CORRELATION BETWEEN IN-VIVO HUMORAL AND IN-VITRO CELLULAR IMMUNE-RESPONSES FOLLOWING IMMUNIZATION WITH HEPATITIS-B SURFACE-ANTIGEN (HBSAG) VACCINES

To study the regulation of the human immune response to hepatitis B su rface antigen (HBsAg) we have carefully monitored the in vivo humoral and in vitro cellular immune responses to HBsAg in 50 subjects receivi ng four doses of hepatitis B vaccine according to a 0, I, 2, 12 month vaccination scheme. Twenty-three subjects were given a plasma-derived vaccine (Hevac B) and 27 received a recombinant HBsAg vaccine (yeast-d erived; Engerix-B). The humoral and cellular immune responses were mea sured before vaccination (day 0); 6 days after the second dose (day 36 ); 6 days (day 66), 2 months (day 120) and 10 months (day 365) after t he third dose and 1 month after the fourth dose (day 395). Based on th e kinetics of the humoral immune responses, the vaccinees could be cla ssified into fast, intermediate and slow/non-responders. Based on the magnitude of the immune response (anti-HBs titre) on day 395, the vacc inees could be divided into high (greater than or equal to 2000 Ul(-1) ) and low (less than or equal to 2000 Ul(-1)) responders. A close corr elation between the kinetics and the magnitude of the humoral immune r esponse was observed The in vivo anti-HBs response was measured using commercially available immunoradiometric assays. The in vitro cellular immune response was measured using an HBsAg-specific lymphoproliferat ion assay. Because of interassay variability the results were consider ed as dichotomous variables (proliferation versus non-proliferation) f or further data analysis. A statistically significant correlation was observed between the kinetics and magnitude of the humoral immune resp onse on the one hand and the in vitro anti-HBs response on the other h and. Although this study was not designed to compare the immunogenicit y of a plasma-derived versus a recombinant vaccine, the data show that both vaccines are equally immunogenic. They induced similar seroconve rsion rates and geometric mean titres at all time points evaluated We further demonstrate that female vaccine recipients display a swifter a nd more vigorous anti-HBs response that male vaccinees.