FIG 4.

HIV activates pDCs to produce FasL. (A) PBMCs were cultured with medium, LPS, HIV (X4), or LPS plus HIV for 24 h. FasL production in the supernatants was measured by enzyme-linked immunosorbent assay (ELISA) in vitro. n = 5. P > 0.05 for a comparison between any two treatments. (B) Representative dot plots displaying the gating strategy used to assess the percentage of FasL⁺ in pDCs from one representative donor. PBMCs were first treated with sCD4 (10 μg/ml), IFNR inhibitor (20 μg/ml), CXCR4 inhibitor (AMD3100; 10 μg/ml), or CCR5 inhibitor (10 μg/ml) for 3 h and then incubated with medium, HIV (X4, 150 ng/ml, or R5, 150 ng/ml), or gp120 (150 ng/ml) for an additional 20 h. The intracellular levels of FasL in pDCs (CD123⁺ BDCA2⁺) were analyzed by flow cytometry. (C) Median frequencies of FasL⁺ pDCs and P values between pairs of conditions. (D) The frequencies of intracellular FasL expression were examined in monocytes (CD14⁺), MDCs (BDCA1/3⁺ CD11c⁺), and pDCs (CD123⁺ BDCA2⁺) from 4 controls and 5 viremic ART-naive HIV⁺ donors in fresh peripheral blood samples ex vivo. (E) Correlation between the percentages of FasL⁺ pDCs and plasma HIV RNA levels. The data are presented as medians.