 2007, 142, 95-104). This is, however, not insignificant
since the wild-type toxin is extremely powerful with a lethal dose
50 (LD50) of 5 pM in primate cell culture. CRM197 is therefore
toxic at micromolar (.mu.M) doses. This can present a risk if it is
administered to humans at high dose (Kageyama et al., J. Biochem.,
2007, 142, 95-104).
[0026] CRM197 has a molecular weight of 58 kDa, passing the
glomerular filtration threshold with difficulty. It cannot
therefore be used to treat RPGN or other pathological conditions
such as solid tumors, where tissue penetration is an important
factor for therapeutic efficacy.
[0027] CRM197 has a medium affinity for HB-EGF (Kd=27 nM; Brooke et
al., Biochem. Biophys. Res. Commun., 1998, 248, 297-302). This
affinity is lower than that of a good therapeutic antibody.
[0028] CRM197 is very immunogenic. It differs from diphtheria toxin
only by one residue (G52E). It therefore carries all of the CD4 T
epitopes of diphtheria toxin, or almost, if the mutation affects a
T epitope. As it happens, western populations are vaccinated
against diphtheria toxin. Treating patients with CRM197 amounts to
giving a vaccination booster. As early as the first injection,
CRM197 can cause the reactivation of memory CD4 T cells and can
restimulate the production of circulating antibodies. A few days
after the first administration of CRM197, these antibodies should
neutralize the protein and make the treatment ineffective.
[0029] CRM197 is very antigenic since it has virtually all the B
epitopes of diphtheria toxin. Since the western population is
vaccinated against diphtheria toxin, a significant fraction of
individuals have circulating antibodies capable of neutralizing
CRM197 as early as the first administration. This imposes the use
of massives doses of CRM197 in order to obtain a therapeutic
effect, while considerably increasing the risks of side effects
(toxicity, anaphylactic shock, etc.)
[0030] Consequently, there is a real need to have new HB-EGF
inhibitors which have a smaller size, a better affinity for HB-EGF,
and a reduced antigenicity, immunogenicity and toxicity, compared
with CRM197.
[0031] Up until now, it has not been possible to produce the
isolated DTR domain, directly, in recombinant form, with a high
yield, and without using detergents or chaotropic or denaturing
agents to extract the recombinant protein from the transformed
cells.
[0032] Indeed, in order to stabilize the structure of the isolated
DTR domain, and to improve the extraction and purification of this
domain from the transformed bacteria, it is essential to fuse the
DTR domain to a protein (glutathione-S-transferase, GST) or to a
protein domain (ZZ domain derived from S. aureus protein A (Lobeck
et al., Infect. Immun., 1998, 66, 418-423; Shen et al., J. Biol.
Chem., 1994, 269, 29077-29084). In addition, mutants of the loop of
region 516-530 of DTR have been produced using the GST-DTR fusion;
these DTR mutants are incapable of binding to the pro-HB-EGF
receptor (Shen et al., 1994).
[0033] In the abovementioned two cases, the recombinant protein
produced in E. coli is not an isolated DTR domain, but a GST-DTR or
ZZ-DTR fusion protein. In the case of the GST-DTR fusion protein,
the production yields are mediocre and it is essential to use a
detergent (1% Triton X-100) to extract the fusion protein from the
transformed bacteria. Furthermore, in order to produce a
therapeutic protein, the fusion partner must be removed, thereby
making the production process much more complex and even further
reducing yields.
[0034] The inventors have constructed mutants of the isolated DTR
domain, devoid of fusion-partner sequences. These mutants of the
isolated DTR domain are expressed directly and in a large amount in
the form of a soluble recombinant DTR protein of small size
(approximately 17500 Da) with affinity for pro-HB-EGF and HB-EGF.
These DTR mutants have been modified to produce improved
recombinant DTR proteins which, surprisingly, have both a reduced
antigenicity and immunogenicity and a considerably increased
affinity, compared with CRM197.
[0035] Consequently, a subject of the present invention is a
recombinant protein comprising an amino acid sequence having at
least 70% similarity with residues 380 to 535 of the amino acid
sequence SEQ ID NO: 1 which correspond to the R domain of
diphtheria toxin, said sequence comprising the substitution of at
least one, preferably at least two, of the residues Y380, P382,
Q387, P388 and/or L390 of said R domain with another amino acid
selected from the group consisting of: S, T, N, C, Y, Q, R, K, H, D
and E, and said sequence being devoid, at the N- or C-terminal end
of said R domain, of the sequence of the T domain or of the C
domain and of the T domain of diphtheria toxin and of the sequence
of a protein or of a protein domain capable of improving the
stability or the purification of said R domain, and said
recombinant protein being a ligand inhibiting HB-EGF.
[0036] The invention provides a therapeutic recombinant protein
that is a ligand of HB-EGF and of pro-HB-EGF, which has the
following advantages:
[0037] it has a greatly increased solubility compared with the
wild-type form DTR.sub.WT. The substitution of at least one,
preferably at least two, of the residues Y380, P382, Q387, P388
and/or L390 with a different hydrophilic, polar or charged amino
acid residue as defined above makes it possible to considerably
increase the solubility of the DTR protein in aqueous solution.
Thus, the recombinant protein according to the invention can be
extracted from the host cells and purified without using detergents
or chaotropic or denaturing agents. By comparison, the wild-type
DTR protein (DTR.sub.WT) produced in the same expression system is
insoluble and not solubilized using detergents compatible with
therapeutic use. The DTR.sub.WT protein is solubilized in the
presence of 0.5% of sarkosyl or sodium dodecyl sulfate, which are
detergents that are incompatible with therapeutic use at these
concentrations;
[0038] it is much easier to produce in recombinant form than
DTR.sub.WT. It is produced directly, without using a fusion partner
for improving the stability or the purification of the R domain. It
is produced in E. coli according to standard fermentation
procedures, in a folded soluble form, and in a large amount after
final purification (several tens of mg/l of culture under
nonoptimized laboratory conditions);
[0039] it has an affinity for HB-EGF and pro-HB-EGF which is at
least 10 times greater than that of CRM197. Surprisingly, although
the wild-type DTR protein (DTR.sub.WT) has an affinity for HB-EGF
and pro-HB-EGF which is 2-fold lower than that of CRM197, the
mutant DTR proteins according to the invention have an affinity for
HB-EGF and pro-HB-EGF that is considerably higher than that of
CRM197; the proteins called DTR1, DTR3 and DTR8 have, respectively,
an affinity which is 60, 300 and 1400 times higher than that of
CRM197. This means that DTR8 could be used at doses much lower than
CRM197 for the same therapeutic effect. As a result, the risks of
side effects, linked in general to the existence of low-affinity
binding with other proteins or ligands of the organism, are
therefore considerably reduced by comparison with CRM197. These
interactions are eliminated by using low doses, of the order of one
pM, which should be the case for DTR8;
[0040] it has a reduced immunogenicity compared with CRM197 and
with DTR.sub.WT. Ten of the 26 T epitopes identified in DTR.sub.WT
have been deleted from the DTR8 protein by site-directed
mutagenesis, including 7 among 9 immunodominant epitopes;
[0041] it has a greatly reduced antigenicity compared with CRM197
and with DTR.sub.WT. The sera of individuals vaccinated against
diphtheria toxin preferentially recognize the catalytic domain of
said toxin. This domain is present in the CRM197 molecule and
absent from the mutated DTR protein according to the invention.
Moreover, the mutated DTR protein according to the invention is not
as well recognized as DTR.sub.WT by the antibodies of vaccinated
subjects which recognize DTR.sub.WT;
[0042] it blocks a pathway of EGFR (ErbB1 and ErbB4) activation by
HB-EFG much more specifically than the commercial EGFR inhibitors
(therapeutic antibodies and small molecules), as a result
presenting potentially much less risk of side effects;
[0043] it is small in size; the proteins of SEQ ID NOs: 2 to 9 have
a sequence of 158 amino acids and an MW of approximately 17 500 Da,
i.e. a size 3.4 times smaller than that of CRM197 and 8.8 times
smaller than that of the anti-HB-EGF antibodies currently used in
clinical protocols for blocking the HB-EGF pathway. As a result of
its small size, the recombinant protein according to the invention
is more effective in the treatment of pathological conditions
associated with the activation of the HB-EGF pathway, in particular
RPGN or ovarian cancer, since it diffuses more readily in the
tissues, in particular tumors, and is capable of penetrating into
kidney glomeruli.
[0044] In addition, because of its high affinity for HB-EGF and
pro-HB-EGF, the protein according to the invention can also be used
for the diagnosis of diseases involving the activation of the
HB-EGF/EGFR pathway.
[0045] Definitions
[0046] In the present application, the term "DTR" or "DTR domain"
is intended to mean the R domain of diphtheria toxin which
corresponds to residues 380-385 to 531-535 of the amino acid
sequence of wild-type diphtheria toxin (SEQ ID NO: 1).
[0047] The expression "DTR protein" denotes a recombinant protein
comprising an isolated DTR domain, i.e. which is devoid, at its N-
or C-terminal end, of the sequence of the T domain or of the C
domain and of the T domain of diphtheria toxin and of the sequence
of a protein or of a protein domain capable of improving the
stability or the purification of said R domain. In addition, the
purification of the R domain includes the extraction and the
purification of said domain, given that it is produced in the form
of a recombinant protein.
[0048] The recombinant protein according to the invention which
comprises at least one, preferably at least two, substitution(s) as
defined above is denoted mutant DTR protein, mutated DTR protein or
DTR.sub.n protein where n is an integer, as opposed to the
wild-type DTR recombinant protein (DTR.sub.WT) which does not
comprise this substitution.
[0049] The amino acids are denoted using the one-letter code.
[0050] The similarity of an amino acid sequence compared with a
reference sequence is assessed according to the percentage of amino
acid residues which are identical or which differ via conservative
substitutions, when the two sequences are aligned so as to obtain
the maximum correspondence between them. When only the identical
residues are taken into account and the percentage of identical
residues is determined, reference is then made to the identity of
said amino acid sequence relative to the reference sequence. For
the purpose of the present invention, the expression "conservative
substitution in the amino acid sequence of a protein" is intended
to mean the substitution of one amino acid with another natural or
synthetic amino acid which has similar chemical or physical
properties (size, charge or polarity), which do not have a
deleterious effect on the biological activity of the protein. Thus,
two amino acid sequences of a protein are similar when they differ
from one another by the substitution of an amino acid, or the
deletion and/or insertion of an amino acid or of a small number of
amino acids (less than 5) at positions which do not have a
deleterious effect on the biological activity of said protein. The
percentage similarity or identity can be calculated by those
skilled in the art using sequence comparison software, such as, for
example, that of the BLAST software series (Altschul et al., NAR,
1997, 25, 3389-3402). The BLAST programs are implemented using the
default parameters, on a comparison window consisting of residues
380 to 535 of the amino acid sequence SEQ ID NO: 1.
[0051] Unless otherwise indicated, the term "HB-EGF" denotes both
the membrane precursor (pro-HB-EGF) and the secreted form of
HB-EGF.
[0052] The activity of ligand inhibiting HB-EGF refers to the
capacity to bind to pro-HB-EGF and to HB-EGF and to the inhibition
of various measurable biological phenomena, such as:
[0053] the inhibition of the toxic effect of diphtheria toxin on
human or simian cells such as Vero cells,
[0054] the inhibition of the proliferating activity of HB-EGF on
cells expressing the ErbB1 and/or ErbB4 subtypes of the EGFR and
the growth of which is HB-EGF-dependent, such as a murine lymphoid
cell line Ba/F3 transfected with the EGFR gene.
[0055] The recombinant protein according to the invention comprises
an isolated DTR domain, devoid, at its N- or C-terminal end, of one
of the following sequences: (1) the sequence of the T domain or of
the C domain and of the T domain of diphtheria toxin, and (2) the
sequence of a fusion partner capable of improving the stability of
the DTR domain, such as the sequence of gluthatione-S-transferase
(GST), or capable of improving the extraction and the purification
of the DTR domain from the transformed bacteria, such as the
sequence of an immunoglobulin binding domain derived from S. aureus
protein A (ZZ domain).
[0056] The recombinant protein according to the invention generally
comprises an isolated DTR domain which extends from residues 380 to
535 of the sequence SEQ ID NO: 1 and comprises the substitution of
one or more, preferably at least two, of the residues Y380, P382,
Q387, P388 and/or L390 with a hydrophilic, polar or charged amino
acid residue as defined above. However, it may also comprise a
slightly shorter isolated DTR domain, the N-terminal end of which
is in position 381 to 385 and the C-terminal end of which is in
position 531 to 534 of the sequence SEQ ID NO:1. When the
N-terminal sequence of DTR is in position 381 or 382, the
recombinant protein according to the invention comprises the
substitution of at least one of the residues P382, Q387, P388
and/or L390. When the N-terminal sequence of DTR is in position
383, 384 or 385, the recombinant protein according to the invention
comprises the substitution of at least one of the residues Q387,
P388 and/or L390.
[0057] The recombinant protein according to the invention
optionally comprises a methionine (M) at its N-ter end and/or
additional sequences at the N- and/or C-terminal of the DTR domain.
Indeed, the precursor of said recombinant protein comprises an
N-terminal methionine which can be cleaved by post-translational
modifications, such that it is absent in the mature recombinant
protein.
[0058] For therapeutic applications, the protein according to the
invention consists successively of: (1) a sequence of 1 to 10 amino
acids, preferably 1 to 5 amino acids, preferably of 1 or 2 amino
acids, the sequence of the precursor and optionally that of the
mature protein beginning with a methionine (M), for example an MG
sequence, and (2) a mutated DTR domain as defined above. Such a
therapeutic protein has a small size, of approximately 145 to 200
amino acids, preferably of approximately 145 to 175 amino acids,
preferably of approximately 160 amino acids.
[0059] For diagnostic applications, the protein according to the
invention is labeled, in particular with a peptide tracer which can
be detected by measuring an appropriate signal. The peptide tracer
is in particular a tag recognized by an antibody, a fluorescent
protein, or a peptide which binds at least one Technetium 99 atom.
The label is in the N-ter or C-ter position of the protein, i.e.
fused, directly or by means of a peptide spacer, respectively to
the N-ter or C-ter end of the DTR domain. Such a protein has a size
of approximately 145 to 500 amino acids, preferably of
approximately 145 to 300 amino acids, preferably of approximately
145 to 200 amino acids.
[0060] The invention encompasses the modified recombinant proteins
derived from the previous one by the introduction of any
modification at the level of one or more amino acid residue(s), of
the peptide bond or of the ends of the recombinant protein,
provided that said modified protein retains good affinity and an
inhibitory activity with respect to HB-EGF and to pro-HB-EGF. These
modifications which are introduced into the proteins by
conventional methods known to those skilled in the art include, in
a nonlimiting manner: the substitution of an amino acid with a
synthetic amino acid (D amino acid or amino acid analog); the
addition of a chemical group (lipid, oligosaccharide or
polysaccharide) at the level of a reactive function, in particular
of the side chain R; the modification of the peptide bond
(--CO--NH--), in particular via a bond of the retro or
retro-inverso type (--NH--CO--) or a bond other than the peptide
bond; cyclization; fusion (by genetic engineering) to a peptide or
a protein of interest or coupling (via chemical bonding) to a
molecule of interest, in particular a labeling agent or tracer
which is detectable by measuring a signal.
