Neutralization capacity of vaccine-induced anti-HPV L2 antibody responses measured in vivo PsV genital challenge mouse model and in vitro L2-based PsV inhibition assay. Balb/C mice were first immunized and then challenged with HPV PsV, as described in Fig. 1d (top panel). Infection levels in vaccinated mice were measured against non-vaccinated i.e. naïve control mice. Graph shows average radiance for individual mice as well as geometric mean and SD for each group. (a) PsV infection in mice immunized with either the 5xL2-VLP (left panel) vaccine or the 2xL2-VLP vaccine (right panel) (with/without co-display of VAR2CSA) after challenge with HPV PsV16. (b) PsV infection in 5xL2-VLP or 2xL2-VLP immunized mice challenged with HPV PsV31, 35, 45, or 52. (c) Balb/C mice were immunized with 1xL2-VLP, as described in Fig. 1d (lower panel). Neutralization titers (IC50) against HPV PsV 16 and 45 were measured in mouse serum collected 9 weeks after prime vaccination using an in vitro L2-based PsV inhibition assay, as previously described35.