Innate immune activation in primary HIV-1 infection.

There is growing evidence that highlights the role of the immune response during acute human immunodeficiency virus type 1 (HIV-1) infection in the control or development of disease. The adaptive immune responses do not appear until after HIV-1 infection is already well established, so the role of earlier and faster-responding innate immunity needs to be more closely scrutinized. In particular, 2 aspects of innate immunity for which there are growing research developments will be examined in this review: the actions of type I interferons and natural killer cells. These two components of the innate immune response contribute to viral control both by killing infected cells and by modulating other immune cells that develop. However, the role of interferon α in immune activation is a double-edged sword, causing recruitment of adaptive immune cells that can assist in viral control but concurrently contributing to immune activation-dependent disease progression. Understanding the complexity of how innate responses affect the outcome of HIV-1 infection will help in the development of vaccines that can use innate immunity to enhance viral control with minimal pathogenesis.