If the battle against HIV, the virus that causes AIDS, is a chess match, then new research published today gives new insight into one of the virus’ most important moves. The findings reveal information about how a critical genetic switch in the virus operates. When HIV infects an immune cell, it can enter one of two states: activation, where the virus replicates and then destroys the host cell; and latency, where the viral genetic material continues to exist in the cell, but there is no production of additional virus.