The mechanisms determining how virus is passed through the genital epithelium to underlying immune cells are poorly understood. Consequently, there is a need for a model to study the events of HIV-1 genital infection as well as evaluation of microbicides to inhibit HIV-1 transmission. Studies in nonhuman primates have provided insight into the role of the mucosa during SIV infection; however, use of a different retrovirus and the ensuing disease course, together with ethical issues and the high cost of animal husbandry, necessitate development of in vitro assays which better duplicate the human genital tract environment. Use of small animal models (mice and rabbits) for microbicide testing presents similar problems given the inability to infect these animals with HIV-1. The studies proposed in this application utilize an in vitro model that uses both primary cervical epithelial and stromal immune cells. Microbicide toxicity will be evaluated with primary epithelial cells in a transwell system and cervical epithelial sheets clamped into diffusion chambers. The ability of a microbicide to inhibit HIV-1 infection and replication in cultured mucosal immune cells will also be examined. Finally, the cervical explant model will be used to determine the ability of a microbicide to inhibit dissemination of HIV-1 to local cells during immune activation or degradation of the epithelial barrier by mucosal pathogens (T. pallidum and T. vaginalis). The proposed experiments will provide valuable insight into microbicide development and may obviate the need for small animal testing.
