Biological parameters of HIV-1 infection in primary intestinal lymphocytes and macrophages

Mucosal surfaces are the portal of entry for most HIV-1 infections and play an important role in disease pathogenesis. To characterize the biological parameters of HIV-1 infection in mucosal cells, we used purified lamina propria lymphocytes and macrophages from normal human small intestine to determine the distribution of the HIV-1 receptor and coreceptors on intestinal mononuclear cells and the permissiveness of these cells to HIV-1 infection. Lamina propria lymphocytes expressed CD4, CCR5, and CXCR4. In contrast, lamina propria macrophages expressed CD4 but not CCR5 or CXCR4. Intestinal lymphocytes supported replication by R5 and X4 isolates of HIV-1, but lamina propria macrophages were permissive to neither. RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta inhibited infection of intestinal lymphocytes by BaL, indicating that R5 infection of the intestinal lymphocytes was mediated by CCR5. Thus, resident lamina propria lymphocytes, not macrophages, are the target mononuclear cell for HIV-1 infection in the intestinal mucosa during early HIV-1 infection.