Potency tests for hepatitis B virus vaccines in laboratory animals

The production of a vaccine for use in humans using the plasma of persistent hepatitis-B virus antigen carriers is a recent development in preventive medicine. This new approach requires strict regulations as to quality control. One of these aspects is the immunogenicity of the vaccine that can be tested in laboratory animals, in which the anti-HBs formation is considered through average titre determinations or through an ED 50 test for seroconversion. Both these determinations performed on mice, chickens and guinea-pigs show that ED 50 determinations in mice yield results which are easiest to interpret and that the results obtained in various animal species do not always run parallel. Standardization problems arise with respect to average titre determinations. Our data indicate that in animal sera the titre cannot unequivocally be compared using parallel line bio-assay with a human HBIG preparation.