FIG. 6.

Cytosine arabinoside (AraC) treatment reduces cell surface expression of gp120. HeLa cells infected with HXB2 gp160-expressing vaccinia virus were cultured in the presence of various concentrations of cytosine arabinoside and analyzed for surface expression. (A) Western blot detection of biotinylated gp120. Cells infected with HXB2 gp160-expressing vaccinia virus in the presence of the indicated concentrations of AraC were treated with the membrane-impermeant biotinylation reagent sulfo-NHS-LC-biotin, lysed, and immunoprecipitated with NHS (right) or serum from HIV-infected subjects (HIVIG, left). Biotinylated proteins were resolved by SDS-PAGE, transferred to nitrocellulose, and detected with horseradish peroxidase-conjugated streptavidin. (B) Cells were prepared as described for panel A but were grown in glass chamber slides and were stained with a phycoerythrin-conjugated anti-gp120 monoclonal antibody.