Epidermal Langerhans cells and HIV-1 infection

Originating from the bone marrow, Langerhans cells migrate into the peripheral epithelia (skin, mucous membranes) and play a key role in the immune surveillance system against foreign antigens. They act as antigen-presenting cells through a specific cooperation with CD4+ lymphocytes after migration to the proximal lymph nodes. As HIV-1-permissive cells, Langerhans cells in genital or rectal mucosa may be the first infected cell type and may be the vectors of infection for CD4-positive T cells. It has been clearly demonstrated that Langerhans cells may be infected in HIV-1 sero-positive patients. Recently in vitro experimental infection of Langerhans cells was achieved using a co-culture assay with HIV-1-infected cells. Investigation into the exact role of Langerhans cells in the course of HIV-1 infection will contribute greatly to our understanding of AIDS pathogenesis.