Perspectives on the role of CD8+ cell suppressor factors and cytotoxic T lymphocytes during HIV infection.

It is clear that HIV burden drives CD8+ cell expansion and activation in vivo, but it has been difficult to determine whether the CD8+ cell response represents a significant anti-HIV force during the natural history of infection. This issue is illustrated by the fact that CD8+ cells cannot clear HIV infection, providing less than satisfactory evidence that CD8+ cells have any substantial effect on viral replication in vivo. The diligent efforts of a number of laboratories, however, are revealing the magnitude of the anti-HIV CD8+ cell arsenal. It is now well established that CD8+ cells can suppress viral dissemination and rates of HIV transcription in addition to their ability to destroy virus-infected cells directly. This is achieved through production of a growing family of HIV suppressor factors. These exciting developments are paving the way for new studies to readdress and potentially redefine the role of HIV-specific CD8+ cell responses during HIV infection. As we complete our understanding of how these effector activities work in concert to oppose HIV, the potential that CD8+ cell responses can be manipulated by vaccination or used in conjunction with HAART holds promise in the ongoing effort to eradicate HIV infection in chronically infected individuals.