Regulation of Retroviral Infections / Research / Research groups / Host determinants of protection against AIDS

Unité de Régulation des Infections Rétrovirales

Host determinants of protection against AIDS

Béatrice Jacquelin, PhD
Mickaël Ploquin, PhD
Simon Jochems

We are studying the infection by a simian lentivirus (SIV) in African Green monkeys (AGM) as a model for natural protection against AIDS. Our previous data revealed a high replication of SIVagm in these monkeys, both in blood and the intestine, indicating that virus replication is necessary but not sufficient to induce CD4 T cell depletion. In the same line, data of the literature show that the CD4 T cell depletion in HIV-infected humans is only indirectly associated with viral load, but directly with T cell activation levels. We have shown that chronically infected AGMs do not show increased T cell activation despite high viremia levels. By performing a kinetic study starting from day 1 post-infection in blood and lymph nodes, we demonstrate that AGMs are able to control T cell activation very early on after infection. This control is associated with a lack induction of pro-inflammatory cytokines during the acute phase of infection. We are currently investigating the role of innate immunity and of regulatory T cells in the control of T cell activation. These studies are conducted using classical (flow cytometry, real time PCR...) and global approaches (microarrays).