Immunization with Virus-Like Particle of Human Papillomavirus Type 16 L1 Elicits CTL Immune Response in C57BL/6 Mice

The development of a human papillomavirus vaccine has received a lot of recent attentiondue to the connection between HPV infections and cervical cancer. One promising vaccine to prevent HPV infections is an HPV virus-like particle, and various studies have already shown that HPV VLP immunization elicits a humoral immune response. However, cell mediated immunity is important for the prevention of HPV infections and cancer therapy. Therefore, to check the elicitation of a CTL response by yeast-derived virus- like particles consisting of the HPV16 capsid protein L1, HPV16 L1 VLPs were produced and purified, then C57BL/6 mice immunized with the HPV16 L1 VLPs by subcutaneous injection. Thereafter, the splenocytes from the immunized mice were isolated and a chromium release assay performed using recombinant B16/HPV16 L1cells constantly expressing the HPV16 L1 protein. As a result, the data demonstrated that the T cells from the HPV16 L1 VLP immunized mice exhibited a significantly higher cytotoxic T lymphocyte activity against the recombinant B16/HPV16 L1 cells than the T cells from the PBS immunized control mice.