[0061] According to one advantageous embodiment of said protein, it
comprises at least one substitution selected from the group
consisting of Y380K, Y380E, P382T, Q387E, Q387K, P388T, L390T and
L390N.
[0062] According to one advantageous arrangement, said
substitution(s) is (are) selected from the group consisting of
Y380K, Y380E, Q387K, Q387E and L390T. Preferably, said
substitution(s) is (are) selected from the group consisting of
Y380K, Q387E and L390T.
[0063] According to another advantageous arrangement, said protein
comprises at least two or three of said substitutions.
[0064] Preferably, said protein comprises at least the
substitutions Y380K and L390T, Y380K and Q387E, Y380E and L390T or
Y380E and Q387K, preferably at least the substitutions Y380K and
L390T or Y380K and Q387E. For example, said protein comprises one
of the following substitution combinations: Y380K and L390T; Y380K,
Q387E and L390T; Y380K, Q387E, P388T and L390T; Y380K, Q387E, P382T
and L390T; Y380E, Q387K, P382T and L390T. Preferably, it is a
protein which comprises or consists of one of the sequences SEQ ID
NOs: 2 to 6.
[0065] Preferably, said protein comprises at least the
substitutions Y380K and L390T. For example, said protein comprises
or consists of one of the sequences SEQ ID NOs: 2 to 5.
[0066] Even more preferably, said protein comprises the
substitutions Y380K, Q387E and L390T. For example, said protein
comprises or consists of one of the sequences SEQ ID NOs: 3 to 5,
preferably the sequence SEQ ID NO: 3.
[0067] According to another advantageous embodiment of said
protein, it comprises in addition the substitution A395T. The
addition of the substitution produces an additional increase in the
yield of soluble protein. Preferably, said protein comprises the
sequence SEQ ID NO: 7; this protein called DTR1 comprises the
substitutions Y380K, Q387E, L390T and A395T. The HB-EGF-binding
affinity of the DTR1 protein is increased by a factor 60 compared
with that of CRM197 and by a factor of 130 compared with that of
the DTR.sub.WT protein solubilized using 0.5% of sarkosyl
detergent.
[0068] According to yet another advantageous embodiment of said
protein, it also comprises at least one of the substitutions F389Y
and/or G510A. The addition of one of these substitutions increases
the HB-EGF-binding affinity of the DTR protein. In addition, the
combination of the two substitutions produces an additional
increase in the HB-EGF-binding affinity, compared with the increase
obtained with a single substitution. Preferably, said protein
comprises or consists of the sequence SEQ ID NO: 8; this protein
called DTR3 comprises the substitutions Y380K, Q387E, L390T, A395T,
F389Y and G510A. The affinity of the DTR3 protein for HB-EGF is
increased by a factor of 5 compared with that of DTR1 and by a
factor of 300 compared with that of CRM197.
[0069] According to another advantageous embodiment of said
protein, it also comprises at least one substitution selected from
the group consisting of N399K, V452T, T517E, V483Q, H492E, S494K,
T436H and E497D. Said protein advantageously comprises at least 3,
preferably at least 5, of said substitutions.
[0070] Preferably, said protein comprises the substitutions N399K,
V452T, T517E, V483Q, H492E and S494K. These mutations have made it
possible to delete 10 of the 26 CD4 T epitopes identified in
DTR.sub.WT. Among these 10 epitopes are 7 of the 9 epitopes
predicted as being immunodominant epitopes of DTR.sub.WT. The
capacity of the resulting protein to induce an immune response of
CD4 type, i.e. an antibody-producing response, is thus considerably
reduced compared with that of DTR.sub.WT. Notably and unexpectedly,
the addition of the six mutations intended to reduce the
immunogenicity of DTR has contributed to increasing its affinity
for HB-EGF.
[0071] Preferably, said protein comprises or consists of the
sequence SEQ ID NO: 9; this protein called DTR8 comprises the
substitutions Y380K, Q387E, L390T, A395T, F389Y, G510A, N399K,
V452T, T517E, V483Q, H492E and S494K. It has a molecular weight of
17458 Da.
[0072] The affinity of the DTR8 protein for HB-EGF is increased by
a factor of 3 compared with that of DTR3 and by a factor of 1400
compared with that of CRM197. In addition, DTR8 is at least 300
times more effective than CRM197 in terms of binding to secreted
HB-EGF and inhibiting the HB-EGF/EGFR pathway.
[0073] The antigenicity of the DTR8 protein is greatly reduced
compared with that of CRM197. Indeed, most of the antibodies
present in adults vaccinated against DT (obligatory vaccination)
are directed against the catalytic domain of DT. Surprisingly and
unexpectedly, the antigenicity of the DTR8 protein is reduced
compared with that of DTR1, and therefore of DTR.sub.WT.
[0074] The protein according to the invention may comprise
additional substitutions, in particular of residues located at the
surface of the DTR domain, so as to even further reduce its
antigenicity.
[0075] According to another advantageous embodiment of said
protein, it comprises an amino acid sequence which has at least 80%
similarity with residues 380 to 535 of the sequence SEQ ID NO: 1,
preferably at least 85%, preferably at least 90%. According to one
advantageous arrangement of said protein, it comprises an amino
acid sequence which has at least 70% identity, preferably at least
80%, 85% or 90% identity, with residues 380 to 535 of the sequence
SEQ ID NO: 1.
[0076] According to another advantageous embodiment of said
protein, it is labeled with a detectable tracer. The means and the
techniques for labeling proteins are well known to those skilled in
the art and include radioactive, magnetic or fluorescent labeling
which can be carried out directly or indirectly. The direct
labeling agents are, in particular, radioactive isotopes such as
tritium (.sup.3H), iodine (.sup.125I) and technetium (.sup.99mTc)
or luminescent (radioluminescent, chemoluminescent, bioluminescent,
fluorescent or phosphorescent) compounds such as fluorophores, for
instance, in a nonlimiting manner, AlexaFluor.RTM., FITC and
Cyanine 3, and fluorescent proteins such as GFP and its
derivatives. The indirect labeling agents include, in particular,
enzymes and epitope tags recognized by a specific antibody. The
labeling is in particular carried out by: (1) grafting a
fluorophore onto a reactional group such as a reactional amine of a
lysine residue, (2) incorporating a reactional group (free
cysteine) by chemical synthesis or recombinant production, then
using this group to graft a fluorophore, (3) directly incorporating
a fluorophore, in the N- or C-terminal position, by chemical
synthesis, (4) directly incorporating a fluorescent protein or an
enzyme by production of a fusion protein. Such labeled proteins are
in particular used as a reagent for the diagnosis, in vitro or in
vivo (by imaging), of diseases associated with the activation of
the HB-EGF/EGFR pathway or as a tool for studying this activation
pathway. The DTR protein can be labeled directly by covalent
coupling of technetium (.sup.99mTc) or of a fluorescent tracer; the
fluorescent tracer is in particular coupled to one of the lysine
residues of the DTR protein.
[0077] The recombinant protein of the present invention can be
produced by means of a method in which an expression vector
comprising a polynucleotide encoding said protein, functionally
linked to the regulatory elements allowing its expression in the
chosen host, is transferred into a host cell which is placed in
culture under conditions which allow the expression of said
protein. The protein produced is then recovered and purified. The
purification methods used are known to those skilled in the art.
The recombinant protein obtained can be purified from cell lysates
or extracts, or from the culture medium supernatant, by means of
methods used individually or in combination, such as fractionation,
chromatography methods, or immunoaffinity techniques using specific
monoclonal or polyclonal antibodies. The recombinant protein
obtained is soluble.
[0078] A subject of the present invention is also an isolated
polynucleotide encoding said recombinant protein. Said
polynucleotide advantageously comprises a coding sequence optimized
for expression in the host cell in which the protein of the
invention is produced. Preferably, said polynucleotide comprises
the sequence SEQ ID NO: 10, 12 or 14 which is optimized for
expression in E. coli and encodes respectively the DTR1, DTR3 and
DTR8 recombinant protein. The polynucleotide of the invention is a
DNA or an RNA prepared using the conventional chemical synthesis or
molecular biology methods known to those skilled in the art.
[0079] A subject of the present invention is also a recombinant
cloning and/or expression vector comprising said polynucleotide.
Preferably, said vector is an expression vector comprising said
polynucleotide functionally linked to the regulatory sequences
which allow the expression of the protein of the invention in the
cell host used for the production of said protein (promoter,
enhancer, initiation codon (ATG), codon stop, transcription
termination signal). The vector, which may be a replicating or
integrating vector, in particular a plasmid or a viral vector, is
prepared according to the methods commonly used by those skilled in
the art.
[0080] A subject of the present invention is also a host cell
transiently or stably modified with a recombinant vector as defined
above. These cells may be obtained by introducing a recombinant
vector as defined above into a eukaryotic or prokaryotic host cell
using standard methods known to those skilled in the art, such as
electroporation. Examples of host cells include, in particular,
mammalian cells, insect cells, bacteria such as E. coli and
yeasts.
[0081] A subject of the present invention is also a pharmaceutical
composition comprising at least one recombinant protein or one
recombinant expression vector as defined above and a
pharmaceutically acceptable vehicle.
[0082] The pharmaceutical composition comprises an effective dose
of protein or of vector for obtaining a therapeutic effect on
diseases associated with activation of the HB-EGF/EGFR pathway, as
defined above. Generally, a therapeutically effective amount
ranging from approximately 0.1 .mu.g to approximately 100 mg,
preferably from 10 .mu.g to 10 mg, can be administered to human
adults. The pharmaceutically acceptable vehicles are those
conventionally used. The composition is in a galenical form
suitable for a chosen administration: injectable sterile solution,
powder, tablets, gel capsules, suspension, syrup or suppositories,
which are prepared according to standard protocols. The
administration may be subcutaneous, intramuscular, intravenous,
intradermal, intraperitoneal, oral, sublingual, rectal, vaginal,
intranasal, by inhalation or by transdermal application.
[0083] The modes of administration, the dosage regimens and the
galenical forms of the pharmaceutical compositions according to the
invention may be determined in the usual way by those skilled in
the art, in particular according to the criteria generally taken
into account for establishing a therapeutic treatment suitable for
a patient (generally a human individual and optionally a non-human
mammal), for instance age, body weight, seriousness of the
patient's general condition, tolerance of the treatment, and side
effects observed.
[0084] A subject of the present invention is also a recombinant
protein as defined above, as a medicament.
[0085] The present invention also relates to a recombinant protein
as defined above, for use in the treatment of diseases associated
with activation of the HB-EGF/EGFR pathway.
[0086] A subject of the present invention is also the use of a
recombinant protein as defined above, for preparing a medicament
intended for the treatment of diseases associated with activation
of the HB-EGF/EGFR pathway.
[0087] A subject of the present invention is also a method for
treating diseases associated with activation of the HB-EGF/EGFR
pathway, comprising the administration of a pharmaceutical
composition as defined above, to an individual. The administration
is carried out according to an appropriate mode and an appropriate
rate as defined above.
[0088] Preferably, said diseases are selected from the group
consisting of: rapidly progressive glomerulonephritis (RPGN),
cancers, in particular ovarian cancer, endometrial cancer, breast
cancer, uterine cancer (uterine adenocarcinoma), bladder cancer,
stomach cancer, skin cancer (malignant melanoma), brain cancer
(glioblastoma) and lung cancer, vasospasm associated with cerebral
contusions, cardiac hypertrophy, smooth muscle cell hyperplasia,
pulmonary hypertension, diabetic retinopathies and arterial
restenosis.
[0089] A subject of the present invention is also the use of a
labeled protein as defined above, for the in vitro or in vivo
diagnosis of a disease associated with activation of the
HB-EGF/EGFR pathway.
[0090] The invention also relates to a method for the in vitro
diagnosis of a disease associated with activation of the
HB-EGF/EGFR pathway, which comprises bringing a biological sample
into contact with a labeled protein as defined above, under
conditions which allow the formation of a specific complex between
said labeled protein and HB-EGF and/or pro-HB-EGF, and detecting
said labeled protein/HB-EGF complexes, by any appropriate
means.
[0091] The biological sample is in particular a biopsy sample
(kidney, tumor, smooth muscle, heart, lung, vessels, retina), serum
sample or urine sample.
[0092] A subject of the present invention is also the use of a
labeled protein as defined above, for the detection, in vitro or in
vivo, of HB-EGF.
[0093] A subject of the present invention is also a method for
detecting HB-EGF, in vitro and in vivo, comprising at least the
following steps:
[0094] bringing cells to be analyzed into contact with a labeled
protein as defined above, and
[0095] detecting the labeled cells and/or extracellular medium by
any appropriate means.
[0096] This method makes it possible to determine the tissue
expression profile of HB-EGF under physiological or pathological
conditions or in response to an endogenous or exogenous stimulus.
The detection of HB-EGF, in vivo, in the body of a mammal (cell
imaging), in particular in real time, comprises a prior step of
administering said protein to said mammal (parenteral injection,
oral administration). The detection of HB-EGF in vivo in humans can
be used to diagnose a disease associated with activation of the
HB-EGF/EGFR pathway.
[0097] The labeling of the cells and of the extracellular medium
containing HB-EGF is in particular fluorescent or radioactive
labeling, or magnetic labeling, detectable by any technique known
to those skilled in the art (fluorescence microscopy, flow
cytometry, gammagraphy, magnetic resonance imaging).
[0098] A subject of the invention is also a kit for carrying out
the diagnostic or detection methods as defined above, comprising a
labeled protein as defined above.
[0099] In addition to the above arrangements, the invention also
comprises other arrangements, which will emerge from the following
description, which refers to exemplary embodiments of the subject
matter of the present invention, with reference to the appended
drawings in which:
[0100] FIG. 1 represents the mutations (A) and the analysis (B) of
the soluble and insoluble fractions of the 5 clones selected by
screening of the R1 library in order to produce a DTR protein which
is more soluble than DTR.sub.WT. All the clones are soluble; the
best clone is the 1 D6 clone;
[0101] FIG. 2 shows the effects of the A395T and N399D mutations on
the solubility of the DTR protein produced by the 1D6 clone
(denoted here G1). The best clone contains the A395T mutation;
[0102] FIG. 3 represents: (A) the inhibition of the toxic effect of
increasing doses of diphtheria toxin on Vero cells by increasing
doses of DTR1 and (B) the Schild regression for evaluating the Kd
of DTR1 for HB-EGF according to the equation log
(EC.sub.50-1)=K.sub.d log (B) where EC.sub.50 is the concentration
of diphtheria toxin which gives 50% toxicity and B is the
concentration of inhibitor DTR1;
[0103] FIG. 4 represents the inhibition of the toxic effect of
diphtheria toxin at the concentration of 10.sup.-11 M on Vero cells
by each DTR1 mutant (denoted here G2) at a concentration of
10.sup.-9 M;
[0104] FIG. 5 represents: (A) the inhibition of the toxic effect of
increasing doses of diphtheria toxin on Vero cells by increasing
doses of DTR8 and (B): the Schild regression for evaluating the Kd
of DTR8 for HB-EGF according to the equation log
(EC.sub.50-1)=K.sub.d log (B) where EC.sub.50 is the concentration
of diphtheria toxin which gives 50% toxicity and B is the
concentration of inhibitor DTR8;
[0105] FIG. 6 represents the inhibition of the proliferative effect
of increasing doses of HB-EGF on Ba/F3 cells expressing the EGFR
and the growth of which is HB-EGF-dependent, by increasing doses of
DTR8 (A) and of CRM197 (B);
[0106] FIG. 7 represents the recognition of the CRM197, diphtheria
toxin domain C (C) and domain T (T), DTR1 and DTR8 proteins by the
antibodies present in the serum of 20 healthy donors. The titer is
defined by the serum dilution which gives a fluorescence signal of
5000 arbitrary units in the ELISA assay, after subtraction of the
background noise. A titer .ltoreq.20 corresponds to the background
noise and therefore to the absence of measurable antibody binding.
