FIG. 4.
Surface molecule downregulation peaks early postinfection, despite persistent viral infection. To determine the time course of downregulation, HeLa cells were infected with KSHV and surface molecule levels were analyzed by flow cytometry at various time points. (A) KSHV-infected HeLa cells were analyzed for MHC-I and ICAM-1 surface levels at 0, 8, 16, 29, 42, and 66 h postinfection. Bars represent the percentages of cells that have downregulated MHC-I (white bars) or ICAM-1 (black bars) in the total cellular population and are from a representative experiment. (B) MHC-I, ICAM-1, and LFA-3 surface expression in HeLa cells 2 and 7 days postinfection. Results from representative experiments with or without PAA are shown; PAA (400 μM) was used to block virion production and subsequent reinfection in culture. Results for isotype antibody controls (solid gray histogram), mock infection (gray histogram), and KSHV infection (black histogram) are shown. (C) Persistence of viral infection was measured by IFA of LANA expression. The total percentage of infected cells (left graph) and average number of LANA dots per cell (right graph) at 2 and 7 days postinfection are shown. Values for cultures in the absence (white bars) and presence (black bars) of PAA are shown (n = 2 ± range).