Fig. 4.

Immunogenicity of loop-swapped HPV33/58/52 chimeric VLPs. a Schematic representation of the chimeric HPV33/52/58 L1 proteins based on chimeric L1 proteins H33-58HI and H58-33BC. A group of mice were immunized with mixed WT HPV33, -52 and -58 VLPs. b Neutralization titers of the immune sera from BALB/c mice (n = 4) collected 4 weeks after the third immunization (immunization at weeks 0, 2 and 4 with 5 μg per dose of aluminum adjuvant-containing tripe-type chimeric or WT VLPs). All the data were analyzed by one-way 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