Drug – bio-affecting and body treating compositions – Antigen – epitope – or other immunospecific immunoeffector – Amino acid sequence disclosed in whole or in part; or...
Reexamination Certificate
2000-07-27
2003-05-06
Mosher, Mary E. (Department: 1648)
Drug, bio-affecting and body treating compositions
Antigen, epitope, or other immunospecific immunoeffector
Amino acid sequence disclosed in whole or in part; or...
C424S192100, C424S196110, C424S197110, C424S211100, C435S320100, C536S023400, C514S04400A
Reexamination Certificate
active
06558673
ABSTRACT:
FIELD OF THE INVENTION
RSV is the most frequent cause of the hospitalization of unweaned infants under one year old for acute respiratory infections. Infants suffering from laryngotracheobronchites, bronchiolites and pneumonias require hospital care, and the incidence of mortality in unweaned infants exhibiting congenital cardiac diseases is greater than 37%. Other disorders such as bronchopulmonary dysplasias, renal diseases and immunodeficiency are equally much factors which are responsible for increased mortality. Infections with RSV can also be a cause of death in old people.
BACKGROUND OF THE INVENTION
In temperate countries, the RSV epidemic occurs during the winter period from November to April, and the highest incidence of serious diseases is found in the unweaned infant of 2 to 6 months. A distinction is made between two types of RSV, RSV-A and RSV-B, on the basis of the antigenic variation of the G glycoprotein of RSV: subgroup A and subgroup B, which circulate concurrently. A recent study which was carried out in France from 1982 to 1990 demonstrated the alternation of one subgroup with the other over a period of 5 years. Strain A is often the cause of infections which are more serious than those caused by strain B.
In the 1960's, an unsuccessful attempt was made to develop conventional vaccines, that is using formolinactivated RSV, in analogy with anti-measles vaccines. Instead of conferring protection on the vaccinated infant, this type of vaccine had the effect of potentiating the natural viral disease.
Human RSV belongs to the genus pneumovirus, which is a member of the Paramyxoviridae family. The genome of the virus consists of an RNA strand which is of negative polarity, is nonsegmented and encodes 10 distinct proteins: NS1, NS2, N, P, M, SH (or 1A), G, F, M2 (or 22K) and L.
Numerous published experiments have demonstrated that the main proteins involved in protection are: F, G and N. The fusion glycoprotein F, which is synthesized as precursor F
0
, is cleaved into two subunits F1 (48 kDa) and F2 (20 kDa) which are bound together by disulphide bridges. The F protein is conserved between RSV-A and RSV-B (91% homology). Conversely, the attachment glycoprotein G varies greatly from one subgroup to the other. Only one region of 13 amino acids (aa 164 to aa 176) is highly conserved and four cysteine residues (173, 176, 182 and 186) are preserved in each subgroup. It has been shown in animal models that the two glycoproteins F and G play a major role in the immunology of RSV. Monoclonal antibodies directed against G and F are able to neutralize the virus in vitro and, when administered passively, they protect the cotton rat from RSV infection.
Current treatments for aggravation of the disease caused by RSV in unweaned infants are clearing the respiratory tract of congestion by aspirating mucus and respiratory assistance provided by ventilation. An antiviral agent, ribavirin, appears to be effective in seriously affected cases. However, its use in paediatric therapy is still poorly defined. Passive immunization with anti-RSV immunoglobulins represents an alternative route in the treatment of serious RSV infections: no undesirable side-effect has been observed. Nevertheless, this type of treatment is very costly and difficult to extrapolate to a large scale.
Different approaches have been taken to vaccinating against human RSV: either the vaccine protects against RSV infection in animals (rodents and primates) but induces pulmonary pathology or else the vaccine is not sufficiently immunogenic and does not provide protection (Connors et al., Vaccine 1992; 10: 475-484).
BRIEF SUMMARY OF THE INVENTION
For this reason, the present invention relates to a process for improving the immunogenicity of an immunogen, in particular an antigen, or a hapten, when it is administered to a host, independently of the mode of administration, characterized in that the said immunogen or hapten is coupled covalently to a support molecule in order to form a complex, and in that this support molecule is a polypeptide fragment which is able to bind specifically to Tmaimalian serum albumin.
Administration can, in particular, take place enterally, parenterally or orally.
The immunogenicity of the complex between the immunogen and the support molecule is found to be improved as compared with that of the immunogen alone, in the absence of any other immunostimulant.
