L1-specific protection from tumor challenge elicited by HPV16 virus-like particles.

A single injection of HPV16 L1 virus-like particles induced potent CD8-mediated protection from tumor challenge by C3 cells, a line derived from embryonic mouse cells transfected with the HPV16 genome. L1 RNA, but not protein, was detected biochemically in C3 cells. These results indicate that low-level expression of HPV16 L1 can occur in proliferating cells and serve as a tumor vaccine target. Although L1 expression is generally thought to be restricted to terminally differentiated epithelial cells, these results suggest that additional analysis for low-level L1 expression in proliferating cells of HPV-induced lesions is warranted and might help in predicting the clinical potential of HPV L1 virus-like particle-based vaccines.