Interplay Between Genital Immunity and Microbiota, Relevant to HIV Risk
Jo-Ann S. Passmore, PhD1,2,3,4
1Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa; 2CAPRISA Centres of Excellence, University of Cape Town, Cape Town, South Africa; 3SA MRC-UCT Gynaecological Cancer Research Centre, University of Cape Town, Cape Town, South Africa; 4National Health Laboratory Service, Cape Town, South Africa
Young people living in sub-Saharan Africa continue to be most severely afflicted by HIV, and understanding factors that influence high HIV risk in this region are critical. Since heterosexual transmission is the predominant mode of new infections, both genital inflammation and alterations in the microbiome are likely to be important underlying causes. This talk will summarize our current understanding by which genital inflammation increases HIV infection risks - by attracting HIV target cells into the vaginal mucosa, or by damaging the mucosal barrier in ways that facilitate HIV penetration, in the context of bacterial vaginosis (BV) and sexually transmitted infections that contribute to increased HIV acquisition risks. Knowledge of the major drivers of HIV risk should directly inform future HIV risk-mitigation interventions in Africa. None of the present approaches to manage STIs or treat BV have demonstrated long-term efficacy and most have focused exclusively on females, including the use of Lactobacilli-containing probiotics and antibiotics that target anaerobic bacteria (such as metronidazole). Whereas most of the probiotics that are used to promote vaginal health do not contain the most common vaginal Lactobacilli spp., antibiotics used to treat BV also kill beneficial anaerobes. Despite our inability to effectively manage BV, in the context of preventing HIV transmission, it is essential that future studies direct us towards novel methods to improve the vaginal health of women as well as mitigate HIV risk in men.