According to a new study, HIV-resistant sex workers in Africa have a weak inflammatory response in their vaginas. The researchers, led by Dr. Michel Roger of the University of Montreal Hospital Centre and the university's Department of Microbiology and Immunology, were surprised by this finding, as they expected the opposite, due to the women's high exposure to the virus.
"In this part of the world, women represent over 60% of HIV cases, and this proportion continues to increase. Studying women who are naturally resistant to the virus enables researchers to identify interesting information in terms of developing vaccinations or microbid gels that could prevent transmission of HIV."
The word microbid refers to something that is able to destroy microbes.
In order to get a clearer picture of the immune and molecular mechanisms involved in the transmission of HIV, Roger has been working with women from Zimbabwe and Benin for the past decade and a half. The researchers targeted Benin and Zimbabwe, due to the high incidence of HIV-infected women and that some of them were naturally HIV-resistant.
The team discovered that the immune system cells in the vaginas of HIV-infected women generated more inflammatory molecules (cytokines and chemokines) than the same cells in HIV-resistant women.
Cytokines and chemokines help to activate and recruit "lymphocyte T-cells" that usually attack and destroy viruses. However, HIV uses the T-cell to attack the body. Roger said: "Fewer T-cells means fewer target cells available for the virus to use."
Results from the study showed that the immune response was extremely different in the women's blood than in their vaginal mucous membrane. According to the findings, it would be more effective to produce vaccinations that would obstruct the virus at entry point of the body, instead of attempting to fight it after the virus is already established within the body's system.
"AIDS vaccination research has entirely focused on the blood stream and this approach has been a failure. Our research shows that the immune response is different at the site of the infection, and that we should turn to the entry points in order to find a means for blocking the virus."
This type of vaccination would immunize all mucus membranes in the body and could be administered via the nose.
The researchers will continue their research in order to get a clearer picture of the molecular mechanisms involved in the vaginal immune response. According to scientists, genetic factors may play a role as they have found that sisters living in similar circumstances have the same HIV-resistant profile.
Written by: Grace Rattue