HUMAN IMMUNODEFICIENCY VIRUS ON RECOMBINANT COLONY-STIMULATING FACTOR I-TREATED MONOCYTES

Infection with the human immunodeficiency virus (HIV) (1-3) often results in clinically apparent disease only after intervals of months to years. During this latent or subclinical phase of infection, HIV continues to replicate at low levels despite an often vigorous but apparently ineffective host immune response (4) . Mechanisms that contribute to this persistent, low-level infection, as well as the cellular reservoirs for HIV during this latent period, are not fully understood . Several lines of evidence now document cells of the monocyte/macrophage lineage as major targets for persistent HIV in vivo (5-12) . In this respect, HIV is similar to several ruminant lentiviruses that show strong tropism for macrophages during both viral latency and active replication (13-15) . If macrophages also serve as a viral reservoir during HIV infection, then analysis of these infected cells may explain mechanisms of viral persistence, dissemination, and ultimately clinical disease . In this report, we describe an in vitro system that allows replication of HIV in blood-derived monocyte/macrophages from normal donors . Purified monocytes were cultured for intervals > 3 mo in medium supplemented with human rCSF-1 (16, 17) . These cultures provided susceptible target cells for HIV infection . Cocultivation of PBMC from patients with AIDS or AIDS-related complex (ARC)' and rCSF-1-treated monocytes from normal donors resulted in isolation of progeny HIV virions in the majority of patients tested