A titer of 30 was arbitrarily set for distinguishing weak antibody
responses from medium or strong responses.
EXAMPLE 1
Materials and Methods
1) Cloning of Genetic Sequences, Expression and Purification of the
DTR.sub.WT Protein and of its Mutants
[0107] The genetic sequence encoding the DTR domain of diphtheria
toxin, covering the sequence Y380-S535 of the native toxin, was the
starting point for this study. All the genetic sequences were
synthesized, after optimization for expression in E. coli, by the
company Geneart according to the previously determined protein
sequences. These sequences were cloned into the pET28a(+) vector
(Novagen) at the NcoI and SalI restriction sites. The presence of
the NcoI site generates the non-native codons M and G corresponding
to the N-terminal end of the recombinant protein. The sequence SEQ
ID NO: 16 is the optimized nucleotide sequence which encodes the
wild-type DTR protein (DTR.sub.WT) of 158 amino acids, which
consists of the residues M and G followed by the residues Y380 to
S535 of native diphtheria toxin. The optimized nucleotide sequences
encoding the mutant and soluble forms of the DTR protein derive
from the sequence SEQ ID NO: 16 by replacement of each codon to be
mutated with an optimized codon encoding the mutated amino acid, as
indicated in Table I:
TABLE-US-00001 TABLE I List of the optimized codons chosen for the
DTR mutations Wild- Optimized type mutated Mutation codon codon
Y380K tac aaa Y380E tac gaa P382T ccg acg Q387E cag gag Q387K cag
aag P388T ccg acg F389Y ttt tat L390T ctg acc L390N ctg aac H391K
cat aaa A395T gcg acc N399D aac gat N399K aac aaa V401Q gtg cag
L427Q ctg cag L427N ctg aac L427S ctg agc T436K acc aaa T436H acc
cat V452T gtg acg I457D att gat I457E att gaa R460T cgt acc A463T
gcg acc A463S gcg agc A463E gcg gaa A463D gcg gat A463G gcg ggc
Y478T tat acc V483D gtg gat V483E gtg gaa V483H gtg cat V483Q gtg
cag A490G gcg ggc H492E cat gaa S494K agc aaa S496K agc aaa E497D
gaa gat G510A ggc gcg G510M ggc atg G510Q ggc cag G510S ggc agc
Q515E cag gaa T517D acc gat T517E acc gaa T521R acc cgc K522R aaa
cgc
[0108] The expression of the DTR.sub.WT protein was carried out in
the Escherichia coli BL21(DE3) bacterium in Terrific Broth medium
in the presence of 50 .mu.g/ml of kanamycin at 37.degree. C. The
induction of the protein is carried out by adding 1 mM of isopropyl
.beta.-D-1-thiogalactopyranoside (IPTG). The bacteria were
recovered by centrifugation at 5000 g for 45 min and lyzed in a
buffer of 20 mM sodium phosphate, 500 mM NaCl, 0.25 mM
phenylmethylsulfonyl fluoride (PMSF), lysozyme (0.25 mg/ml), pH 8,
by passing them through a Cell Disrupter (Constant Systems). The
inclusion bodies containing the protein were solubilized in a
solution containing 8 M of urea in 0.1 M Tris-HCl, pH 8. The
protein is purified by cation exchange chromatography on a 5 ml
HiTrap.TM. SP column (GE Health Care Life Sciences) according to a
buffer gradient between 8 M of urea in 0.1 M Tris-HCl, pH 8, and 8
M of urea, 1 M NaCl in 0.1 M Tris-HCl, pH 8, and then folded by
means of dialysis in 2 steps, firstly against a buffer of 20 mM
Tris-HCl, 50 mM NaCl, 1 mM cysteine/8 mM cystine, 0.5% sarkosyl, pH
8, and then against a buffer of 20 mM Tris-HCl, 50 mM NaCl, 0.5%
sarkosyl, pH 8.
[0109] The expression of the mutant and soluble forms of the DTR
protein was carried out in the Escherichia coli BL21(DE3) bacterium
in 2YT medium in the presence of 50 .mu.g/mi of kanamycin. After 2
h 20 min of culture at 37.degree. C., the induction of the protein
is carried out by adding 1 mM of IPTG. Then, after 4 h 30 min at
30.degree. C., the bacteria were recovered by centrifugation at
5000 g for 30 min and lyzed in a buffer of 20 mM sodium phosphate,
0.25 mM PMSF, 2 mM MgCl.sub.2, supplemented with benzonase (6.25
U/ml), pH 7.8, in a Cell Disrupter (Constant Systems). The protein,
which is soluble in the lysis mixture, was purified by cation
exchange chromatography on a 5 ml HiTrap.TM. SP column according to
a gradient between 20 mM sodium phosphate, pH 7.8, and 20 mM sodium
phosphate, 1 M NaCl, pH 7.8 (GE), and stored at -20.degree. C. in a
buffer of 20 mM sodium phosphate, 500 mM NaCl, pH 7.8.
2) Screen for Selecting Soluble Mutants
[0110] Three DTR sequence libraries produced by synthesis and
cloned into the pET28a(+) plasmid were transfected into the E. coli
strain BL21(DE3) (Geneart). For each library, clones were
subcultured in 2 or 4 96-well plates in culture medium in the
presence of a selection antibiotic and of expression inducer
(IPTG). After growth, the bacteria were lyzed using a Bugbuster.TM.
solution (0.5.times. final concentration) (Novagen) with the
addition of Lysonase.TM. (Novagen). After centrifugation of the
plates for 20 min at 2700 g at 4.degree. C., the presence of
inclusion bodies was evaluated well-by-well through the size of the
pellet, and the soluble protein fraction was identified by analysis
of the lysis supernatants on a polyacrylamide gel under denaturing
conditions and with Coomassie blue staining.
3) Test for Activity of the DTR Proteins by Inhibition of
Diphtheria Toxin Toxicity
[0111] Vero cells (ATCC CCL-81.TM.) were seeded into 96-well
Cytostar-T.TM. scintillating plates (Perkin Elmer) at 50 000 cells
per well in DMEM medium (Dulbecco's modified Eagle's minimum
essential medium) supplemented with 2 mM of glutamine, 1% of a
penicillin/streptomycin solution, 1% of a solution of nonessential
amino acids and 10% of fetal calf serium. Variable concentrations
of diphtheria toxin (Sigma) were added in duplicates. These
conditions were repeated in the presence of the antagonist tested:
DTR.sub.WT, mutant DTR or CRM197 protein (Sigma). After incubation
for 22 h at 37.degree. C. in a 5% CO.sub.2 atmosphere, the culture
medium was replaced with leucine-free medium containing 1
.mu.Ci/well of .sup.14[C]-leucine (GE Health Care Life Sciences).
After incubation for 5 h at 37.degree. C. in a 5% CO.sub.2
atmosphere, the radioactivity incorporated into the cells was
counted by placing the plates, covered with an adhesive film, in a
MicroBeta.RTM. apparatus (Wallac).
4) Test for Activity of the DTR Proteins by Inhibition of the
Proliferating Activity of HB-EGF
[0112] The test uses a murine lymphoid cell line Ba/F3 (Palacios, R
& Steinmetz, M., Cell, 1985, 81, 727-734) transfected in the
laboratory with the EGFR gene. This line is dependent on HB-EGF or
on amphiregulin for its growth. The cells were seeded into 96-well
Nunclon.TM. plates (Nunc) at 10 000 cells per well in RPMI (Roswell
Park Memorial Institute) 1640 medium supplemented with 2 mM of
glutamine, 1% of a penicillin/streptomycin solution, 1% of a
solution of nonessential amino acids and 10% of fetal calf serum.
Variable concentrations of HB-EGF or of amphiregulin were added in
duplicate. These conditions were repeated in the presence of the
antagonist tested: mutant DTR or CRM197 protein. After incubation
for 24 h at 37.degree. C. in a 5% CO.sub.2 atmosphere, 1
.mu.Ci/well of .sup.3[H]-thymidine (GE Health Care Life Sciences)
was added to each well. After incubation for 5 h at 37.degree. C.
in a 5% CO.sub.2 atmosphere, the cells were aspirated on glass
fiber filter (filtermat A, Wallac) using a Tomtec.RTM. apparatus.
After drying of the filters, the latter were placed in a sealed bag
in the presence of scintillation fluid and the radioactivity
incorporated into the cells was counted in a MicroBeta.RTM.
apparatus (Wallac).
5) Identification of CD4 T Epitopes of the DTR Protein
[0113] The identification of the CD4 T epitopes of the DTR protein
is carried out by analysis of the DTR peptides recognized by
DTR-specific CD4 T lymphocyte lines, restricted with respect to the
HLA-DRB1 molecules which are predominant in caucasian phenotypes.
The protocols used are those previously described in application WO
2010/076413 with the exception of the following modifications: (1)
the DTR-specific CD4 T lympocyte lines are produced by coculturing
of donor CD4 T lymphocytes with autologous mature dendritic cells
loaded with a pool of overlapping DTR peptides, and (2) the
specificity of the lines produced is analyzed by means of an
ELISPOT-IFN-.gamma. assay using autologous peripheral blood
mononuclear cells (PBMCs) loaded either with the peptide pool used
to produce the CD4 T lymphocyte line, in order to verify the
specificity of the line for DTR, or with a peptide of the pool, in
order to determine the specificity of each line.
a) Isolation of the CD4 T Lymphocytes from PBMCs
[0114] Seven donors of different age and different HLA-DRB1
phenotype were selected such that all of these donors express the 8
HLA-DRB1 molecules which are predominant in caucasian phenotypes
(HLA-DR1; HLA-DR3; HLA-DR4; HLA-DR7; HLA-DR11; HLA-DR13; HLA-DR15;
HLA-DR8). The CD4 T lymphocytes of each donor were isolated from
the peripheral blood mononuclear cells (PBMCs), with a degree of
purity greater than 98%, by magnetic sorting on a column using
magnetic beads coupled to an anti-CD4 antibody, according to a
standard procedure defined by the manufacturer (Myltenyi
Biotech).
b) Production and Characterization of the DTR-Specific CD4 T
Lymphocyte Lines
[0115] 25 overlapping peptides of 15 amino acids covering the
entire DTR sequence was synthesized (Intavis Bioanalytical
Instruments).
TABLE-US-00002 TABLE II Overlapping peptides covering the DTR
sequence (SEQ ID NOs: 18 to 42) Peptide Locali- Amino acid sequence
zation 1 378-392 M G Y S P G H K T Q P F L H D 2 385-399 K T Q P F
L H D G Y A V S W N 3 391-405 H D G Y A V S W N T V E D S I 4
397-411 S W N T V E D S I I R T G F Q 5 403-417 D S I I R T G F Q G
E S G H D 6 409-423 G F Q G E S G H D I K I T A E 7 415-429 G H D I
K I T A E N T P L P I 8 421-435 T A E N T P L P I A G V L L P 9
427-441 L P I A G V L L P T I P G K L 10 433-447 L L P T I P G K L
D V N K S K 11 439-453 G K L D V N K S K T H I S V N 12 445-459 K S
K T H I S V N G R K I R M 13 451-465 S V N G R K I R M R C R A I D
14 457-471 I R M R C R A I D G D V T F C 15 463-477 A I D G D V T F
C R P K S P V 16 469-483 T F C R P K S P V Y V G N G V 17 475-489 S
P V Y V G N G V H A N L H V 18 482-496 G V H A N L H V A F H R S S
S 19 488-502 H V A F H R S S S E K I H S N 20 494-508 S S S E K I H
S N E I S S D S 21 500-514 H S N E I S S D S I G V L G Y 22 506-520
S D S I G V L G Y Q K T V D H 23 512-526 L G Y Q K T V D H T K V N
S K 24 518-532 V D H T K V N S K L S L F F E 25 521-535 T K V N S K
L S L F F E I K S
[0116] The peptides were grouped together in 3 pools:
[0117] Pool 1: peptides 1 to 8
[0118] Pool 2: peptides 9 to 16
[0119] Pool 3: peptides 17 to 25.
[0120] Each of the pools is used in vitro to repeatedly
independently sensitize CD4 T lymphocytes from the donors selected
for the study. A minimum of 30 coculture wells are produced per
pool of peptides. Firstly, the sensitized CD4 T cells capable of
recognizing the peptide pool used during the stimulation, called
CD4 T lymphocyte lines, are selected by means of an
ELISPOT-IFN-.gamma. assay using autologous PBMCs loaded with the
peptide pool, as antigen-presenting cells. Secondly, the peptide(s)
specifically recognized by the CD4 T lines selected during the
first analysis are identified by means of an ELISPOT-IFN-.gamma.
assay using autologous PBMCs separately loaded with each of the
peptides of the pool, as antigen-presenting cells. The antigen
(isolated peptide or peptide pool) recognition specificity is
defined by: (1) a ratio between the number of CD4 T lymphocytes
producing IFN-.gamma. in response to the antigen (PBMCs+peptides)
compared with the background noise (absence of the antigen, i.e.
PBMCs alone) which is greater than 2, and (2) a minimum number of
30 spots in the presence of antigen once the background noise has
been subtracted.
6) Evaluation of the Antigenicity of the DTR Proteins
[0121] At each step, the incubations were carried out under one or
other of the following three conditions: 1 h at 37.degree. C. or 2
h at 20.degree. C. or 16 h at 4.degree. C. The proteins tested
(CRM197, catalytic domain, translocation domain, DTR1 and DTR8)
were solubilized at the concentration of 1.7.times.10.sup.-8 M in
the PBS buffer at pH 7.4 so as to be adsorbed onto 96-well
Maxisorp.TM. plates (Nunc). The wells were saturated with a
solution of bovine serum albumin (BSA) (Sigma) at 3% in PBS. After
4 washes with a solution of PBS buffer containing 0.05% of Tween
20, the healthy donor sera were incubated in duplicate in the wells
after dilution to 1/20.sup.th, 1/200.sup.th or 1/2000.sup.th in a
PBS buffer containing 0.2% of BSA and 0.05% of Tween 20. After 4
washes with a solution of PBS buffer containing 0.05% de Tween 20,
a goat anti-human IgG antibody conjugated to alkaline phosphatase
(Sigma) was incubated in the wells after dilution to 1/200.sup.th
in a solution of PBS containing 0.2% of BSA and 0.05% of Tween 20.
