FIG. 7.

Immunohistochemical and immunofluorescent staining for late viral gene products in organotypic raft cultures. Shown are histological sections of organotypic raft cultures generated with WT and E5 mutant-harboring NIKS cells, or untransfected NIKS cells. For L1 immunohistochemistry, cross sections from each sample were incubated with an anti-L1 antibody (CamVir 1) and detected using the Vectastain ABC Kit. L1-positive cells, staining brown, are indicated by arrows. The sections were counterstained with hematoxylin, which stains nuclei blue. L1 was detected in both the WT (A) and E5 mutant (B) HPV16-positive raft cultures, but not in the untransfected NIKS raft cultures (C). For E1∧E4 immunofluorescence, cross sections from each sample were incubated with an anti-E1∧E4 antibody (TVG-402) and detected using a fluorescent-conjugated secondary antibody (AlexaFluor 488; Molecular Probes). E1∧E4-positive cells are indicated by arrows. The sections were counterstained with DAPI (blue nuclei). The E1∧E4 protein also was detected in both the WT (D) and E5 mutant (E) HPV16-positive NIKS raft cultures but not in untransfected NIKS raft cultures (F).