Study shows immune cells -- not HIV particles -- cause AIDS
HIV can attack the host via a free-floating virus that infects the host’s immune cells directly, or infect a single cell and then pass the virus from cell to cell, which is called cell-to-cell transmission.
Cell-to-cell transmission is a more efficient way for the virus to invade a host. It also triggers a cellular chain reaction that causes newly infected cells to commit suicide.
"The fundamental 'killing units' of CD4 T-cells in lymphoid tissues are other infected cells, not the free virus," Gilad Doitsh, a staff research investigator at the Gladstone Institute of Virology and Immunology, said. "And cell-to-cell transmission of HIV is required for activation of the main HIV death pathway."
Large quantities of CD4 T-cell deaths have consequences for the rest of the body.
"Although free-floating viruses establish the initial infection, it is the subsequent cell-to-cell spread of HIV that causes massive CD4 T cell death," Nicole Galloway, a post-doctoral fellow at the Gladstone Institute of Virology and Immunology, said. "Cell-to-cell transmission of HIV is absolutely required for activation of the pathogenic HIV cell-death pathway."
This is important as it could change AIDS treatments in the future.
"This study fundamentally changes our mindset about how HIV causes massive cell death, and puts the spotlight squarely on the infected cells in lymphoid tissues rather than the free virus," Warner C. Greene, director of the Gladstone Institute of Virology and Immunology, said. "By preventing cell-to-cell transmission, we may able to block the death pathway and stop the progression from HIV infection to AIDS."