A complex which is particularly suitable for implementing the present invention is obtained by using a conjugate with a polypeptide which is derived from the G protein of Streptococcus; this protein has been characterized by Nygren et al. (J. Mol. Recognit. 1988; 1:69-74).
The invention relates to a process in which the support molecule exhibits the amino acid sequence denoted sequence ID No: 74 or a sequence which exhibits at least 80%, and preferably at least 90%, homology with the said sequence ID No: 74.
This sequence can be attached to linking sequences which promote its expression in a host.
According to the invention, use can also be made of a support molecule which exhibits one of the sequences ID No: 75 or No: 78, as well as of molecules which exhibit at least 80%, and preferably at least 90%, homology with the said sequences.
The peptide sequence ID No: 78 exhibits the following characteristics:
Sequence ID No: 78
Molecular weight: 26529
Gly: 10 (4.08%);
Ala: 30 (12.24%);
Ser: 14 (6.12%);
Thr: 16 (6.53%);
Val: 20 (8.16%);
Leu: 23 (9.39%);
Ile: 12 (4.90%);
Pro: 4 (1.63%);
Cys: 0 (0.00%);
Met: 1 (0.41%);
His: 2 (0.82%);
Tyr: 9 (3.67%);
Asp: 19 (7.76%);
Glu: 19 (8.16%);
Lys: 27 (11.02%);
Arg: 5 (2.04%);
Asn: 16 (6.94%);
Gln: 8 (3.27%);
Phe: 7 (2.86%);
The complex between the support molecule and the compound whose immunogenicity it is desired to improve can be produced by recombinant DNA techniques, in particular by inserting or fusing the DNA encoding the immunogen or hapten into the DNA molecule encoding the support.
According to another embodiment, the covalent coupling between the support molecule and the immunogen is effected chemically using techniques known to the person skilled in the art.
The invention also relates to a gene fusion which renders it possible to implement the process for improving the immunogenicity, characterized in that it comprises a hybrid DNA molecule which is produced by inserting or fusing the DNA encoding the immunogen or hapten into the DNA molecule encoding the support molecule and which is fused with a promoter; the invention also comprises a vector which contains such a gene, it being possible for the said vector to have, in particular, as its origin a DNA vector which derives from a plasmid, a bacterio-phage, a virus and/or a cosmid.
A vector which exhibits the sequence ID No: 76 or 77 belongs to the invention, as does the corresponding polypeptide. These polypeptides exhibit the following characteristics:
Sequence ID No: 76
Molecular weight: 38681
Gly: 11 (3.15%);
Ala: 31 (8.88%);
Ser: 18 (5.16%);
Thr: 37 (10.60%);
Val: 25 (7.16%);
Leu: 23 (6.59%);
Ile: 15 (4.30%);
Pro: 19 (5.44%);
Cys: 4 (1.15%);
Met: 2 (0.57%);
His: 4 (1.15%);
Tyr: 9 (2.58%);
Asp: 22 (6.30%);
Glu: 22 (6.30%);
Lys: 48 (13.75%);
Arg: 7 (2.01%);
Asn: 26 (7.45%);
Gln: 13 (3.72%);
Phe: 12 (3.44%);
Trp: 1 (0.29%);
Sequence ID No: 77
Molecular weight: 39288
Gly: 12 (3.37%);
Ala: 31 (8.71%);
Ser: 22 (6.18%);
Thr: 37 (10.39%);
Val: 26 (7.30%);
Leu: 23 (6.46%);
Ile: 15 (4.21%);
Pro: 21 (5.90%);
Cys: 2 (0.56%);
Met: 2 (0.56%);
His: 4 (1.12%);
Tyr: 9 (2.53%);
Asp: 23 (6.46%);
Glu: 22 (6.18%);
Lys: 48 (13.48%);
Arg: 7 (1.97%);
Asn: 26 (7.30%);
Gln: 13 (3.65%);
Phe: 12 (3.37%);
Trp: 1 (0.28%);
The DNA molecule which encodes the complex between the immunogen and the support molecule can be integrated into the genome of the host cell.
In one of its embodiments, the novel process includes a step for producing the complex, by genetic manipulation, in a host cell.
The host cell can be of the prokaryote type and be selected, in particular, from the group comprising:
E. coli
, Bacillus, Lactobacillus, Staphylococcus and Streptococcus;
Andreoni Christine
Binz Hans
Ngoc Nguyen Thien
Nygren Ake Per
Stahl Stefan
Mosher Mary E.
Pierre Fabre Medicament
Wood Phillips Katz Clark & Mortimer
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