FIG. 2.

(A) Identifying surfaces recognized by antibodies and required for neutralizing activity by H16.H5. To determine if the VLPs were correctly folded, they were tested in direct binding assays (ELISAs) using MAbs known to recognize the various hybrids. H16.V5 and H16.U4 are HPV16 MAbs that recognize epitopes known to depend on the native conformation of the HPV16 VLPs. H31.A4 is a specific HPV31 MAb that recognizes a conformation-dependent epitope on HPV31 VLPs. (B) H16.V5 was used to inhibit pseudovirus infection following incubation with VLPs. H16.V5 was titrated across a plate, and hybrid or wild-type VLPs were added. The following day, HPV16 pseudovirions were added to each well and incubated on ice for 1 h. Those samples were transferred to a 96-well tissue culture dish seeded with 293TT cells. After 3 days, 30 μl was removed from each well and tested for alkaline phosphatase activity.