After 4 washes in a solution of PBS containing 0.05% of Tween 20,
the test was visualized by incubation in a 0.1 mM solution of
4-methylumbelliferyl phosphate (Sigma) diluted in the buffer of 50
mM carbonate, 1 mM MgCl.sub.2 at pH 9.8 for 30 min at 20.degree. C.
The fluorescence of the wells (emission at 450 nm) was measured in
a Victor fluorimeter (Wallac) by excitation at 365 nm.
[0122] Before being tested, the sera were left to stand at
20.degree. C. for a day, and centrifuged at 10 000 g for 10 min,
and then 0.003% of thimerosal was added before storage at 4.degree.
C. or at -20.degree. C.
EXAMPLE 2
Improvement of the Solubility of the DTR Protein
[0123] The DTR.sub.WT protein expressed in E. coli accumulates in
insoluble inclusion bodies. The protein could be obtained,
solubilized and purified only in the presence of 0.5% of sarkosyl
or of sodium dodecyl sulfate, which are detergents that are
incompatible with therapeutic use at these concentrations. The use
of other solubilizing molecules was unsuccessful (Tween-80,
sucrose, arginine). The use of chaotropic agents such as urea or
guanidine chloride for solubilizing the protein, followed by
dialysis against various folding buffers, also does not make it
possible to obtain a soluble functional protein. The influence of
the DTR truncation site relative to the complete diphtheria toxin
sequence was also studied. The DTR forms beginning at residue A379,
Y380, S381, P382, G383, H384 or K385 were all insoluble in the
absence of detergent.
[0124] The strategy used to increase the solubility of the DTR
protein consisted in mutating the hydrophobic residues present at
the surface of the protein with polar or charged hydrophilic
residues. This is because the hydrophobic residues at the surface
of a protein are potentially responsible for low solubility and for
a tendency to aggregate. The mutations to be introduced were
identified on the basis of molecular modeling. The potential effect
of the mutations on the structure of the protein is indicated in
Table III.
TABLE-US-00003 TABLE III Expected effect of the selected mutations
Posi- Muta- tions tions Observation regarding structure and
interactions Y380 -- Flexible at the end of the N-ter loop, no
stable hydrogen bond Y380E Ionic bond with K385 Y380K Ionic bond
with E532 P382 -- In a type II turn P382T Q387 -- In N-ter loop, no
stable hydrogen bond Q387E Ionic bond with Y380K P388 -- In N-ter
loop, just before a beta strand P388T L390 -- In a beta strand
L390N Donor of hydrogen bond for the CO group of the backbone of
Y394 L390T Beta-branched residue favored A395 -- In a beta strand
A395T Beta-branched residue favored N399 -- In a loop, no stable
hydrogen bond N399D Ionic bond with K419 N424 -- In a loop, no
stable hydrogen bond N424D Ionic bond with N481K N424E Ionic bond
with N481K N424K Ionic bond with E423 or N481E or N481D P426 -- At
the end of a loop P426T L427 -- In a beta strand, Van der Waals
contacts with Y394 L427K Van der Waals contacts with Y394, donor of
hydrogen bond for T425, ionic bond with E423 L427R Van der Waals
contacts with Y394, donor of hydrogen bond for T425, ionic bond
with E423 P428 -- In a bulge P428T P476 -- In a bulge P476T Y478 --
In a beta strand, Van der Waals contacts with P426, P428, P476
Y478D Y478N N481 -- In a loop, no stable hydrogen bond N481D Ionic
bond with N424K N481E Ionic bond with N424K N481K Ionic bond with
N424E or N424D V483 -- In a loop V483T
[0125] Three DTR DNA sequence libraries were prepared by synthesis
(Table IV). Each library contained sequences mutated on 4 or 5
codons chosen according to the molecular modeling data. Each
library corresponded to codons mutated in the same region of the
coding sequence. The sequences contained partial degeneracies of
the codons to be mutated so as to limit the possible mutations to
potentially acceptable hydrophilic residues according to the
modeling data (1, 2 or 3 possible mutations per position). The
possibility of retaining the wild-type codon was maintained, in the
case where the position tested cannot tolerate a mutation (Table
IV), except for Y380, the N-terminal position of which, which is
relatively not very constrained, was considered to be tolerant.
TABLE-US-00004 TABLE IV Combinations of possible mutations expected
for each of the three libraries of mutant sequences generated to
increase the solubility of the R domain (R1, R2, R3) Mutated
Mutated Possible Library region positions residues diversity R1
Y380 K/E 72 P382 P/T Q387 Q/E/K P388 P/T L390 L/T/N R2 N424 N/K/D/E
48 P426 P/T L427 L/R/K P428 P/T R3 P476 P/T 48 Y478 Y/N/D N481
N/K/D/E V483 V/T *The diversity indicates the number of
combinations of mutations possible for each of the libraries.
[0126] After transfection of the DNA libraries, the bacterial
colonies obtained, each corresponding to a given mutation
combination, were analyzed for their possible capacity to produce a
soluble mutant form of the DTR protein. For this, 740 clones
derived from the three libraries, representing 85% of the expected
diversity (41 different clones for each library), were subcultured
in 96-well plates, cultured under protein expression induction
conditions, centrifuged, and then lyzed in a lysis solution. After
centrifugation, the solubility of the proteins expressed by each
clone was evaluated by observation for a possible inclusion body
pellet at the bottom of the well and by analysis of the supernatant
by polyacrylamide gel electrophoresis under denaturing conditions
and with Coomassie blue staining (FIG. 1).
[0127] The analysis of the colonies resulted in selecting the
clones where there was an absence of pellet (pellet corresponding
to the inclusion bodies) or a pellet of reduced size and also a
large amount of protein in the lysis supernatant. Only the R1
library made it possible to generate clones producing soluble DTR
(FIG. 1), there being five of said clones. These clones, called
1D3, 1D6, 2C8, 5G5 and 1H3, comprise the nucleotide sequences
encoding the proteins SEQ ID NOs: 2 to 6, respectively. All the
clones were soluble after purification according to the method
described in Example 1. The 1D6 clone, also called G1, which makes
it possible to obtain the largest amount of DTR in soluble form
after expression at 30.degree. C., carried the mutations:
Y380K/Q387E/L390T.
[0128] The modeling approach led to the proposing of two additional
mutations, not represented in the R1 library: A395T and N399D.
These two mutations were each introduced into the 1D6 clone (or G1
clone) in order to search for an increased solubilizing effect,
which was the case for the A395T mutation (FIG. 2).
[0129] In total, the most soluble DTR protein, called DTR1 (SEQ ID
NO: 7), carries the mutations: Y380K/Q387E/L390T/A395T.
[0130] This does not rule out the fact that other DTR mutations may
further improve its solubility and its production in E. coli.
[0131] The HB-EGF-binding activity of the DTR1 protein was
evaluated through its capacity to inhibit the poisoning of Vero
cells by diphtheria toxin, and therefore the binding of the toxin
to pro-HB-EGF. The results show that DTR1 inhibits the poisoning of
Vero cells by diphtheria toxin in a dose-dependent manner (FIG. 3).
The inhibitory effect of DTR1 was compared with that of CRM197, of
the 1D6 clone and of DTR.sub.WT solubilized in 0.5% of sarkosyl.
The Kd values estimated by Schild regression for the three
interactions give the following values:
TABLE-US-00005 TABLE V Affinity for HB-EGF Protein Kd (pM) DTR1 ~49
Clone 1D6 ~25 DTR.sub.WT (+0.5% sarkosyl) ~6500 CRM197 ~3100
[0132] Biacore experiments in which HB-EGF was immobilized on the
chip of the apparatus and DTR1 was injected into the mobile
fraction in order to measure the association and dissociation
constants made it possible to confirm the estimated Kd of CRM197
and to show a much higher Kd for DTR1. However, the slowness of the
dissociation does not allow an accurate measurement of the
dissociation constant of DTR1 in Biacore. In the rest of the study,
the affinity of the mutants was estimated by cytotoxicity and S
child regression.
EXAMPLE 3
Improvement of the Binding Site of the DTR Protein
[0133] The structure of diphtheria toxin in interaction with HB-EGF
(Louie et al., Mol. Cell., 1997, 1, 67-78) makes it possible to
analyze the interface between the two proteins. This structural
analysis, coupled with in silico molecular modeling experiments,
made it possible to select 10 mutations in the DTR binding site in
order to increase the affinity of the protein for HB-EGF. These
mutations were intended to increase the enthalpy of the interaction
by promoting the formation of hydrogen bonds, of salt bridges
and/or of Van der Waals contacts between the two proteins. The
potential effect of the selected mutations on the structure of the
protein is indicated in Table VI.
TABLE-US-00006 TABLE VI Observations of structural nature regarding
the residues selected for increasing the affinity of the DTR
protein and expected effect of the mutations Positions Mutations
Observations of structural nature and potential interactions F389
-- In a beta strand, at the edge of the region of interaction with
HB-EGF, para-position close to a water molecule of the structured
interface and HB-EGF H139 F389Y Donor or acceptor of hydrogen bond
for a water molecule of the structured interface or HB-EGF H139
H391 -- In a beta strand, at the edge of the region of interaction
with HB-EGF, donor of hydrogen bond for HB-EGF E141 H391K Ionic
bond with HB-EGF E141 G510 -- In a beta strand, at the center of
the region of interaction with HB-EGF, next to a cavity between DTR
and HB-EGF, opposite the CO group of the backbone of HB-EGF C132
G510A Most conservative change for filling the cavity and
increasing Van der Waals contacts G510M Flexible hydrophobic side
chain for filling the cavity and increasing Van der Waals contacts
G510Q Donor of hydrogen bond for the CO group of the backbone of
HB-EGF C132 and/or acceptor of hydrogen H bond for the NH group of
the backbone of HB-EGF C134. G510S Small polar side chain for
filling the cavity and increasing Van der Waals contacts T521 -- In
a type II turn-like structure, at the edge of the region of
interaction with HB-EGF T521R Donor of hydrogen bond for the CO
group of the backbone of HB-EGF K111 and/or the CO group of the
backbone of HB-EGF K113 Q515 -- In a beta strand, at the edge of
the region of interaction with HB-EGF, donor of hydrogen bond for
the CO group of the backbone of HB-EGF L127 Q515E In an ionic and
hydrogen bond network involving K522R, HB-EGF R128, the CO group of
the backbone of HB-EGF R128, the CO group of the backbone of HB-EGF
L127 K522 -- In a beta strand, at the edge of the region of
interaction with HB-EGF, T517 hydrogen bond donor K522R In an ionic
and hydrogen bond network involving Q515E, HB-EGF R128, the CO
group of the backbone of HB-EGF R128, the CO group of the backbone
of HB-EGF L127
[0134] The mutations were introduced into the DTR1 protein by
site-directed mutagenesis (Table VII).
TABLE-US-00007 TABLE VII Mutations for improving the HB-EGF-binding
affinity of DTR identified by molecular modeling and tested
experimentally F389Y G510Q H391K G510S F389Y/H391K T521R G510A
Q515E/K522R G510M F389Y/H391K/Q515E/K522R
[0135] The proteins were expressed in E. coli. They were tested for
their capacity to inhibit the binding of diphtheria toxin to
pro-HB-EGF according to the cytotoxicity test described in Example
1. FIG. 4A shows the capacity of each mutant to possibly inhibit
the toxicity of diphtheria toxin on Vero cells. The results show
that only the F389Y and G510A mutants significantly inhibit the
toxicity of diphtheria toxin. The introduction of these two
mutations into DTR1 leads to a cumulative effect (FIG. 4B).
[0136] The most active mutant, corresponding to the DTR1 protein
carrying the F389Y and G510A mutations, was called DTR3 (SEQ ID NO:
8). Its HB-EGF-binding affinity was evaluated by the capacity of
increasing doses of DTR3 to inhibit the toxic effect of increasing
doses of diphtheria toxin on Vero cells as described in Example 2.
The Kd estimated by Schild regression from the EC50 values of the
inhibition curves is given in Table VIII.
TABLE-US-00008 TABLE VIII Affinity for HB-EGF Protein Kd (pM) DTR3
~9.5
[0137] This value suggests that DTR3 has an affinity for HB-EGF
which is at least 300 times greater than CRM197 and 5 times greater
than DTR1.
EXAMPLE 4
Decrease in the Immunogenicity of the DTR Protein by Elimination of
the Main CD4 T Epitopes
[0138] The capacity of 25 overlapping peptides covering the entire
sequence of DTR.sub.WT to activate specific CD4 T lymphocytes was
tested by ELISPOT, in in vitro immunization experiments using CD4 T
lymphocytes and dendritic cells purified from the blood of 7
healthy donors, of different age and of different HLA-DRB 1
phenotype.
[0139] The results show that the immune response against the
DTR.sub.WT protein is directed predominantly against five epitope
regions covering 60% of the protein and against which at least 71%
of the donors responded, i.e. 5 donors out of 7 studied (Table
IX):
[0140] the L.sub.427-L.sub.441 region (peptide 9) against which
specific CD4 T lymphocytes were detected for all of the donors
studied with a high magnitude (51 lines among 230 lines screened,
i.e. 22%),
[0141] the
H.sub.391-Q.sub.411/S.sub.451-D.sub.465/S.sub.475-N.sub.502 regions
(peptides 3-4, 13 and 17-18-19 respectively) against which,
overall, specific CD4 T cells were detected for 86% of the donors
(i.e. 6 donors/7) with a slightly more moderate magnitude than for
the region described above (20 to 30 specific CD4 T lymphocyte
lines, i.e. 8.5 to 13%), and
[0142] the S.sub.506-H.sub.520 region (peptide 22) against which
specific CD4 T cells were detected for 71% of the donors with a
magnitude of 8%.
TABLE-US-00009 TABLE IX Results, by peptide and by donor, for the
CD4 T lymphocyte lines specific for the DTR protein Donors P668
P661 P659 P663 P664 P667 P658 *Total HLA-DRB1 number of DR3 DR1
DR13 DR4 DR1 DR8 DR3 CD4 T Responder DR13 DR11 DR7 DR11 DR4 DR15
DR7 lines frequency Peptides/Age 52 44 29 62 57 44 30 1 378-392 1 1
14 2 385-399 1 4 2 7 43 3 391-405 1 3 2 1 4 11 71 4 397-411 1 3 1 1
13 8 27 86 5 403-417 1 1 14 6 409-423 1 6 7 29 7 415-429 1 1 14 8
421-435 1 1 2 29 9 427-441 3 3 5 3 13 4 20 51 100 10 433-447 1 2 1
18 22 57 11 439-453 2 2 1 5 43 12 445-459 9 5 3 17 43 13 451-465 9
14 1 2 3 1 30 86 14 457-471 2 1 1 4 43 15 463-477 10 10 14 16
469-483 2 1 3 29 17 475-489 7 2 8 5 1 21 71 18-19 482-502 4 1 5 4 1
3 18 86 20 494-508 2 2 4 29 21 500-514 1 1 4 6 43 22 506-520 1 2 6
4 5 18 71 23 512-526 3 2 5 29 24 518-532 2 1 3 29 25 521-535 1 1 14
Total 27 16 44 23 28 30 40 % 30 13 49 19 31 33 44 Total number of
CD4 T lymphocyte lines specific for a peptide among the 230 lines
screened
[0143] Since 5 epitope regions were identified, it is possible to
envision the mutation of these epitopes in order to reduce their
binding to HLA-II molecules. The ProPred server
(http://www.imtech.res.in/raghava/propred/) was used to predict,
within these five regions of DTR.sub.WT, the sequences capable of
binding the 8 HLA class II alleles which are the most common in the
population (Table X). The same analysis applied to the mutated
sequences of DTR1 shows that the mutations introduced in order to
improve the solubility of DTR reduced the immunogenicity of the
protein (epitopes predicted for the region 378-403). Indeed, the
epitope predicted to bind DRB1.sub.--0301 disappears and one of the
epitopes predicted to bind DRB1.sub.--0401 experiences an increase
in its threshold, that is to say a decrease in its predicted
affinity for the HLA molecule.
