Kinetics of in vitro adsorption and entry of papillomavirus virions.

There has been much incongruence in reports addressing the rate at which papillomaviruses enter cultured cells. We used a recently developed QRT-PCR assay (J. Virol. Methods 111 (2003) 135) to analyze the expression, adsorption, and entry kinetics of human papillomavirus type 11 (HPV-11) in multiple cell lines. Parallel experiments with HPV-40 and cottontail rabbit papillomavirus (CRPV) were also performed with biologically relevant lines. Infection was determined by the expression of early transcripts containing the E1 E4 splice junction. Results support previous observations that papillomaviruses may enter cultured cells much more slowly than rates reported for similarly structured viruses (Virology 207 (1995) 136; Virology 307 (2003) 1; J. Virol. 75 (2001) 1565). Additionally, our data suggest that, following adsorption to the cell surface, capsomeric structure remains largely unchanged for many hours as HPV-11 virions remain equally susceptible to neutralization by a nonspecific microbicide and by L1-specific monoclonal antibodies (MAb) targeting both linear and conformationally sensitive epitopes.