HIV does not cause AIDS by affecting the host’s immune cells directly, but more frequently by the host cells’ influence on each other, say researchers from Gladstone Institutes. HIV infection inside the host can take place by two different modes; one is the free-floating virus affecting the host immune cells and the second lethal mode is HIV-infected human immune cells passing virus to the uninfected cells.
The investigators revealed in their study that transmission of virus from infected immune cell to uninfected cell causes AIDS more efficiently than free-floating HIV in the host. They also noted that cell to cell transmission is 100 to 1000 times more efficient in causing AIDS by initiating a cellular chain reaction resulting in suicide of newly infected cells.
Dr Gilad Doitsh, the co-author of the study and a staff research investigator at the Gladstone Institute of Virology and Immunology, said, “The fundamental ‘killing units’ of CD4 T cells in lymphoid tissues are other infected cells, not the free virus.” Doitsh added, “And cell-to-cell transmission of HIV is required for activation of the main HIV death pathway,” according to Infection Control Today.
It was observed by researchers in earlier studies that about 95 percent of cell deaths on HIV infection is caused when the immune cells commit suicide, a self-defense mechanism as a result of unsuccessful infection. But it is established clearly in the new study that the death pathway is turned on only by cell to cell transmission and not by free floating virus.
Nicole Galloway, co-author of the study and a post-doctoral fellow at the Gladstone Institute of Virology and Immunology, noted, “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.” Galloway added, “Cell-to-cell transmission of HIV is absolutely required for activation of the pathogenic HIV cell-death pathway,” as reported Medical Xpress.
The researchers noted that overall rates of infection are same with free-floating virus infection as well as cell to cell transmission. On the other hand, the death of CD4 T-cells in cell to cell transmission makes a huge difference, explained the investigators.
Dr Warner C. Greene, author of the study and 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.”