And yes, it is very likely that I will manage to work this into a conversation with someone about prevention.
Aidsmap | Cellular infection study partially explains lower HIV infection rates through oral sex
Aidsmap | Cellular infection study partially explains lower HIV infection rates through oral sex
A study in which slices of human mucosal tissue were infected with HIV has partially explained why HIV is caught so much more easily through anal sex than through oral sex. The study, in which tissue samples from the tonsils and the rectum were infected with two different kinds of HIV, found that rectal CD4 cells express five times as much of the CCR5 receptor molecule on their surface as tonsil cells. This is the co-receptor for R5 or M-tropic virus, the variety of HIV that is usually transmitted. Rectal CD4 cells, once infected, also produced more of this virus than tonsil cells.
The study also found that in response to infection with the other kind of HIV, X4 or T-tropic virus, tonsil cells, but not rectal ones, secreted chemicals called chemokines that blocked further access to the CCR5 receptors.
However, while showing why CD4 cells in the tonsils are so much less susceptible to R5 infection than rectal ones, it does not show why these cells – most of which also carry the CXCR4 receptor – are so much less likely to be infected with X4 virus in vivo than in the laboratory. The researchers say that another so far undetected defence against X4 virus must exist.
The research team was led by scientists from the US National Institute of Child Health and Human Development in Bethesda, Maryland, and also included prominent microbicide researchers Ian McGowan from UCLA and Robin Shattock from St George’s Hospital, London.
