(A) Pseudovirion cross-neutralization antibody assay for the HPV16L2-N88 groups (including HPV16L2-N88, PTD-HPV16L2-N88 and PTD: HPV16L2-N88). The animal serum was serially diluted, mixed and incubated with pseudovirion particles to infect cells, and fusion type of PTD significantly increased the titers of cross-neutralizing antibody. However, mixed PTD peptides were less effective, which was similar to the groups without PTD. (B) Pseudovirion cross-neutralization antibody assay for the HPV16L2-N200 group (including HPV16L2-N200, PTD-HPV16L2-N200 and PTD: HPV16L2-N200). The overall titers of the cross-neutralization antibody were higher than those of the HPV16L2-N88 groups. PTD-fused expression significantly improved the titers of the cross-protective antibody in each group. Several mixed types had specific effects. HPV, human papillomavirus; PTD, protein transduction domain.