FIG. 5.

Blockade of T-cell-mediated macrophage activation and IFN-γ production in vitro by anti-LFA-1 MAb. Bone marrow macrophages from TNFR-deficient or wild-type mice were cultured with T cells and anti-CD3 (5 μg/ml) in the presence of anti-LFA-1 (10 μg/ml), anti-ICAM-1 (10 μg/ml), or control rat IgG (10 μg/ml) for 72 h. Nitrites were measured as in Fig. 1. The data shows the mean NO₂ levels (±SE) of one experiment with TNFRp55p75^−/− macrophages, TNFRp55^−/− macrophages, and wild-type macrophages after 72 h of incubation. The experiment was repeated three times, with similar results. Student's paired t test indicated that NO production was significantly less (P < 0.05) for all macrophages incubated with anti-LFA-1 but not for those incubated with anti-ICAM-1.