FIG. 6.

Replication of fully competent HIV-1 particles is augmented by ICAM-1 incorporation through interactions between ICAM-1 and LFA-1. PM1 cells (A), PBMCs (B), and purified CD4⁺ T lymphocytes (C) were left untreated (w/o) or were treated with MEM30, SIM.2, or SDF-1. The cells were then incubated at 37°C for 60 min with similar amounts of isogenic NL4-3 particles either bearing or not bearing ICAM-1 (10 ng of p24). The cells were trypsinized to remove uninternalized virus and were resuspended in complete culture medium. After 48 h, cell supernatants were collected and virus production was estimated by assessing p24 production. Experiments were performed in triplicate, and standard deviations are indicated. The data shown are representative of three separate experiments. The asterisks indicate a significant difference from cells infected with the listed virus preparations and left untreated (*, P < 0.05; **, P < 0.025).