Normally functioning epithelial cells that line the prostate and cervix provide protection against HIV transmission, according to new data from the Centers for Disease Control and Prevention (CDC). However, when altered by infection with other sexually transmitted diseases, that protection is lost and the cells actually may facilitate HIV transmission.
The findings, presented today at the 12th World AIDS Conference by CDC researcher Charlene Dezzutti, Ph.D., are the first to distinguish between the role primary cells (normally functioning) and immortalized cells (cells in which the genetic makeup has been altered either by the presence of disease or genetic abnormalities) play in HIV transmission.
These findings lead us to a clearer understanding of factors influencing the sexual transmission of HIV," said Dezzutti, "This is the first study to demonstrate that normally functioning epithelial cells are incapable of transmitting HIV. But STDs and other factors which damage these cells can play a major role in the sexual spread of this epidemic."
Epithelial cells make up the mucous membranes that line the prostate, cervix, and other body cavities. Previous research suggested that transmission of HIV through these cells could occur. But Dezzutti's study suggests that this may only be possible if either the cells or the bond between the cells has been damaged.
The study compared primary epithelial cells from the prostate to immortalized epithelial cells that had been infected by the human papilloma virus (HPV) from the cervix to determine the ability of HIV to pass through both types of cells.
Findings indicate that primary prostate cells did not transmit HIV, while the immortalized cells were capable of transmission. The normally functioning cells formed a tight bond between cells that would not allow HIV to pass through, while the immortalized cells failed to develop a tight bond and did allow passage of the virus.
Researchers believe that in addition to HPV, other STDs such as gonorrhea and syphilis can also prevent cells from developing tight bonds and therefore facilitate HIV transmission. "This study adds to mounting evidence that STDs greatly increase the risk of acquiring HIV," said Helene Gayle, M.D., M.P.H., Director of CDC's National Center for HIV, STD, and TB Prevention. "HIV prevention strategies, particularly for women, must include efforts to prevent and treat other STDs."