TABLE-US-00010 TABLE X Prediction of the sequences capable of
binding the 8 HLA class II alleles which are the most common
(DRB1_0101, DRB1_0301, DRB1_0401, DRB1_0701, DRB1_1101, DRB1_1301,
DRB1_1501, DRB5_0101) within the 5 regions identified as
immunogenic by means of a CD4 T lymphocyte activation assay. The
peptide sequences correspond to the sequences SEQ ID NOs: 43 to
109. The second column of the table gives the region studied. The
first column indicates the mutations proposed for inhibiting the
binding of the predicted sequences to the HLA class II molecules.
The subsequent columns indicate, for each HLA allele considered,
the presence or absence of sequence capable of binding this HLA
molecule. Each sequence is preceded by a threshold value reflected
in the binding strength: 1/2 (strong binding), 3/4 (medium
binding), 5/6 (weak binding). The residues in bold correspond to
the mutations proposed for abolishing the binding of the sequences
to the HLA allele considered. Variant DRB1_0101 DRB1_0301 DRB1_0401
DRB1_0701 Sequence (378-403) WT MGYSPGHKTQPFLHDGYAVSWNTVED -- 6:
FLHDGYAVS 3: FLHDGYAVS -- 5: YAVSWNTVE DTR1
MGKSPGHKTEPFTHDGYTVSWNTVED -- -- 5: FTHDGYTVS -- 5: YTVSWNTVE
Sequence (391-411) DTR1 HDGYTVSWNTVEDSIIRTGFQ -- -- 4: VSWNTVEDS 6:
WNTVEDSII 5: YTVSWNTVE N399K HDGYTVSWKTVEDSIITGFQ -- -- -- 5:
WKTVEDSII V401Q HDGYTVSWNTQEDSIIRTGFQ -- -- 5: YTVSWNTQE -- N399K
HDGYTVSWKTQEDSIIRTGFQ -- -- -- -- V401Q Sequence (427-441) DTR1
LPIAGVLLPTIPGKL -- 6: VLLPTIPGK -- 3: LLPTIPGKL L427Q
QPIAGVLLPTIPGKL -- 6: VLLPTIPGK -- 3: LLPTIPGKL T436K
LPIAGVLLPKIPGKL -- 6: VLLPKIPGK -- -- L427Q QPIAGVLLPKIPGKL -- 6:
VLLPKIPGK -- -- T436K Sequence (451-465) DTR1 SVNGRKIRMRCRAID -- 3:
IRMRCRAID -- -- I457D SVNGRKDRMRCRAID -- -- -- -- I457E
SVNGRKERMRCRAID -- -- -- -- V452T STNGRKIRMRCRAID -- 3: IRMRCRAID
-- -- R460T SVNGRKIRMTCRAID -- 3: IRMTCRAID -- -- A463D
SVNGRKIRMRCRDID -- 5: IRMRCRDID -- -- V452T STNGRKIRMTCRDID -- 5:
IRMTCRDID -- -- R460T A463D Sequence (475-502) DTR1
SPVYVGNGVHANLHVAFHRSSSEKIHSN 3: YVGNGVHAN -- 1: YVGNGVHAN 1:
FHRSSSEKI 3: FHRSSSEKI 1: FHRSSSEKI 4: VYVGNGVHA Y478T
SPVTVGNGVHANLHVAFHRSSSEKIHSN 3: FHRSSSEKI -- 1: FHRSSSEKI 1:
FHRSSSEKI V483D SPVYVGNGDHANLHVAFHRSSSEKIHSN 3: FHRSSSEKI -- 1:
FHRSSSEKI 1: FHRSSSEKI 5: YVGNGDHAN V483E
SPVYVGNGEHANLHVAFHRSSSEKIHSN 3: FHRSSSEKI -- 1: FHRSSSEKI 1:
FHRSSSEKI V483H SPVYVGNGHHANLHVAFHRSSSEKIHSN 3: FHRSSSEKI -- 1:
FHRSSSEKI 1: FHRSSSEKI 5: VYVGNGHHA V483Q
SPVYVGNGQHANLHVAFHRSSSEKIHSN 3: FHRSSSEKI -- 1: FHRSSSEKI 1:
FHRSSSEKI 5: VYVGNGQHA 6: YVGNGQHAN A490G
APVYVGNGVHANLHVGFHRSSSEKIHSN 3: YVGNGVHAN -- 1: YVGNGVHAN 1:
FHRSSSEKI 3: FHRSSSEKI 1: FHRSSSEKI 4: VYVGNGVHA 6: VGFHRSSSE H492E
SPVYVGNGVHANLHVAFERSSSEKIHSN 3: YVGNGVHAN -- 1: YVGNGVHAN 1:
FERSSSEKI 4: VYVGNGVHA 2: FERSSSEKI 5: FERSSSEKI S494K
SPVYVGNGVHANLHVAFHRKSSEKIHSN 3: YVGNGVHAN -- 1: YVGNGVHAN 2:
FHRKSSEKI 4: YVYGNGVHA 5: FHRKSSEKI S496K
SPVYVGNGVHANLHVAFHRSSKEKIHSN 3: YVGNGVHAN 4: FHRSSKEKI 1: YVGNGVHAN
1: FHRSSKEKI 4: VYVGNGVHA Y478T SPVTVGNGVHANLHVGFERKSKEKIHSN -- --
-- -- A490G H492E S494K S496K Sequence (506-520) DTR1
SDSIGVLGYQKTVDH -- -- 1: LGYQKTVDH -- T517D SDSIGVLGYQKDVDH -- --
-- -- T517E SDSIGVLGYQKEVDH -- -- -- -- Variant DRB1_1101 DRB1_1301
DRB1_1501 DRB5_0101 Sequence (378-403) WT
MGYSPGHKTQPFLHDGYAVSWNTVED -- -- -- -- DTR1
MGKSPGHKTEPFTHDGYTVSWNTVED -- -- -- -- Sequence (391-411) DTR1
HDGYTVSWNTVEDSIIRTGFQ -- -- -- -- N399K HDGYTVSWKTVEDSIITGFQ -- 6:
VSWKTVEDS -- -- V401Q HDGYTVSWNTQEDSIIRTGFQ -- -- -- -- N399K
HDGYTVSWKTQEDSIIRTGFQ -- -- -- -- V401Q Sequence (427-441) DTR1
LPIAGVLLPTIPGKL 3: LPIAGVLLP 4: LPIAGVLLP -- 2: LLPTIPGKL L427Q
QPIAGVLLPTIPGKL -- -- -- 2: LLPTIPGKL T436K LPIAGVLLPKIPGKL 3:
LPIAGVLLP 4: LPIAGVLLP -- -- L427Q QPIAGVLLPKIPGKL -- -- -- --
T436K Sequence (451-465) DTR1 SVNGRKIRMRCRAID 3: IRMRCRAID 1:
VNGRKIRMR 4: IRMRCRAID -- 1: IRMRCRAID I457D SVNGRKDRMRCRAID -- --
-- -- I457E SVNGRKERMRCRAID -- -- -- -- V452T STNGRKIRMRCRAID 3:
IRMRCRAID 1: IRMRCRAID 4: IRMRCRAID -- R460T SVNGRKIRMTCRAID 3:
IRMTCRAID 3: VNGRKIRMT 6: IRMTCRAID 3: IRMTCRAID A463D
SVNGRKIRMRCRDID -- 1: VNGRKIRMR -- -- 3: IRMRCRDID V452T
STNGRKIRMTCRDID -- -- -- -- R460T A463D Sequence (475-502) DTR1
SPVYVGNGVHANLHVAFHRSSSEKIHSN 2: YVGNGVHAN 1: LHVAFHRSS -- -- 5:
LHVAFHRSS 4: YVGNGVHAN Y478T SPVTVGNGVHANLHVAFHRSSSEKIHSN 5:
LHVAFHRSS 1: LHVAFHRSS -- -- V483D SPVYVGNGDHANLHVAFHRSSSEKIHSN 5:
LHVAFHRSS 1: LHVAFHRSS -- -- V483E SPVYVGNGEHANLHVAFHRSSSEKIHSN 5:
LHVAFHRSS 1: LHVAFHRSS -- -- V483H SPVYVGNGHHANLHVAFHRSSSEKIHSN 5:
VYVGNGHHA 1: LHVAFHRSS 6: VYVGNGHHA -- 5: LHVAFHRSS V483Q
SPVYVGNGQHANLHVAFHRSSSEKIHSN 5: YVGNGQHAN 1: LHVAFHRSS -- -- 5:
LHVAFHRSS A490G APVYVGNGVHANLHVGFHRSSSEKIHSN 2: YVGNGVHAN 4:
YVGNGVHAN -- -- 5: LHVGFHRSS H492E SPVYVGNGVHANLHVAFERSSSEKIHSN 2:
YVGNGVHAN 4: YVGNGVHAN -- -- 5: LHVAFERSS S494K
SPVYVGNGVHANLHVAFHRKSSEKIHSN 2: YVGNGVHAN 1: LHVAFHRKS -- -- 5:
LHVAFHRKS 4: YVGNGVHAN 4: VAFHRKSSE S496K
SPVYVGNGVHANLHVAFHRSSKEKIHSN 2: YVGNGVHAN 1: LHVAFHRSS -- -- 5:
LHVAFHRSS 4: YVGNGVHAN 5: FHRSSKEKI Y478T
SPVTVGNGVHANLHVGFERKSKEKIHSN -- -- -- -- A490G H492E S494K S496K
Sequence (506-520) DTR1 SDSIGVLGYQKTVDH 6: LGYQKTVDH 5: LGYQKTVDH
-- -- T517D SDSIGVLGYQKDVDH -- -- -- -- T517E SDSIGVLGYQKEVDH -- --
-- --
[0144] The prediction of the anchoring residues of the sequences
predicted to bind the HLA class II molecules made it possible to
propose a series of mutations indicated in bold in Table X,
intended to eliminate potential T epitopes. The mutations were
chosen so as to avoid potential destabilization of the protein,
which was tested in silico by molecular modeling. Any mutation
affecting the HB-EGF-binding site was excluded. The potential
effect of the proposed mutations on the structure of the protein is
indicated in Table XI.
TABLE-US-00011 TABLE XI Observations of structural nature regarding
the residues selected for eliminating CD4 T epitopes of the DTR
protein and expected effect of the mutations Positions Mutations
Observations of structural nature and potential interactions N399
-- Exposed to the solvent, in a loop, no stable hydrogen bond N399K
Ionic bond with D417 and donor of hydrogen bond for the CO group of
the backbone of N486 V401 -- Exposed to the solvent, in a type I
turn V401Q Acceptor of hydrogen bond for K385 L427 -- Partially
buried, in a beta strand, Van der Waals contacts with Y394 L427Q
Donor of hydrogen bond for the CO group of the backbone of D392,
hydrocarbon-based side chain establishing Van der Waals contacts
with Y394 T436 -- Partially buried, in a loop, donor of hydrogen
bond for the CO group of the backbone of G466, Van der Waals
contacts with V443 T436H Acceptor of hydrogen bond for T469, Van
der Waals contacts with V443 T436K Ionic bond with A463D I457 --
Largely buried; in a beta strand; Van der Waals contacts with I450,
V452, P473, V477 I457D Acceptor of hydrogen bond for S475, the NH
group of the backbone of S475, the NH group of the backbone of K474
I457E Acceptor of hydrogen bond for S475, the NH group of the
backbone of S475, the NH group of the backbone of K474, or the NH
group of the backbone of V452 V452 -- Partially buried, in a beta
strand, Van der Waals contacts by a methyl group of the side chain
with I450, I457, V477 V452T Van der Waals contacts by the methyl
group of the side chain with I450, I457, V477 A463 -- Exposed to
the solvent, in a beta strand A463D Ionic bond with T436K R460 --
Exposed to the solvent, in a beta strand, is part of a basic patch
containing other arginines potentially interacting with heparan
sulfate groups bonded to the plasma membrane, close to HB-EGF,
donor of hydrogen bond for the CO group of the backbone of P473
R460T Beta-branched residue Y478 -- Exposed to the solvent, in a
beta strand, Van der Waals contacts with P426, P428, P476 Y478T
Beta-branched residue V483 -- Exposed to the solvent, in a loop
V483D V483E Acceptor of hydrogen bond for V452T, N453 V483H Donor
of hydrogen bond for the CO group of the backbone of Y478 V483Q
Acceptor or donor of hydrogen bond for V452T, donor of hydrogen
bond for the CO group of the backbone of Y478 A490 -- Partially
buried, in a beta strand A490G H492 -- Exposed to the solvent, in a
beta strand, acceptor or donor of hydrogen bond for S494 H492E
Ionic bond with S494K S494 -- Exposed to the solvent, in a loop,
acceptor of hydrogen bond for H492 S494K Ionic bond with H492E S496
-- Exposed to the solvent, in a loop S496K Donor of hydrogend bond
for Q411 T517 -- Exposed to the solvent, in a beta strand, acceptor
of hydrogen bond for K522 T517D Ionic bond with K522 T517E Ionic
bond with K522
[0145] The mutations indicated in Table XII were introduced
individually, or sometimes in combination, into the sequence of the
DTR3 protein, according to the modeling data, then gradually
accumulated when they altered neither the production of the
recombinant protein nor its biological activity. The biological
activity of the mutants was tested by inhibition of the toxicity of
diphtheria toxin on Vero cells.
TABLE-US-00012 TABLE XII Mutations introduced into DTR3 in order to
eliminate CD4 T epitopes N399K A463S H492E V401Q A463E S494K L427Q
A463D S496K L427N A463G H492E/S494K L427S T436K/A463D H492E/S496K
T436K V452T/R460T/A463D S494K/S496K T436H Y478T H492E/S494K/S496K
V452T V483D E497D I457D V483E T436H/E497D I457E V483H T517D R460T
V483Q T517E A463T A490G * In bold, the mutations which do not
significantly affect the expression and the activity of the
protein, which were therefore retained.
[0146] These experiments made it possible to successively retain
the following mutations: N399K, V452T, T517E, V483Q, H492E, S494K,
T436H and E497D.
[0147] The protein derived from DTR3 and accumulating the N399K,
V452T, T517E, V483Q, H492E and S494K mutations is called DTR8 (SEQ
ID NO: 9); it has an MW of 17458 Da. These mutations made it
possible to eliminate 10 of the 26 CD4 T epitopes identified in
DTR.sub.WT (Table XIII).
