Interaction Between HIV and Platelets

The investigators propose that the lack of immune response in InR is driven by HIV-containing platelets that might interact with macrophages and CD4+ T-cells although by different mechanisms. In the one hand, HIV-sheltering platelets might fuel tissue HIV macrophage and in turn T cell reservoirs as observed in InRs and/or maintain a low-level viral replication in macrophages, sustaining a persistent inflammatory profile on in these cells. In the other hand,HIV-sheltering platelets might induce CD4+ T-cells dysfunctions via platelets/ectosomes, although without promoting platelet-to-T-cell HIV transfer/infection, thereby increasing the number of peripheral inflammatory TH17 cells and a TH17/Treg unbalance as observed in InRs. Main Objectives: i) To characterize and the molecular and functional level the platelet factors implicated in HIV transfer to tissue-like macrophages as well as in the immunomodulatory activity of HIV-containing platelets on macrophages and CD4+ T-cells. ii) To interrogate the transfer of HIV-containing platelet-derived mRNA and microRNA to tissue-like macrophages and CD4+ T-cells as one major mechanism of target cell immunomodulation. iii) To investigate the therapeutic potential of anti-platelet aggregation/activation agents (e.g. Abciximab), known to block platelet-immune cell interaction, in improving immune cell functions in vitro and promoting immunological recovery in vivo.