THP-1/CD169 cells recapitulate mature DC-mediated HIV-1 capture, trafficking and trans-infection of CD4⁺ T cells.

<p>(A) Cells incubated with HIV-1 particles were lysed, and cell lysates used for measuring cell-associated p24^gag. The data shown are the mean percent of captured p24^gag (virus) ± SEM of independent experiments performed in triplicates (n = 3 for DC, n = 5 for THP-1, n = 3 for Raji and HeLa). (B) CD169 expressing cell lines and mature DCs were incubated with Gag-mCherry VLPs and stained for plasma membrane bound CD169 (Surface, top panel) or total CD169 (+ Tx100, bottom panel). CD169 (green), Gag-mCherry VLP (red) and nucleus (blue). Representative deconvolved images of single slices of cells are shown. Scale bars represent 5 μm. (C) Cells incubated with HIV-1 particles were co-cultured with CD4⁺ T cells to monitor HIV-1 trans-infection. Cells were lysed two days post initiation of co-culture and lysates used for measurement of luciferase activity. Values were normalized to luciferase activity observed in control cells (immature DCs or CD169^low/null control cell lines). The data shown are the means ± SEM of independent experiments performed in triplicates with CD4⁺ T cells from different donors (n = 3 for DC, n = 4 for THP-1, n = 3 for Raji and n = 4 for HeLa).