TABLE-US-00013 TABLE XIII Comparison of the number and of the
strength of the binding to HLA II of the CD4 T epitopes between
DTR.sub.WT and DTR8 Strength of Threshold value CD4 T epitopes
binding to reflecting the binding Total DTR HLA II strength 391-411
427-441 451-465 475-502 506-520 number DTR.sub.WT Strong 1 0 0 2 4
1 7 2 0 1 0 1 0 2 Medium 3 0 2 2 2 0 6 4 1 1 1 2 0 5 Weak 5 1 0 0 1
1 3 6 1 1 0 0 1 3 Total 3 5 5 10 3 26 DTR8 Strong 1 0 0 1 0 0 1 2 0
1 0 0 0 1 Medium 3 0 2 2 1 0 5 4 0 1 1 0 0 2 Weak 5 1 0 0 3 0 4 6 1
1 0 1 0 3 Total 2 5 4 5 0 16
[0148] Among these 10 epitopes are 7 of the 9 epitopes predicted as
being immunodominant epitopes of DTR.sub.WT. The capacity of the
resulting protein, DTR8, to induce a CD4-type immune response, i.e.
producing antibodies, is thus considerably reduced compared with
that of DTR.sub.WT in its wild-type form.
[0149] DTR8 contains six more mutations than DTR3. Since any
mutation or mutation combination is capable of impairing the
function of a protein, it is necessary to evaluate the effect of
these additional mutations on the DTR binding affinity for HB-EGF.
The HB-EGF-binding activity of the DTR8 protein was evaluated
through its capacity to inhibit the poisoning of Vero cells by
diphtheria toxin, and therefore the binding of the toxin to
pro-HB-EGF. The results (FIG. 5) show that DTR8 inhibits the
poisoning of Vero cells by diphtheria toxin in a dose-dependent
manner. The inhibitory effect of DTR8 was compared with that of
CRM197, DTR.sub.WT solubilized in 0.5% of sarkosyl, DTR3 and DTR1
(FIG. 3). The Kd values estimated by Schild regression for the four
interactions give the following values (Table XIV).
TABLE-US-00014 TABLE XIV Affinity of the proteins for HB-EGF
Protein Kd (pM) DTR8 2.2 DTR3 9.5 DTR1 49 DTR.sub.WT (+0.5%
sarkosyl) 6500 CRM197 3100
[0150] Notably and unexpectedly, the addition of the six mutations
intended to reduce the immunogenicity of DTR contributed to
increasing its affinity for HB-EGF. Overall, DTR8 has approximately
1400 times more affinity for HB-EGF than CRM197.
[0151] The HB-EGF-binding activity of the DTR8 protein was also
evaluated through its capacity to inhibit the binding of HB-EGF to
the EGFR in a Ba/F3 cell line transfected with the EGFR gene and
dependent on HB-EGF for its growth. The results (FIG. 6) show that
DTR8 inhibits the proliferation of the HB-EGF-dependent cells in a
dose-dependent manner. The inhibitory effect of DTR8 was compared
with that of CRM197 (FIG. 6). The results show that at least 300
times more CRM197 is necessary in order to obtain an equivalent
inhibitory effect. Consequently, DTR8 is at least 300 times more
effective than CRM197 in terms of binding to HB-EGF in
solution.
[0152] In conclusion, these results show that the DTR8 protein is
capable of binding to pro-HB-EGF molecules at the surface of cells
(FIG. 5) and to HB-EGF in solution (FIG. 6) and of blocking their
biological activity. The estimation of the Kd values for the
interactions suggests that DTR8 is 1400 times more powerful than
CRM197 in terms of binding to HB-EGF.
EXAMPLE 5
Evaluation of the Antigenicity of the DTR1 and DTR8 Proteins
[0153] The western population is vaccinated against diphtheria
toxin. Individuals who may benefit from treatment with a
therapeutic protein of DTR8 type could therefore have antibodies
capable of reacting against said protein. The capacity of the sera
of 20 healthy donors to recognize diphtheria toxin (in its mutated
form CRM197), and its various domains (catalytic (C), translocation
(T) and DTR (in the soluble mutated form DTR1)) was compared with
the DTR8 protein, by ELISA (FIG. 7). An antibody titer 20
corresponds to the background noise of the assay and therefore to
an absence of recognition. A titer threshold at 30 was arbitrarily
set in order to distinguish the sera exhibiting a weak or strong
response.
[0154] The results (FIG. 7) show that 16/20 donors have antibodies
against diphtheria toxin. 14/20 donors exhibit a medium to strong
antibody response. However, the majority of the antibodies present
in each serum considered individually are directed against the C
domain of the toxin (FIG. 7). Indeed, 12 sera exhibit a response
above the threshold (medium to strong response) and 4 sera exhibit
a response below the threshold (weak response). If the reactivity
of the sera against the soluble form of the R domain (DTR1) is
considered, 15/20 sera recognize the R domain. However, only 7 sera
exhibit a response above the threshold (medium to strong response).
Notably, the DTR8 protein is considerably less well recognized by
the sera of the donors than DTR1. Indeed, only 3/20 sera exhibit
medium to strong reactivity against DTR8 and 2 sera exhibit weak
reactivity (FIG. 7).
[0155] In conclusion, these results show that the antigenicity of
the DTR8 protein is weak and considerably reduced compared with
that of CRM197. This antigenicity is also reduced in comparison
with that of the DTR1 protein, corresponding to the soluble form of
DTR carrying the lowest number of mutations. In other words, the
mutations introduced into DTR in order to increase its affinity for
HB-EGF and to reduce its immunogenicity contribute to considerably
reducing its antigenicity.
Sequence CWU 1
1
1091535PRTCorynebacterium diphtheriae 1Gly Ala Asp Asp Val Val Asp
Ser Ser Lys Ser Phe Val Met Glu Asn 1 5 10 15 Phe Ser Ser Tyr His
Gly Thr Lys Pro Gly Tyr Val Asp Ser Ile Gln 20 25 30 Lys Gly Ile
Gln Lys Pro Lys Ser Gly Thr Gln Gly Asn Tyr Asp Asp 35 40 45 Asp
Trp Lys Gly Phe Tyr Ser Thr Asp Asn Lys Tyr Asp Ala Ala Gly 50 55
60 Tyr Ser Val Asp Asn Glu Asn Pro Leu Ser Gly Lys Ala Gly Gly Val
65 70 75 80 Val Lys Val Thr Tyr Pro Gly Leu Thr Lys Val Leu Ala Leu
Lys Val 85 90 95 Asp Asn Ala Glu Thr Ile Lys Lys Glu Leu Gly Leu
Ser Leu Thr Glu 100 105 110 Pro Leu Met Glu Gln Val Gly Thr Glu Glu
Phe Ile Lys Arg Phe Gly 115 120 125 Asp Gly Ala Ser Arg Val Val Leu
Ser Leu Pro Phe Ala Glu Gly Ser 130 135 140 Ser Ser Val Glu Tyr Ile
Asn Asn Trp Glu Gln Ala Lys Ala Leu Ser 145 150 155 160 Val Glu Leu
Glu Ile Asn Phe Glu Thr Arg Gly Lys Arg Gly Gln Asp 165 170 175 Ala
Met Tyr Glu Tyr Met Ala Gln Ala Cys Ala Gly Asn Arg Val Arg 180 185
190 Arg Ser Val Gly Ser Ser Leu Ser Cys Ile Asn Leu Asp Trp Asp Val
195 200 205 Ile Arg Asp Lys Thr Lys Thr Lys Ile Glu Ser Leu Lys Glu
His Gly 210 215 220 Pro Ile Lys Asn Lys Met Ser Glu Ser Pro Asn Lys
Thr Val Ser Glu 225 230 235 240 Glu Lys Ala Lys Gln Tyr Leu Glu Glu
Phe His Gln Thr Ala Leu Glu 245 250 255 His Pro Glu Leu Ser Glu Leu
Lys Thr Val Thr Gly Thr Asn Pro Val 260 265 270 Phe Ala Gly Ala Asn
Tyr Ala Ala Trp Ala Val Asn Val Ala Gln Val 275 280 285 Ile Asp Ser
Glu Thr Ala Asp Asn Leu Glu Lys Thr Thr Ala Ala Leu 290 295 300 Ser
Ile Leu Pro Gly Ile Gly Ser Val Met Gly Ile Ala Asp Gly Ala 305 310
315 320 Val His His Asn Thr Glu Glu Ile Val Ala Gln Ser Ile Ala Leu
Ser 325 330 335 Ser Leu Met Val Ala Gln Ala Ile Pro Leu Val Gly Glu
Leu Val Asp 340 345 350 Ile Gly Phe Ala Ala Tyr Asn Phe Val Glu Ser
Ile Ile Asn Leu Phe 355 360 365 Gln Val Val His Asn Ser Tyr Asn Arg
Pro Ala Tyr Ser Pro Gly His 370 375 380 Lys Thr Gln Pro Phe Leu His
Asp Gly Tyr Ala Val Ser Trp Asn Thr 385 390 395 400 Val Glu Asp Ser
Ile Ile Arg Thr Gly Phe Gln Gly Glu Ser Gly His 405 410 415 Asp Ile
Lys Ile Thr Ala Glu Asn Thr Pro Leu Pro Ile Ala Gly Val 420 425 430
Leu Leu Pro Thr Ile Pro Gly Lys Leu Asp Val Asn Lys Ser Lys Thr 435
440 445 His Ile Ser Val Asn Gly Arg Lys Ile Arg Met Arg Cys Arg Ala
Ile 450 455 460 Asp Gly Asp Val Thr Phe Cys Arg Pro Lys Ser Pro Val
Tyr Val Gly 465 470 475 480 Asn Gly Val His Ala Asn Leu His Val Ala
Phe His Arg Ser Ser Ser 485 490 495 Glu Lys Ile His Ser Asn Glu Ile
Ser Ser Asp Ser Ile Gly Val Leu 500 505 510 Gly Tyr Gln Lys Thr Val
Asp His Thr Lys Val Asn Ser Lys Leu Ser 515 520 525 Leu Phe Phe Glu
Ile Lys Ser 530 535 2158PRTartificial sequencesynthetic protein
(DTR variant Y380K/L390T encoded by clone 1D3) 2Met Gly Lys Ser Pro
Gly His Lys Thr Gln Pro Phe Thr His Asp Gly 1 5 10 15 Tyr Ala Val
Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe
Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40
45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu
50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn Gly Arg
Lys Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr
Phe Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly Val
His Ala Asn Leu His Val 100 105 110 Ala Phe His Arg Ser Ser Ser Glu
Lys Ile His Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Gly Val
Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 Lys Val Asn Ser
Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155
3158PRTartificial sequencesynthetic protein (DTR variant
Y380K/Q387E/ L390T encoded by clone 1D6) 3Met Gly Lys Ser Pro Gly
His Lys Thr Glu Pro Phe Thr His Asp Gly 1 5 10 15 Tyr Ala Val Ser
Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe Gln
Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40 45
Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu 50
55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn Gly Arg Lys
Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe
Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly Val His
Ala Asn Leu His Val 100 105 110 Ala Phe His Arg Ser Ser Ser Glu Lys
Ile His Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Gly Val Leu
Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 Lys Val Asn Ser Lys
Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155 4158PRTartificial
sequencesynthetic protein (DTR variant Y380K/Q387E/ P388T/L390T
encoded by clone 2C8) 4Met Gly Lys Ser Pro Gly His Lys Thr Glu Thr
Phe Thr His Asp Gly 1 5 10 15 Tyr Ala Val Ser Trp Asn Thr Val Glu
Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe Gln Gly Glu Ser Gly His
Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40 45 Pro Leu Pro Ile Ala
Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu 50 55 60 Asp Val Asn
Lys Ser Lys Thr His Ile Ser Val Asn Gly Arg Lys Ile 65 70 75 80 Arg
Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe Cys Arg Pro 85 90
95 Lys Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val
100 105 110 Ala Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn Glu
Ile Ser 115 120 125 Ser Asp Ser Ile Gly Val Leu Gly Tyr Gln Lys Thr
Val Asp His Thr 130 135 140 Lys Val Asn Ser Lys Leu Ser Leu Phe Phe
Glu Ile Lys Ser 145 150 155 5158PRTartificial sequencesynthetic
protein (DTR variant Y380K/P382T/ Q387E/L390T encoded by clone 2G5)
5Met Gly Lys Ser Thr Gly His Lys Thr Glu Pro Phe Thr His Asp Gly 1
5 10 15 Tyr Ala Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr
Gly 20 25 30 Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala
Glu Asn Thr 35 40 45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr
Ile Pro Gly Lys Leu 50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile
Ser Val Asn Gly Arg Lys Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile
Asp Gly Asp Val Thr Phe Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr
Val Gly Asn Gly Val His Ala Asn Leu His Val 100 105 110 Ala Phe His
Arg Ser Ser Ser Glu Lys Ile His Ser Asn Glu Ile Ser 115 120 125 Ser
Asp Ser Ile Gly Val Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135
140 Lys Val Asn Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150
155 6158PRTartificial sequencesynthetic protein (DTR variant
Y380E/P382T/ Q387K/L390T encoded by clone 1H3) 6Met Gly Glu Ser Thr
Gly His Lys Thr Lys Pro Phe Thr His Asp Gly 1 5 10 15 Tyr Ala Val
Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe
Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40
45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu
50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn Gly Arg
Lys Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr
Phe Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly Val
His Ala Asn Leu His Val 100 105 110 Ala Phe His Arg Ser Ser Ser Glu
Lys Ile His Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Gly Val
Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 Lys Val Asn Ser
Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155
