Figure 2. Pathways of recognition of HIV-infected cells by hematopoïetic cells.

a. Effect of drugs targeting endosomal TLR signaling or HIV reverse transcription in PBMCs. PBMCs were cocultivated with HIV-infected MT4C5 cells, exposed to FLUAV, or to CpG (a TLR9 agonist) during 12 h, in the absence or presence of the indicated drugs. NVP (25 µM) is a reverse transcriptase inhibitor. Bafilomycin A1 (Bafilo, 125 nM) is an inhibitor of vesicular acidification. A151 (5 µg/mL) is a TLR antagonist. Nevirapin (NVP 25 µM) is a reverse transcriptase inhibitor. IFN levels are expressed as the % of the signal obtained without drugs. Mean+sd of 3 independent experiments is shown. *p<0.05 (Kruskal-Wallis). b-d. Viral proteins required for the recognition of HIV-expressing cells by PBMCs. b. Schematic representation of the experimental system. HeLa cells are transfected with various HIV mutants, cocultivated with PBMCs, and levels of IFN released in supernatants are measured 22 h later. c. Defective viruses trigger IFN production by PBMCs. HeLa cells were transfected with the indicated proviral mutants. Supernatants were harvested and analyzed for the presence of infectious virus, after normalization for Gag p24 levels. Env-deleted (ΔEnv), non-fusogenic Env (HIV F522Y), reverse transcriptase (RT-), integrase (IN), protease (PR), Rnase H (RH), and nucleocapsid (NC44) mutants are not or poorly infectious (left panel). Levels of IFN in supernatants, after coculture of tranfected HeLa cells with PBMCs. IFN levels are expressed as a percentage of the signal obtained with WT HIV (right panel). d. Expression of Env alone does not trigger IFN production. HeLa-Env cells (stably expressing a functional Env glycoprotein complex) were either not infected (NI) or infected with ΔEnv or WT viruses (pseudotyped with VSV), then processed and analyzed as in c. c-d: Mean+sd of 2-3 independent experiments is shown. *p<0.05 (Kruskal-Wallis).