Isotype-specific immune response to a single hepatitis C virus core epitope defined by a human monoclonal antibody: diagnostic value and correlation to PCR.
In this study we tested the seroreactivity of 223 selected anti-HCV-reactive blood donors to the human B-cell epitope N-VYLLPR-C (C34-39) of the hepatitis C virus core antigen. The epitope was recently identified and characterized by the human monoclonal IgG antibody Ul/F10 and is located within the amino acid residues 34-39 of the aminoterminal core region. The blood donor sera were selected from anti-HCV ELISA (Ortho, 2nd generation)-reactive samples. Sixty-seven of these sera were further reactive in RIBA (Ortho, 2nd generation). According to their RIBA pattern, these samples were divided into four groups. Samples in the first group (n = 18) reacted to all four recombinant HCV antigens. The samples of the second (n = 9) and third group (n = 8) reacted to c22-3/c33c and c22-3/c100-3, respectively. Sera from group 4 (n = 32) showed a RIBA indeterminate pattern with reactivity only to c22-3. All 223 samples were analyzed for anti-C34-39 antibodies by ELISA, and the 67 RIBA-reactive samples were additionally tested for the presence of HCV RNA by RT/PCR. In groups 1 and 2, over 80% of the samples showed anti-C34-39 reactivity which was restricted to the IgG1 isotype. In contrast, in groups 3 and 4, antibodies to the epitope C34-39 were detected in less than 10% of the samples. Interestingly, the anti-C34-39 response correlates with the presence of HCV RNA; 95.5% of the samples had coincident results in all subgroups. None of the RIBA-negative sera showed a specific seroreaction to the C34-39 peptide.
Siemoneit
K
K
German Red Cross Blood Bank, Ulm.
da Silva Cardoso
M
M
Wölpl
A
A
Epple
S
S
Wintersinger
H
H
Koerner
K
K
Kubanek
B
B
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000956:Antigens, Viral / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology*; D006526:Hepatitis C / Q000175:diagnosis*; D018936:Hepatitis C Antigens; D006801:Humans; D015151:Immunoblotting; D007132:Immunoglobulin Isotypes / Q000276:immunology*; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000032:analysis; D011994:Recombinant Proteins / Q000276:immunology; D014758:Viral Core Proteins / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D018936:Hepatitis C Antigens; D007132:Immunoglobulin Isotypes; D012367:RNA, Viral; D011994:Recombinant Proteins; D014758:Viral Core Proteins; C499352:core protein p22, Hepatitis C virus; C069130:nucleocapsid protein, Hepatitis C virus