7158PRTartificial sequencesynthetic protein (DTR variant
Y380K/Q387E/ L390T/A395T named as DTR1) 7Met Gly Lys Ser Pro Gly
His Lys Thr Glu Pro Phe Thr His Asp Gly 1 5 10 15 Tyr Thr Val Ser
Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe Gln
Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40 45
Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu 50
55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn Gly Arg Lys
Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe
Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly Val His
Ala Asn Leu His Val 100 105 110 Ala Phe His Arg Ser Ser Ser Glu Lys
Ile His Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Gly Val Leu
Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 Lys Val Asn Ser Lys
Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155 8158PRTartificial
sequencesynthetic protein (DTR variant
Y380K/Q387E/F389Y/L390T/A395T/G510A named as DTR3) 8Met Gly Lys Ser
Pro Gly His Lys Thr Glu Pro Tyr Thr His Asp Gly 1 5 10 15 Tyr Thr
Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30
Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35
40 45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys
Leu 50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn Gly
Arg Lys Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val
Thr Phe Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly
Val His Ala Asn Leu His Val 100 105 110 Ala Phe His Arg Ser Ser Ser
Glu Lys Ile His Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Ala
Val Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 Lys Val Asn
Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155
9158PRTartificial sequencesynthetic protein (DTRvariant
Y380K/Q387E/F389Y/L390T/A395T/N399K/V452T/V483Q/H492E/S494K/G510A
/T517E named as DTR8) 9Met Gly Lys Ser Pro Gly His Lys Thr Glu Pro
Tyr Thr His Asp Gly 1 5 10 15 Tyr Thr Val Ser Trp Lys Thr Val Glu
Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe Gln Gly Glu Ser Gly His
Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40 45 Pro Leu Pro Ile Ala
Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu 50 55 60 Asp Val Asn
Lys Ser Lys Thr His Ile Ser Thr Asn Gly Arg Lys Ile 65 70 75 80 Arg
Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe Cys Arg Pro 85 90
95 Lys Ser Pro Val Tyr Val Gly Asn Gly Gln His Ala Asn Leu His Val
100 105 110 Ala Phe Glu Arg Lys Ser Ser Glu Lys Ile His Ser Asn Glu
Ile Ser 115 120 125 Ser Asp Ser Ile Ala Val Leu Gly Tyr Gln Lys Glu
Val Asp His Thr 130 135 140 Lys Val Asn Ser Lys Leu Ser Leu Phe Phe
Glu Ile Lys Ser 145 150 155 10477DNAartificial sequencesynthetic
polynucleotide (optimized coding sequence for DTR1) 10atg ggc aaa
agc ccg ggt cat aaa acc gag ccg ttt acc cat gat ggc 48Met Gly Lys
Ser Pro Gly His Lys Thr Glu Pro Phe Thr His Asp Gly 1 5 10 15 tat
acc gtg agc tgg aac acc gtg gaa gat agc att att cgt acc ggc 96Tyr
Thr Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25
30 ttt cag ggc gaa agc ggc cat gat att aaa att acc gcg gaa aac acc
144Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr
35 40 45 ccg ctg ccg att gcg ggt gtt ctg ctg ccg acc att ccg ggc
aaa ctg 192Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly
Lys Leu 50 55 60 gat gtg aac aaa agc aaa acc cat att agc gtg aac
ggc cgt aaa att 240Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn
Gly Arg Lys Ile 65 70 75 80 cgt atg cgt tgc cgt gcg att gat ggt gat
gtg acc ttt tgc cgt ccg 288Arg Met Arg Cys Arg Ala Ile Asp Gly Asp
Val Thr Phe Cys Arg Pro 85 90 95 aaa agc ccg gtg tat gtg ggc aac
ggc gtg cat gcg aac ctg cat gtg 336Lys Ser Pro Val Tyr Val Gly Asn
Gly Val His Ala Asn Leu His Val 100 105 110 gcg ttt cat cgt agc agc
agc gaa aaa atc cat agc aac gaa att agc 384Ala Phe His Arg Ser Ser
Ser Glu Lys Ile His Ser Asn Glu Ile Ser 115 120 125 agc gat agc att
ggc gtg ctg ggc tat cag aaa acc gtg gat cat acc 432Ser Asp Ser Ile
Gly Val Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 aaa gtg
aac tct aaa ctg agc ctg ttc ttc gaa atc aaa agc tga 477Lys Val Asn
Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155
11158PRTartificial sequenceSynthetic Construct 11Met Gly Lys Ser
Pro Gly His Lys Thr Glu Pro Phe Thr His Asp Gly 1 5 10 15 Tyr Thr
Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30
Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35
40 45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys
Leu 50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn Gly
Arg Lys Ile 65 70
75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe Cys Arg
Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn
Leu His Val 100 105 110 Ala Phe His Arg Ser Ser Ser Glu Lys Ile His
Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Gly Val Leu Gly Tyr
Gln Lys Thr Val Asp His Thr 130 135 140 Lys Val Asn Ser Lys Leu Ser
Leu Phe Phe Glu Ile Lys Ser 145 150 155 12477DNAartificial
sequencesynthetic polynucleotide (optimized coding sequence for
DTR3) 12atg ggc aaa agc ccg ggt cat aaa acc gag ccg tat acc cat gat
ggc 48Met Gly Lys Ser Pro Gly His Lys Thr Glu Pro Tyr Thr His Asp
Gly 1 5 10 15 tat acc gtg agc tgg aac acc gtg gaa gat agc att att
cgt acc ggc 96Tyr Thr Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile
Arg Thr Gly 20 25 30 ttt cag ggc gaa agc ggc cat gat att aaa att
acc gcg gaa aac acc 144Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile
Thr Ala Glu Asn Thr 35 40 45 ccg ctg ccg att gcg ggt gtt ctg ctg
ccg acc att ccg ggc aaa ctg 192Pro Leu Pro Ile Ala Gly Val Leu Leu
Pro Thr Ile Pro Gly Lys Leu 50 55 60 gat gtg aac aaa agc aaa acc
cat att agc gtg aac ggc cgt aaa att 240Asp Val Asn Lys Ser Lys Thr
His Ile Ser Val Asn Gly Arg Lys Ile 65 70 75 80 cgt atg cgt tgc cgt
gcg att gat ggt gat gtg acc ttt tgc cgt ccg 288Arg Met Arg Cys Arg
Ala Ile Asp Gly Asp Val Thr Phe Cys Arg Pro 85 90 95 aaa agc ccg
gtg tat gtg ggc aac ggc gtg cat gcg aac ctg cat gtg 336Lys Ser Pro
Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val 100 105 110 gcg
ttt cat cgt agc agc agc gaa aaa atc cat agc aac gaa att agc 384Ala
Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn Glu Ile Ser 115 120
125 agc gat agc att gcg gtg ctg ggc tat cag aaa acc gtg gat cat acc
432Ser Asp Ser Ile Ala Val Leu Gly Tyr Gln Lys Thr Val Asp His Thr
130 135 140 aaa gtg aac tct aaa ctg agc ctg ttc ttc gaa atc aaa agc
tga 477Lys Val Asn Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145
150 155 13158PRTartificial sequenceSynthetic Construct 13Met Gly
Lys Ser Pro Gly His Lys Thr Glu Pro Tyr Thr His Asp Gly 1 5 10 15
Tyr Thr Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr Gly 20
25 30 Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu Asn
Thr 35 40 45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro
Gly Lys Leu 50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile Ser Val
Asn Gly Arg Lys Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly
Asp Val Thr Phe Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly
Asn Gly Val His Ala Asn Leu His Val 100 105 110 Ala Phe His Arg Ser
Ser Ser Glu Lys Ile His Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser
Ile Ala Val Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135 140 Lys
Val Asn Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150 155
14477DNAartificial sequencesynthetic polynucleotide (optimized
coding sequence for DTR8) 14atg ggc aaa agc ccg ggt cat aaa acc gag
ccg tat acc cat gat ggc 48Met Gly Lys Ser Pro Gly His Lys Thr Glu
Pro Tyr Thr His Asp Gly 1 5 10 15 tat acc gtg agc tgg aaa acc gtg
gaa gat agc att att cgt acc ggc 96Tyr Thr Val Ser Trp Lys Thr Val
Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30 ttt cag ggc gaa agc ggc
cat gat att aaa att acc gcg gaa aac acc 144Phe Gln Gly Glu Ser Gly
His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40 45 ccg ctg ccg att
gcg ggt gtt ctg ctg ccg acc att ccg ggc aaa ctg 192Pro Leu Pro Ile
Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu 50 55 60 gat gtg
aac aaa agc aaa acc cat att agc acg aac ggc cgt aaa att 240Asp Val
Asn Lys Ser Lys Thr His Ile Ser Thr Asn Gly Arg Lys Ile 65 70 75 80
cgt atg cgt tgc cgt gcg att gat ggt gat gtg acc ttt tgc cgt ccg
288Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe Cys Arg Pro
85 90 95 aaa agc ccg gtg tat gtg ggc aac ggc cag cat gcg aac ctg
cat gtg 336Lys Ser Pro Val Tyr Val Gly Asn Gly Gln His Ala Asn Leu
His Val 100 105 110 gcg ttt gaa cgt aaa agc agc gaa aaa atc cat agc
aac gaa att agc 384Ala Phe Glu Arg Lys Ser Ser Glu Lys Ile His Ser
Asn Glu Ile Ser 115 120 125 agc gat agc att gcg gtg ctg ggc tat cag
aaa gaa gtg gat cat acc 432Ser Asp Ser Ile Ala Val Leu Gly Tyr Gln
Lys Glu Val Asp His Thr 130 135 140 aaa gtg aac tct aaa ctg agc ctg
ttc ttc gaa atc aaa agc tga 477Lys Val Asn Ser Lys Leu Ser Leu Phe
Phe Glu Ile Lys Ser 145 150 155 15158PRTartificial
sequenceSynthetic Construct 15Met Gly Lys Ser Pro Gly His Lys Thr
Glu Pro Tyr Thr His Asp Gly 1 5 10 15 Tyr Thr Val Ser Trp Lys Thr
Val Glu Asp Ser Ile Ile Arg Thr Gly 20 25 30 Phe Gln Gly Glu Ser
Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr 35 40 45 Pro Leu Pro
Ile Ala Gly Val Leu Leu Pro Thr Ile Pro Gly Lys Leu 50 55 60 Asp
Val Asn Lys Ser Lys Thr His Ile Ser Thr Asn Gly Arg Lys Ile 65 70
75 80 Arg Met Arg Cys Arg Ala Ile Asp Gly Asp Val Thr Phe Cys Arg
Pro 85 90 95 Lys Ser Pro Val Tyr Val Gly Asn Gly Gln His Ala Asn
Leu His Val 100 105 110 Ala Phe Glu Arg Lys Ser Ser Glu Lys Ile His
Ser Asn Glu Ile Ser 115 120 125 Ser Asp Ser Ile Ala Val Leu Gly Tyr
Gln Lys Glu Val Asp His Thr 130 135 140 Lys Val Asn Ser Lys Leu Ser
Leu Phe Phe Glu Ile Lys Ser 145 150 155 16477DNAartificial
sequencesynthetic polynucleotide (optimized coding sequence for
DTRwt) 16atg ggc tac agc ccg ggt cat aaa acc cag ccg ttt ctg cat
gat ggc 48Met Gly Tyr Ser Pro Gly His Lys Thr Gln Pro Phe Leu His
Asp Gly 1 5 10 15 tat gcg gtg agc tgg aac acc gtg gaa gat agc att
att cgt acc ggc 96Tyr Ala Val Ser Trp Asn Thr Val Glu Asp Ser Ile
Ile Arg Thr Gly 20 25 30 ttt cag ggc gaa agc ggc cat gat att aaa
att acc gcg gaa aac acc 144Phe Gln Gly Glu Ser Gly His Asp Ile Lys
Ile Thr Ala Glu Asn Thr 35 40 45 ccg ctg ccg att gcg ggt gtt ctg
ctg ccg acc att ccg ggc aaa ctg 192Pro Leu Pro Ile Ala Gly Val Leu
Leu Pro Thr Ile Pro Gly Lys Leu 50 55 60 gat gtg aac aaa agc aaa
acc cat att agc gtg aac ggc cgt aaa att 240Asp Val Asn Lys Ser Lys
Thr His Ile Ser Val Asn Gly Arg Lys Ile 65 70 75 80 cgt atg cgt tgc
cgt gcg att gat ggt gat gtg acc ttt tgc cgt ccg 288Arg Met Arg Cys
Arg Ala Ile Asp Gly Asp Val Thr Phe Cys Arg Pro 85 90 95 aaa agc
ccg gtg tat gtg ggc aac ggc gtg cat gcg aac ctg cat gtg 336Lys Ser
Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val 100 105 110
gcg ttt cat cgt agc agc agc gaa aaa atc cat agc aac gaa att agc
384Ala Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn Glu Ile Ser
115 120 125 agc gat agc att ggc gtg ctg ggc tat cag aaa acc gtg gat
cat acc 432Ser Asp Ser Ile Gly Val Leu Gly Tyr Gln Lys Thr Val Asp
His Thr 130 135 140 aaa gtg aac tct aaa ctg agc ctg ttc ttc gaa atc
aaa agc tga 477Lys Val Asn Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys
Ser 145 150 155 17158PRTartificial sequenceSynthetic Construct
17Met Gly Tyr Ser Pro Gly His Lys Thr Gln Pro Phe Leu His Asp Gly 1
5 10 15 Tyr Ala Val Ser Trp Asn Thr Val Glu Asp Ser Ile Ile Arg Thr
Gly 20 25 30 Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala
Glu Asn Thr 35 40 45 Pro Leu Pro Ile Ala Gly Val Leu Leu Pro Thr
Ile Pro Gly Lys Leu 50 55 60 Asp Val Asn Lys Ser Lys Thr His Ile
Ser Val Asn Gly Arg Lys Ile 65 70 75 80 Arg Met Arg Cys Arg Ala Ile
Asp Gly Asp Val Thr Phe Cys Arg Pro 85 90 95 Lys Ser Pro Val Tyr
Val Gly Asn Gly Val His Ala Asn Leu His Val 100 105 110 Ala Phe His
Arg Ser Ser Ser Glu Lys Ile His Ser Asn Glu Ile Ser 115 120 125 Ser
Asp Ser Ile Gly Val Leu Gly Tyr Gln Lys Thr Val Asp His Thr 130 135
140 Lys Val Asn Ser Lys Leu Ser Leu Phe Phe Glu Ile Lys Ser 145 150
155 1815PRTartificial sequencesynthetic peptide (peptide 1 DTR
378-392) 18Met Gly Tyr Ser Pro Gly His Lys Thr Gln Pro Phe Leu His
Asp 1 5 10 15 1915PRTartificial sequencesynthetic peptide (peptide
