SUBTYPE SPECIFICITY OF ANTI-HBs ANTIBODIES PRODUCED BY HUMAN B CELL LINES ISOLATED FROM NORMAL INDIVIDUALS VACCINATED WITH RECOMBINANT HEPATITIS B VACCINE

Fazel SHOKRI^1,2, Mohammad Ali SHOKRGOZAR¹

¹National Cell Bank of Iran, Pasteur Institute in Iran

²Department of Immunology, School of Public Health, Teheran University of Medical Sciences, Teheran, IRAN

Serologic examination of hepatitis B virus surface antigen (HbsAg) indicated that HbsAg particle consisted of a common “a” determinant and at least two subdeterminants “d” or “y” and “w” or “r”. Based on these findings four major subtypes of HbsAg namely adw, adr, ayw and ayr have been indentified. Research carried out on the subtypes of HbsAg demonstrate that the “a” determinant consitituted the immunodominant epitope of the above antigen. The antibody produced against the “a” determinant was protective and variations in a single amino acid of this determinant may have a significant effect on its three dimensional conformation leading to loss of antigen recognition by the specific antibody. In this study, the methods of 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 recombinants hepatitis B vaccine (HbsAg/adw). Specificity of 222 B-cell lines was assayed by sandwich ELISA, 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. These results which had not already been reported at the cellular level in human confirmed the previous results achieved in mouse and further proved the immunodominant role of the “a” determinant of HbsAg in antibody response in human.