Figure 1.

Model of HIV mucosal transmission. Vaginal epithelium is composed of a stratified multicellular squamous epithelium, whereas cervical and rectal mucosae have a single-layer cellular lining. During and after crossing the mucosal epithelia, HIV infects LCs, DCs and macrophages, as well as mucosal CD4⁺ T lymphocytes, in the mucosal and sub-epithelial level. Alternatively, DCs (and potentially LCs) capture virus without being infected and transfer it in trans across an infectious synapse to CD4⁺ T cells. The ‘founder’ infected cells amplify virus and migrate to the peripheral lymph nodes where they transfer virus to bystander cells. Viral load increases rapidly when the virus reaches the GALT.