The HIV epidemic is still increasing globally and several large vaccine trials have failed. The research field has clearly underscored the enormous intra-individual variations that exist in HIV/AIDS susceptibility. Even at one anatomical site, such as the female genital tract, different prerequisites exist including thickness of mucus layers, type of epithelia, and expression of HIV receptors and localization of primary target cells. Differently composed repertoires of innate immune defences are also present at each site. Genetic, hormonal and inflammatory conditions further increase the individual variations complicating all types of prophylactic trials. Our research group studies early events of HIV transmission at genital mucosal sites and the corresponding innate and adaptive mucosal immunity.
In large ongoing prospective cohort studies of men and woman in Nairobi, Kenya, we collect mucosal samples of highly exposed seronegative individuals. The study groups include commercial sex workers and subject living with an HIV infected partner. Genital mucosal samples are analysed to find correlates of protective immunity in comparison to relevant control groups. The innate and the adaptive immune responses are evaluated by functional assays and tissue biopsies are analysed by confocal microscopy for immune markers. Our scientific collaborators in Kenya, Canada and US complement the work with studies on cellular immunity and genetic factors on the same material. This collaborative effort will hopefully increase our understanding of correlates of protective immunity against HIV infection.