HEPATITIS-B VIRUS (HBV)-SPECIFIC IN-VITRO ANTIBODY-PRODUCTION BY PERIPHERAL-BLOOD MONONUCLEAR-CELLS (PBMC) AFTER VACCINATION BY RECOMBINANTHEPATITIS-B SURFACE-ANTIGEN (RHBSAG)

To study the immunization induced by rHBsAg, we analysed the in vitro antibody production (IVAP) to HBsAg by PBMC from 18 subjects vaccinate d by two injections on days 0 and 30. HBsAg-specific IVAP was detectab le in all subjects after both the first and the second injection, and lasted for about 10 days and then disappeared. However, when the spont aneous HBsAg-specific IVAP became negative, HBsAg stimulation of PBMC cultures induced again a specific HBsAg IVAP. Cultures of cell populat ions separated by erythrocyte resetting or Percoll density centrifugat ion showed that the cells responsible for spontaneous secretion, after in vivo stimulation, were low-density B lymphocytes. High-density B l ymphocytes were involved in anti-HBs production induced by in vitro st imulation when spontaneous secretion disappeared. These data suggest t hat the IVAP test could be a source of important information along wit h serologic analysis for exploration of the immune response to hepatit is B vaccine.