INFECTION OF GASTROINTESTINAL-TRACT MACROPHAGES BY HIV-1

As the largest lymphoid organ and the largest reservoir of macrophages in the body, the gastrointestinal tract mucosa is probably the larges t organ reservoir of macrophages infected with HIV-1, To elucidate the biology of HIV-1 infection of intestinal macrophages, we isolated lam ina propria macrophages from normal human jejunum by neutral protease digestion, purified the cells by counterflow centrifugal elutriation, and then infected the cells with HIV-1, The lamina propria macrophages were permissive to macrophage-tropic isolates of HIV-1 and substantia lly less permissive to lymphocyte-tropic isolates, Compared with blood monocytes, mucosal macrophages produced 2-3 logs less p24 antigen at peak infection, The reduced level of infection was not due to impaired macrophage viability, reduced CDP expression, or the isolation proced ure. These results confirm that macrophages isolated from the gastroin testinal tract mucosa can support HIV-1 production, albeit at a lower level than blood monocytes. The reduced level of virus production may reflect the unique biology of intestinal lamina propria macrophages.