HUMAN-IMMUNODEFICIENCY-VIRUS AND MYCOBACTERIUM-AVIUM COMPLEX COINFECTION OF MONOCYTOID CELLS RESULTS IN RECIPROCAL ENHANCEMENT OF MULTIPLICATION

Disseminated Mycobacterium avium complex (MAC) infection is an importa nt opportunistic infection in AIDS patients. Because cells of macropha ge lineage are targets for both human immunodeficiency virus (HIV) and MAC, the monocytoid cell line U937 was coinfected with both pathogens . Coinfected cultures had increased HIV replication (more than threefo ld at day 6) and an increased percentage of HIV-infected cells compare d with cultures infected only with HIV. The kinetics of HIV replicatio n were significantly increased in this coinfection system as measured by flow cytometry. When cells were infected concurrently, the rate of intracellular growth of MAC was not significantly affected. However, c ells preinfected with HIV before infection with MAC showed significant enhancement of MAC growth compared with control cells. The kinetics o f cell death were also increased in the coinfection system compared wi th singly infected controls. Thus, coinfection of monocytoid cells wit h HIV and MAC in vitro results in reciprocal enhancement of multiplica tion.