2 DTR 385-399) 19Lys Thr Gln Pro Phe Leu His Asp Gly Tyr Ala Val
Ser Trp Asn 1 5 10 15 2015PRTartificial sequencesynthetic peptide
(peptide 3 DTR 391-405) 20His Asp Gly Tyr Ala Val Ser Trp Asn Thr
Val Glu Asp Ser Ile 1 5 10 15 2115PRTartificial sequencesynthetic
peptide (peptide 4 DTR 397-411) 21Ser Trp Asn Thr Val Glu Asp Ser
Ile Ile Arg Thr Gly Phe Gln 1 5 10 15 2215PRTartificial
sequencesynthetic peptide (peptide 5 DTR 403-417) 22Asp Ser Ile Ile
Arg Thr Gly Phe Gln Gly Glu Ser Gly His Asp 1 5 10 15
2315PRTartificial sequencesynthetic peptide (peptide 6 DTR 409-423)
23Gly Phe Gln Gly Glu Ser Gly His Asp Ile Lys Ile Thr Ala Glu 1 5
10 15 2415PRTartificial sequencesynthetic peptide (peptide 7 DTR
415-429) 24Gly His Asp Ile Lys Ile Thr Ala Glu Asn Thr Pro Leu Pro
Ile 1 5 10 15 2515PRTartificial sequencesynthetic peptide (peptide
8 DTR 421-435) 25Thr Ala Glu Asn Thr Pro Leu Pro Ile Ala Gly Val
Leu Leu Pro 1 5 10 15 2615PRTartificial sequencesynthetic peptide
(peptide 9 DTR 427-441) 26Leu Pro Ile Ala Gly Val Leu Leu Pro Thr
Ile Pro Gly Lys Leu 1 5 10 15 2715PRTartificial sequencesynthetic
peptide (peptide 10 DTR 433-447) 27Leu Leu Pro Thr Ile Pro Gly Lys
Leu Asp Val Asn Lys Ser Lys 1 5 10 15 2815PRTartificial
sequencesynthetic peptide (peptide 11 DTR 439-453) 28Gly Lys Leu
Asp Val Asn Lys Ser Lys Thr His Ile Ser Val Asn 1 5 10 15
2915PRTartificial sequencesynthetic peptide (peptide 12 DTR
445-459) 29Lys Ser Lys Thr His Ile Ser Val Asn Gly Arg Lys Ile Arg
Met 1 5 10 15 3015PRTartificial sequencesynthetic peptide (peptide
13 DTR 451-465) 30Ser Val Asn Gly Arg Lys Ile Arg Met Arg Cys Arg
Ala Ile Asp 1 5 10 15 3115PRTartificial sequencesynthetic peptide
(peptide 14 DTR 457-471) 31Ile Arg Met Arg Cys Arg Ala Ile Asp Gly
Asp Val Thr Phe Cys 1 5 10 15 3215PRTartificial sequencesynthetic
peptide (peptide 15 DTR 463-477) 32Ala Ile Asp Gly Asp Val Thr Phe
Cys Arg Pro Lys Ser Pro Val 1 5 10 15 3315PRTartificial
sequencesynthetic peptide (peptide 16 DTR 469-483) 33Thr Phe Cys
Arg Pro Lys Ser Pro Val Tyr Val Gly Asn Gly Val 1 5 10 15
3415PRTartificial sequencesynthetic peptide (peptide 17 DTR
475-489) 34Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His
Val 1 5 10 15 3515PRTartificial sequencesynthetic peptide (peptide
18 DTR 482-496) 35Gly Val His Ala Asn Leu His Val Ala Phe His Arg
Ser Ser Ser 1 5 10 15 3615PRTartificial sequencesynthetic peptide
(peptide 19 DTR 488-502) 36His Val Ala Phe His Arg Ser Ser Ser Glu
Lys Ile His Ser Asn 1 5 10 15 3715PRTartificial sequencesynthetic
peptide (peptide 20 DTR 494-508) 37Ser Ser Ser Glu Lys Ile His Ser
Asn Glu Ile Ser Ser Asp Ser 1 5 10 15 3815PRTartificial
sequencesynthetic peptide (peptide 21 DTR 500-514) 38His Ser Asn
Glu Ile Ser Ser Asp Ser Ile Gly Val Leu Gly Tyr 1 5 10 15
3915PRTartificial sequencesynthetic peptide (peptide 22 DTR
506-520) 39Ser Asp Ser Ile Gly Val Leu Gly Tyr Gln Lys Thr Val Asp
His 1 5 10 15 4015PRTartificial sequencesynthetic peptide (peptide
23 DTR 512-526) 40Leu Gly Tyr Gln Lys Thr Val Asp His Thr Lys Val
Asn Ser Lys 1 5 10 15 4115PRTartificial sequencesynthetic peptide
(peptide 24 DTR 518-532) 41Val Asp His Thr Lys Val Asn Ser Lys Leu
Ser Leu Phe Phe Glu 1 5 10 15 4215PRTartificial sequencesynthetic
peptide (peptide 25 DTR 521-535) 42Thr Lys Val Asn Ser Lys Leu Ser
Leu Phe Phe Glu Ile Lys Ser 1 5 10 15 4326PRTartificial
sequencesynthetic peptide (DTRwt 378-403) 43Met Gly Tyr Ser Pro Gly
His Lys Thr Gln Pro Phe Leu His Asp Gly 1 5 10 15 Tyr Ala Val Ser
Trp Asn Thr Val Glu Asp 20 25 4426PRTartificial sequencesynthetic
peptide (DTR1 378-403) 44Met Gly Lys Ser Pro Gly His Lys Thr Glu
Pro Phe Thr His Asp Gly 1 5 10 15 Tyr Thr Val Ser Trp Asn Thr Val
Glu Asp 20 25 459PRTartificial sequencesynthetic peptide (DTRwt
389-397) 45Phe Leu His Asp Gly Tyr Ala Val Ser 1 5 469PRTartificial
sequencesynthetic peptide (DTRwt 394-402) 46Tyr Ala Val Ser Trp Asn
Thr Val Glu 1 5 479PRTartificial sequencesynthetic peptide (DTR1
389-397) 47Phe Thr His Asp Gly Tyr Thr Val Ser 1 5 489PRTartificial
sequencesynthetic peptide (DTR1 394-402) 48Tyr Thr Val Ser Trp Asn
Thr Val Glu 1 5 4921PRTartificial sequencesynthetic peptide (DTR1
391-411) 49His Asp Gly Tyr Thr Val Ser Trp Asn Thr Val Glu Asp Ser
Ile Ile 1 5 10 15 Arg Thr Gly Phe Gln 20 5021PRTartificial
sequencesynthetic peptide (N399K variant 391-411) 50His Asp Gly Tyr
Thr Val Ser Trp Lys Thr Val Glu Asp Ser Ile Ile 1 5 10 15 Arg Thr
Gly Phe Gln 20 5121PRTartificial sequencesynthetic peptide (V401Q
variant 391-411) 51His Asp Gly Tyr Thr Val Ser Trp Asn Thr Gln Glu
Asp Ser Ile Ile 1 5 10 15 Arg Thr Gly Phe Gln 20 5221PRTartificial
sequencesynthetic peptide (N399K/V401Q variant 391-411) 52His Asp
Gly Tyr Thr Val Ser Trp Lys Thr Gln Glu Asp Ser Ile Ile 1 5 10 15
Arg Thr Gly Phe Gln 20
539PRTartificial sequencesynthetic peptide (DTR1 396-404) 53Val Ser
Trp Asn Thr Val Glu Asp Ser 1 5 549PRTartificial sequencesynthetic
peptide (DTR1 394-402) 54Tyr Thr Val Ser Trp Asn Thr Val Glu 1 5
559PRTartificial sequencesynthetic peptide (DTR1 398-406) 55Trp Asn
Thr Val Glu Asp Ser Ile Ile 1 5 569PRTartificial sequencesynthetic
peptide (N399K variant 398-406) 56Trp Lys Thr Val Glu Asp Ser Ile
Ile 1 5 579PRTartificial sequencesynthetic peptide (N399K variant
396-404) 57Val Ser Trp Lys Thr Val Glu Asp Ser 1 5 589PRTartificial
sequencesynthetic peptide (V401Q variant 394-402) 58Tyr Thr Val Ser
Trp Asn Thr Gln Glu 1 5 5915PRTartificial sequencesynthetic peptide
(DTR1 427-441) 59Leu Pro Ile Ala Gly Val Leu Leu Pro Thr Ile Pro
Gly Lys Leu 1 5 10 15 6015PRTartificial sequencesynthetic peptide
(L427Q variant 427-441) 60Gln Pro Ile Ala Gly Val Leu Leu Pro Thr
Ile Pro Gly Lys Leu 1 5 10 15 6115PRTartificial sequencesynthetic
peptide (T436K variant 427-441) 61Leu Pro Ile Ala Gly Val Leu Leu
Pro Lys Ile Pro Gly Lys Leu 1 5 10 15 6215PRTartificial
sequencesynthetic peptide (L427Q/T436K variant 427-441) 62Gln Pro
Ile Ala Gly Val Leu Leu Pro Lys Ile Pro Gly Lys Leu 1 5 10 15
639PRTartificial sequencesynthetic peptide (DTR1 432-440) 63Val Leu
Leu Pro Thr Ile Pro Gly Lys 1 5 649PRTartificial sequencesynthetic
peptide (T436K variant 432-440) 64Val Leu Leu Pro Lys Ile Pro Gly
Lys 1 5 659PRTartificial sequencesynthetic peptide (DTR1 433-441)
65Leu Leu Pro Thr Ile Pro Gly Lys Leu 1 5 669PRTartificial
sequencesynthetic peptide (DTR1 427-435) 66Leu Pro Ile Ala Gly Val
Leu Leu Pro 1 5 6715PRTartificial sequencesynthetic peptide (DTR1
451-465) 67Ser Val Asn Gly Arg Lys Ile Arg Met Arg Cys Arg Ala Ile
Asp 1 5 10 15 6815PRTartificial sequencesynthetic peptide (I457D
variant 451-465) 68Ser Val Asn Gly Arg Lys Asp Arg Met Arg Cys Arg
Ala Ile Asp 1 5 10 15 6915PRTartificial sequencesynthetic peptide
(I457E variant 451-465) 69Ser Val Asn Gly Arg Lys Glu Arg Met Arg
Cys Arg Ala Ile Asp 1 5 10 15 7015PRTartificial sequencesynthetic
peptide (V452T variant 451-465) 70Ser Thr Asn Gly Arg Lys Ile Arg
Met Arg Cys Arg Ala Ile Asp 1 5 10 15 7115PRTartificial
sequencesynthetic peptide (R460T variant 451-465) 71Ser Val Asn Gly
Arg Lys Ile Arg Met Thr Cys Arg Ala Ile Asp 1 5 10 15
7215PRTartificial sequencesynthetic peptide (A463D variant 451-465)
72Ser Val Asn Gly Arg Lys Ile Arg Met Arg Cys Arg Asp Ile Asp 1 5
10 15 7315PRTartificial sequencesynthetic peptide
(V452T/R460T/A463D variant 451-465) 73Ser Thr Asn Gly Arg Lys Ile
Arg Met Thr Cys Arg Asp Ile Asp 1 5 10 15 749PRTartificial
sequencesynthetic peptide (DTR1 457-465) 74Ile Arg Met Arg Cys Arg
Ala Ile Asp 1 5 759PRTartificial sequencesynthetic peptide (R460T
variant 457-465) 75Ile Arg Met Thr Cys Arg Ala Ile Asp 1 5
769PRTartificial sequencesynthetic peptide (A463D variant 457-465)
76Ile Arg Met Arg Cys Arg Asp Ile Asp 1 5 779PRTartificial
sequencesynthetic peptide (V452T/R460T/A463D variant 451-465) 77Ile
Arg Met Thr Cys Arg Asp Ile Asp 1 5 789PRTartificial
sequencesynthetic peptide (DTR1 452-460) 78Val Asn Gly Arg Lys Ile
Arg Met Arg 1 5 799PRTartificial sequencesynthetic peptide (R460T
variant 452-460) 79Val Asn Gly Arg Lys Ile Arg Met Thr 1 5
8028PRTartificial sequencesynthetic peptide (DTR1 475-502) 80Ser
Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val Ala 1 5 10
15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8128PRTartificial sequencesynthetic peptide (Y478T variant 475-502)
81Ser Pro Val Thr Val Gly Asn Gly Val His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8228PRTartificial sequencesynthetic peptide (V483D variant 475-502)
82Ser Pro Val Tyr Val Gly Asn Gly Asp His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8328PRTartificial sequencesynthetic peptide (V483E variant 475-502)
83Ser Pro Val Tyr Val Gly Asn Gly Glu His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8428PRTartificial sequencesynthetic peptide (V483H variant 475-502)
84Ser Pro Val Tyr Val Gly Asn Gly His His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8528PRTartificial sequencesynthetic peptide (V483Q variant 475-502)
85Ser Pro Val Tyr Val Gly Asn Gly Gln His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8628PRTartificial sequencesynthetic peptide (A490G variant 475-502)
86Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val Gly 1
5 10 15 Phe His Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8728PRTartificial sequencesynthetic peptide (H492E variant 475-502)
87Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val Ala 1
5 10 15 Phe Glu Arg Ser Ser Ser Glu Lys Ile His Ser Asn 20 25
8828PRTartificial sequencesynthetic peptide (S494K variant 475-502)
88Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Lys Ser Ser Glu Lys Ile His Ser Asn 20 25
8928PRTartificial sequencesynthetic peptide (S496K variant 475-502)
89Ser Pro Val Tyr Val Gly Asn Gly Val His Ala Asn Leu His Val Ala 1
5 10 15 Phe His Arg Ser Ser Lys Glu Lys Ile His Ser Asn 20 25
9028PRTartificial sequencesynthetic peptide
(Y478T/A490G/H492E/S494K/ S496K variant 475-502) 90Ser Pro Val Thr
Val Gly Asn Gly Val His Ala Asn Leu His Val Gly 1 5 10 15 Phe Glu
Arg Lys Ser Lys Glu Lys Ile His Ser Asn 20 25 919PRTartificial
sequencesynthetic peptide (DTR1 478-486) 91Tyr Val Gly Asn Gly Val
His Ala Asn 1 5 929PRTartificial sequencesynthetic peptide (DTR1
491-499) 92Phe His Arg Ser Ser Ser Glu Lys Ile 1 5 939PRTartificial
sequencesynthetic peptide (DTR1 477-485) 93Val Tyr Val Gly Asn Gly
Val His Ala 1 5 949PRTartificial sequencesynthetic peptide (DTR1
487-495) 94Leu His Val Ala Phe His Arg Ser Ser 1 5 959PRTartificial
sequencesynthetic peptide (V483D variant 478-486) 95Tyr Val Gly Asn
Gly Asp His Ala Asn 1 5 969PRTartificial sequencesynthetic peptide
(V483H variant 477-485) 96Val Tyr Val Gly Asn Gly His His Ala 1 5
979PRTartificial sequencesynthetic peptide (V483Q variant 477-485)
97Val Tyr Val Gly Asn Gly Gln His Ala 1 5 989PRTartificial
sequencesynthetic peptide (V483Q variant 478-486) 98Tyr Val Gly Asn
Gly Gln His Ala Asn 1 5 999PRTartificial sequencesynthetic peptide
(A490G variant 487-495) 99Leu His Val Gly Phe His Arg Ser Ser 1 5
1008PRTartificial sequencesynthetic peptide (H492E variant 491-499)
100Phe Glu Arg Ser Ser Ser Glu Lys 1 5 1019PRTartificial
sequencesynthetic peptide (H492E variant 487-495) 101Leu His Val
Ala Phe Glu Arg Ser Ser 1 5 1029PRTartificial sequencesynthetic
peptide (S494K variant 491-499) 102Phe His Arg Lys Ser Ser Glu Lys
Ile 1 5 1039PRTartificial sequencesynthetic peptide (S494K variant
487-495) 103Leu His Val Ala Phe His Arg Lys Ser 1 5
1049PRTartificial sequencesynthetic peptide (S494K variant 489-497)
104Val Ala Phe His Arg Lys Ser Ser Glu 1 5 1059PRTartificial
sequencesynthetic peptide (S496K variant 491-499) 105Phe His Arg
Ser Ser Lys Glu Lys Ile 1 5 10615PRTartificial sequencesynthetic
peptide (DTR1 506-520) 106Ser Asp Ser Ile Gly Val Leu Gly Tyr Gln
Lys Thr Val Asp His 1 5 10 15 10715PRTartificial sequencesynthetic
peptide (T517D variant 506-520) 107Ser Asp Ser Ile Gly Val Leu Gly
Tyr Gln Lys Asp Val Asp His 1 5 10 15 10815PRTartificial
sequencesynthetic peptide (T517E variant 506-520) 108Ser Asp Ser
Ile Gly Val Leu Gly Tyr Gln Lys Glu Val Asp His 1 5 10 15
1099PRTartificial sequencesynthetic peptide (DTR1 512-520) 109Leu
Gly Tyr Gln Lys Thr Val Asp His 1 5
* * * * *
References