FIG 2.
The block to HIV infection in P. alecto cell is dominant but not saturable. (A) Heterokaryon infection. The indicated cells were cocultured for 24 h prior to fusion performed with polyethylene glycol (PEG 500) or control treatment with PBS. Levels of fusion efficiency were verified to be equivalent by counting multinucleated cells. At 24 h postfusion, cells were infected with R5 HIV-1, and after an additional 48 h, cells were counted and analyzed for luminescence. The experiment was repeated four times with the same results. (B) Inability of VLPs to abrogate the block in P. alecto cells. Cells were first infected with VLPs (VSV-G-pseudotyped HIV-1 particles with no viral genome). At 30 min later, the cells were infected with HIV-1LTR-luc(VSV-G). Four days after infection, the cells were counted and analyzed for luminescence. Error bars represent the standard deviations of luminescence data calculated in triplicate. This experiment was repeated three times with the same results. *, P < 0.01.