Human monoclonal antibodies for the immunological characterization of a highly conserved protein domain of the hepatitis C virus glycoprotein E1.
Although both envelope glycoproteins of the hepatitis C virus, E1 and E2/NS1, show a high degree of sequence variation, the E1 protein includes a well conserved domain, which may be functionally important. We have analysed the human B cell response to a peptide fragment from amino acid residues 314-330 (EP3) covering the central conserved sequence of this domain. Anti-hepatitis C virus-positive blood donors were screened for anti-EP3 antibodies with an ELISA based on immobilized peptide. Thirty out of 92 (32%) RIBA-confirmed donors displayed a significant antibody response to EP3. From three of these blood donors we established four anti-EP3-producing heterohybridoma cell lines: Ul/F30 and Ul/F31 produced IgM-kappa, whereas Ul/F32 and Ul/F33 secreted the isotypes IgG1-lambda and IgG1-kappa, respectively. Epitope analysis with overlapping nonapeptides suggests the existence of different antigenic determinants within the EP3 fragment. Although both IgG antibodies Ul/F32 and Ul/F33 have dissociation constants to the peptide of approximately 10(-9) M, binding to recombinant E1 protein expressed in COS-7 cells was different. Only Ul/F33 detected envelope protein of approximately 24-35 kD in Western blot. This human MoAb will be useful for further investigations on the hepatitis C virus glycoprotein E1.
Siemoneit
K
K
German Red Cross Blood Bank, Ulm.
Cardoso
M da S
Mda S
Koerner
K
K
Wölpl
A
A
Kubanek
B
B
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology; D017124:Conserved Sequence; D006508:Hepatitis Antibodies / Q000097:blood / Q000276:immunology*; D006526:Hepatitis C / Q000097:blood; D018937:Hepatitis C Antibodies; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D014759:Viral Envelope Proteins / Q000276:immunology*
D000911:Antibodies, Monoclonal; C087035:E1 protein, Hepatitis C virus; D006508:Hepatitis Antibodies; D018937:Hepatitis C Antibodies; D007074:Immunoglobulin G; D010446:Peptide Fragments; D014759:Viral Envelope Proteins