Chemistry: natural resins or derivatives; peptides or proteins; – Proteins – i.e. – more than 100 amino acid residues
Patent
1992-12-11
1998-03-31
Woodward, Michael P.
Chemistry: natural resins or derivatives; peptides or proteins;
Proteins, i.e., more than 100 amino acid residues
530826, 435 693, 435 5, 930223, C07K 1418, C12N 1551, G01N 33569
Patent
active
057340196
DESCRIPTION:
BRIEF SUMMARY
DETAILED DESCRIPTION OF THE INVENTION
1. Technical Field
The present invention relates to a novel antigen which is useful in the diagnosis of the hepatitis C and the like and is translated from the structural region of the hepatitis C virus genome, a production method therefor, and a detection method for antibodies associated with hepatitis C using this antigen.
In greater detail, the present invention relates to a novel HCV antigen polypeptide (hereinafter termed "p22") which is a peptide which is coded for in the hepatitis C virus (hereinbelow termed "HCV") structural gene region and which exhibits a molecular weight in SDS-PAGE of roughly 22 kilodaltons, a production method for this HCV antigen polypeptide, and a detection method for antibodies associated with hepatitis C using this polypeptide.
2. Prior Art
HCV has recently been identified as a pathogenic virus causing hepatitis C, which is one type of vital hepatitis. It is characteristic in that it is responsible for almost all cases of hepatitis C occurring after blood transfusions in Japan, and in that it causes not only transient infection but also persistent infection (in Japan, about 1.2% of the population is persistently infected). Approximately half of all cases of acute hepatitis C become chronic, and furthermore, chronic hepatitis may gradually develop into cirrhosis or liver cancer. In addition, the percentage of those who are persistently affected is reported to be from 1-3% of the population worldwide. That is to say, hepatitis C is a grave infectious disease worldwide, and the prevention, early diagnosis, and treatment thereof have global significance.
HCV is a positive strand RNA virus;the virus genome thereof has a size of approximately 10,000 bases. A structural gene region coding for the viral structural protein is located on the 5' side of the genome, and a non-structural (NS) gene region is located downstream from this. No antigen protein coded for by this virus has been identified as yet. The sole measuring method for antigens and antibodies which has been reported to date is an antibody (anti-C100 antibody) detection method for a fusion protein (C100) which is produced in yeast and contains 363 amino acids of a part of the HCV non-structural gene region (a region from NS3 to NS4). Using this antibody detection method, it is possible to determine, to a certain extent, whether a history of exposure to HCV exists, so that this detection method has been used in the diagnosis of the hepatitis C virus. Furthermore, blood which registers positive on this detection test often contains infectious HCV, so that this detection method is presently in use in Japan in the screening of blood to be used in transfusions.
The C100 antibody described above normally takes from 3-6 months to become positive after the infection of hepatitis C virus, so that this method cannot be used as a diagnostic method for hepatitis C during this period, and this has been recognized to be a major problem. Furthermore, even in cases in which only blood which was negative for the anti-C100 antibody was used in blood transfusions, a certain number of occurrences of the hepatitis C virus was noted, so that it is thought that only approximately half of hepatitis cases occurring after blood transfusions could be screened out by using this method alone; there is thus a need for a new antibody test or a detection method for virus structural protein antigens. Furthermore, as the C100 antigen is derived from non-structural protein genes, identification of a virus structural protein and establishment of a detection system for the antigens and the antibodies thereof is extremely important in order to find a more direct diagnostic method or candidates for future vaccines.
As a result of conducting research in order to solve the above problems, the present inventors have expressed the cDNA of the HCV structural gene region in cultured cells, and, by means of the fluorescent antibody technique and the Western blot method using the serum of hepatitis C patients, have discovered a
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Chiba Joe
Harada Shizuko
Matsuura Yoshiharu
Miyamura Tatsuo
Saito Izumu
Chiba Joe
National Institute of Health
Woodward Michael P.
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