Subtype specificity of anti-HBs antibodies produced by human B-cell lines isolated from normal individuals vaccinated with recombinant hepatitis B vaccine

Hepatitis B surface antigen (HBsAg) constitutes of an immunodominant determinant common to all subtypes of hepatitis B virus (HBV) and four major subtypic determinants. Subtype specificity of the human antibody response to HBsAg has already been partially studied in vivo at serum level. No comprehensive data, however, is available at the cellular level. In this study, the methods of Epstein-Barr virus (EBV) transformation and limiting dilution assay (LDA) were used to establish a large number of B-cell lines secreting anti-HBs antibody from 34 adult individuals who were good-responders to the recombinant hepatitis B vaccine (HBsAg/adw). Specificity of 222 B-cell lines was assayed by sandwich ELISA and immunoblotting, of which 216 samples (97.3%) were identified to be anti-a, 5 samples (2.3%) as anti-d and one sample (0.4%) as anti-w. The isotype of most of the anti-HBs antibodies was IgG and belonged to the IgG1 subclass. These findings which have not already been extensively investigated at the cellular level in human confirm and extend previous circumstantial results achieved in mouse and further prove the immunodominant role of the “a” determinant of HBsAg in antibody response in human.