Dissociated antibody responses to the S and pre S2 regions of the hepatitis B virus after vaccination in hemophiliacs

The membranes of hepatocytes and the pre-S2 envelope protein of the hepatitis B virus (HBV) contain binding sites for polymerized human albumin, which is thought to act as a link between HBV and hepatocytes. Hence, anti-pre-S2 antibodies should prevent HBV uptake by the liver, and there is indeed preliminary evidence that they protect chimpanzees from HBV infection. To evaluate whether a plasma-derived vaccine containing the pre-S2 sequence induced an anti-pre-S2 response in 105 vaccinated hemophiliacs, anti-pre-S2 was measured in parallel with antibody to hepatitis B surface antigen (anti-HBs). Eighty-five percent of the hemophiliacs had both anti-pre-S2 and anti-HBs when vaccination was completed, 13% had anti-HBs alone, and 2% (two cases) had anti-pre-S2 alone. Eighty-seven percent of anti-pre-S2-positive hemophiliacs compared with only 50% of anti-pre-S2-negative hemophiliacs (P < 0.001) developed high anti-HBs titers (≥ 1,000 mlU/ml). This study demonstrates, therefore, that the antibody responses to the S and pre-S2 regions of HBV may be dissociated after vaccination in hemophiliacs and that higher anti-HBs titers are attained in anti-pre-S2-positive hemophiliacs.