Human Epidermal Langerhans Cells Efficiently Present HIV-1 Antigens to Specific T Cell Lines

Dendritic cells (DC) play a dominant role in T cell priming both in vitro and in vivo. We have shown that peripheral blood (PB) DC are the most efficient APC for presentation of the HIV-1 envelope glycoprotein gpl20 to specific CD4+ T cells and are required for in vitro generation of gp120-specific T cell lines from unprimed individuals1. Epidermal DC, i.e. Langerhans cells (LC), are the critical APC for the induction of T cell immunity against Ag that are present in or penetrate through squamous epithelia2. LC obtained from HIV-infected subjects contain HIV-1 proviral DNA and RNA3, and can release HIV virions, thus indicating that LC are productively infected by the virus in vivo.