Researchers from the Gladstone Institutes have revealed that HIV does not cause AIDS by the virus’s direct effect on the host’s immune cells, but rather through the cells’ lethal influence on one another.
HIV can either be spread through free-floating virus that directly infect the host immune cells or an infected cell can pass the virus to an uninfected cell. The second method, cell to cell transmission, is 100 to 1000 times more efficient, and the new study shows that it is only this method that sets off a cellular chain reaction that ends in the newly infected cells committing suicide.
“The fundamental ‘killing units’ of CD4 T cells in lymphoid tissues are other infected cells, not the free virus,” says co-first author Gilad Doitsh, PhD, a staff research investigator at the Gladstone Institute of Virology and Immunology. “And cell-to-cell transmission of HIV is required for activation of the main HIV death pathway.”