"Dendritic cells (DC) are the front-line of virus detection and trigger the response of the innate and adaptive immune system. DCs ""patrol"" in the body and seek pathogens such as viruses. When they catch viruses, they initiate immune responses primarily in lymph nodes and lymphoid tissue. DCs acquire a mature phenotype while they migrate towards the lymphoid tissues in order to process and present the antigens derived from viruses. They also produce various cytokines and chemokines, substances with pro-inflammatory properties. Antigen presentation by DCs can activate the immune system by inducing specific CD4 and CD8 T lymphocytes responses, responsible for destroying the virus. DCs are relatively resistant to infection by HIV. A cell antiviral factor named SAMHD1, was recently identified as protecting DCs and macrophages from productive infection by HIV-1. We want to characterize the SAMHD1 mechanism of action, how and why it protects DCs from HIV infection. HIV infection is mainly achieved by the formation of cellular contact between infected cells and target cells, thus we aim to examine the role of SAMHD1 during these contacts. We will also study the role of SAMHD1 in the induction of the immune response against HIV. This project is in collaboration with the team of Monsef Benkirane, which has recently identified the protein SamHD1, and the team of Yves Levy. We expect to unmask how HIV has evolved to escape from the immune response; a relevant issue to better understand why nowadays treatments have failed to completely eradicate the virus."