How Lactobacillus and BV associated bacteria affect HIV-1 and HPV susceptibility in the vaginal epithelium

Abstract

Bacterial vaginosis (BV) is a dysbiotic state of the vaginal microbiota which is a common condition that occurs in women of reproductive age. BV is strongly associated with a higher susceptibility for sexual transmitted infections like Human Immunodeficiency Virus type 1 (HIV-1) and Human Papillomavirus (HPV). In a beneficial vaginal microbiome the dominant Lactobacillus spp. maintain a low vaginal pH by secreting lactic acids and prevent HIV-1 and HPV infection s through the production of lectins and other protective compounds. During BV, Lactobacillus spp. are replaced by anaerobic bacteria such as Gardnerella and Prevotella spp., disturbing th is protective environment. Anaerobes produce enzymes that degrade the protective mucus layer and damage the vaginal epithelium, making it more vulnerable for vir al infections In addition, some of these bacteria induce a pro inflammatory response, resulting in damaging of the vaginal epithelium and the recruitment of CD4+ T lymphocytes, the main target cells of HIV-1. This review discusses the molecular mechanisms underlying the increased susceptibility for HIV-1 and HPV infections during BV.