Induction of type-specific neutralizing antibodies by capsomeres of human papillomavirus type 33

The immunogenicity of capsomeres of human papillomavirus type 33 was evalua ted in a dose-response analysis. Capsomeres were obtained free of capsids b y expression of L1 carrying the single point mutation C427S. Neutralizing a ntibodies were detected using an in vitro pseudoinfection assay. Capsomeres induced type-specific, neutralizing antibodies in mice even in the absence of adjuvant. The neutralization titers of immune sera raised without adjuv ant were 10- to 20-fold lower than those of antisera to virus-like particle s, but virtually identical using Freund's adjuvant. These data indicate tha t capsomeres may substitute for virus-like particles in future vaccines whe n used with an adjuvant appropriate for human vaccination. (C) 2001 Academi c Press.