The number of persons living with HIV-1 is around 35 million while roughly one million persons are living with HIV-2, with a decreasing prevalence. Both HIV-1 and HIV-2 are associated with AIDS, however most HIV-2 infected individuals can control the virus replication and maintain undetectable levels of viremia. The results generated by Dr. Saez-Cirion laboratory and others strongly suggest that “natural” HIV-1 controllers – a very rare phenotype- can contain virus replication through cytotoxic HIV-1 specific CD8 T cells in absence of antiretroviral treatment. However little is known on the role of CD8+ T cells to control HIV-2. In the context of the ANRS Immunovir2 study the team aims to understand the mechanisms of natural HIV-2 control and whether they may share similar characteristics to those found in HIV-1 controllers. The results of this study may help understanding the type of responses needed to control HIV disease progression and ultimately lead to the development of efficient immunotherapies to achieve remission.