Hepatitis B vaccine containing surface antigen and selected preS1 and preS2 sequences. 1. Safety and immunogenicity in young, healthy adults

The safety and immunogenicity of a yeast-derived recombinant hepatitis B virus (HBV) vaccine containing surface antigen (S) and selected preS1 and preS2 sequences (S-L∗) were compared with those of a vaccine prepared with S alone (Engerix™-B). S-L∗ consisted of composite particles containing S and L∗ at a ratio of 7030. L∗ encompassed amino acid residues 12–52 of preS1 residues 133–145 of preS2, and the entire S domain. A total of 100 healthy, HBV-seronegative, young adults were randomized to receive 20 μg/dose of either S-L∗ or Engerix™-B under double-blind conditions according to a 0-, 1-, 2-, 12-month schedule. In vivo humoral and in vitro lymphopro-liferative responses to S and preS regions were monitored. Addition of the selected preS sequences to S did not enhance the in vivo humoral anti-HBs response but improved the in vitro stimulating capacity of the antigen (L∗) in S-L∗ primed subjects.