Fig. 3.

Immunogenicity of loop-swapped HPV33/58 chimeric VLPs. a Neutralization titers of immune sera from BALB/c mice (n = 5) collected four weeks after the third immunization (immunization at weeks 0, 2 and 4 with 5 μg per dose of aluminum adjuvant-containing chimeric or WT VLPs). A group of mice immunized with mixed WT HPV33 and HPV58 VLPs was labeled. (*) denotes significant differences as compared with the neutralization titer induced by the corresponding backbone type. b Groups of mice (n = 6) were immunized with 0.1, 1 or 10 μg per dose of the selected chimeric or WT HPV33/58 VLPs at weeks 0, 2 and 4. Immune sera were collected at week 8 and analyzed by neutralization assays. All the data were analyzed by one-way analysis of variance (ANOVA), **P < 0.01; ***P < 0.001; ****P < 0.0001. The error bars are standard deviation and symbols represent individual mice. The dotted line indicates the limit of detection for the assay. Non-neutralizing sera were assigned a value of one-half of the limit of detection for visualization