Copyright © 1991, American Society for Microbiology Human Cytomegalovirus Productively Infects Primary Differentiated Macrophagest

Monocytes are one of the predominant cell types in the peripheral blood that are infected by human cytomegalovirus (HCMV). Although virus can be detected in these cells in vivo, HCMV replication in cultured monocytes has been unsuccessful. In this study, we demonstrate efficient HCMV replication in cultured monocytes. HCMV permissiveness in these cells was dependent on nonadherent cell-induced stimulation of the monocyte, with subsequent morphological differentiation into macrophages. Approximately 40 % of the cells infected by virus were detected by immunofluorescent staining with both immediate-early and late antibodies. In addition, viral plaque assays demonstrated signfficant productive infection of macrophages. These observations are consistent with the suggestion that the monocyte/macrophage serves as a source of viral amplification and dissemination. Human cytomegalovirus (HCMV) infection of immuno-compromised patients often results in acute disease (10). The virus may also contribute to the immune dysfunction ob-served in these individuals by directly infecting lymphoid cells (3, 19). HCMV immunosuppression is exemplified by a depressed lymphocyte response to T-cell mitogens (3, 13, 27