[Experiments for the development of a hepatitis B vaccine: immunogenicity of HBsAg in guinea pigs (author's transl)].

Hepatitis B surface antigen (HBsAg) was purified from human plasma by gel chromatography, isopyknic centrifugation, and zonal centrifugation. The final product had about 60% of the original activity and was essentially free from hepatitis B virus particles (HBV) and plasma proteins. Treatment with formaldehyde concentrations up to 0.1% for inactivation of residual infectivity did not significantly reduce antigenicity in vitro and immunogenicity in guinea pigs. Adsorption to aluminum hydroxide resulted in 16-fold higher concentrations of antibody against HBsAg (anti-HBs) than did injection of soluble HBsAg. After two injections of 0.2 microgram HBsAg, which was treated with 0.1% formaldehyde and absorbed to aluminum hydroxide, the median titer of anti-HBs in guinea pigs was 4 IU/ml (normal value in human hepatitis B convalescents: about 0.1) for 1 year without further injections. When guinea pigs received 12 equivalents of homologous anti-HBs serum before the first injection of adsorbed HBsAg, the same anti-HBs titers were found after the booster injection as in animals which had not been passively immunized. A simultaneous application of an experimental HBsAg vaccine and hepatitis B immunoglobulin would probably decrease the potential risk of HBV infections caused by the vaccine itself and also produce rapid protection. To establish absence of HBV as completely as possible, the vaccine should be produced from anti-HBe-positive plasma by efficient purification procedures and it should be inactivated by formalin.