People who manage to control HIV on their own are providing scientists with valuable information about how the immune system eliminates virus-infected cells.
A new study, published in the December 4th issue of Immunity , a Cell Press publication, identifies specific characteristics of the immune cells that successfully destroy HIV-infected cells and may drive strategies for developing the next generation of HIV vaccines and therapies.
Long-term nonprogressors (LTNPs) or elite controllers are rare individuals who are able to contain HIV for many years without any type of antiretroviral therapy. "Direct and indirect lines of evidence in humans and animal models suggest that virus-specific immune cells, called CD8+ T cells, mediate this control. However, the mechanisms by which this occurs remain unknown," says senior study author Dr. Mark Connors from the National Institute of Allergy and Infectious Disease in Bethesda, Maryland.
Using sophisticated new tools that can precisely measure the killing capacity of HIV-specific CD8+ T cells on a per-cell basis, Dr. Connors and colleagues compared how cells from LTNPs and progressors battle HIV by destroying infected cells. The CD8+ T cells of LTNPs efficiently eliminated infected cells by successfully loading granules with the proteins necessary for poking holes in the membranes of target cells and subsequently delivering a death-inducing molecule called granzyme B to cells infected with HIV.