FIG 1.

FPC-HPV16 assemble correctly. (A) HPV16 and FPC-HPV16 particles were analyzed by electron microscopy after negative staining. Depicted are representative images of virions. Bars, 100 nm. (B) HPV16 and FPC-HPV16 particle composition by SDS-PAGE and Coomassie blue staining. Note the shift in the size of the furin-cleaved L2 protein (L2 cut). (C) Surface epitopes of HPV16-GFP (black) and FPC-HPV16-GFP (white) particles were targeted with neutralizing antibody H16.V5 (left) or H16.U4 (middle) or nonneutralizing control antibody CAMVIR-1 (right) at indicated dilutions. Presented are infection values (relative proportion of GFP-expressing cells) in HeLa cells relative to untreated controls in percentages ± standard deviations (SD). (D) Dependence on furin of HPV16 (black) or FPC-HPV16 (white) infection was tested in the presence of 10 μM furin inhibitor Dec-RVKR-CMK or, as a control, dimethyl sulfoxide (DMSO). Depicted are infection values relative to DMSO-treated controls in percentages ± SD. (E) To analyze structural processing, HPV16 or FPC-HPV16 and the L2-neutralizing RG-1 antibody were added to HeLa cells. Depicted are infection values relative to mouse serum-treated controls in percentages ± SD.