Replication of murine cytomegalovirus in lung macrophages: effect of phagocytosis of bacteria.

Murine cytomegalovirus was found to replicate in lung and peritoneal macrophages of both CF-1 and BALB/c mice in vitro. Cytopathic changes typical of cytomegalovirus infection, including intranuclear inclusions, developed within the infected cells and eventually resulted in death of infected macrophages. Viral antigens were demonstrable by indirect immunofluorescence microscopy, and morphologically typical herpesvirus particles were observed in both nuclei and cytoplasm of murine cytomegalovirus-infected macrophages. Within 24 h after infection, at which time there was expression of viral antigens but no marcophage death, murine cytomegalovirus-infected macrophages demonstrated marked inhibition of phagocytosis of Staphylococcus aureus. Direct inhibition of macrophage function by cytomegalovirus infection in vivo could impair pulmonary defenses and may account in part for the frequent association of cytomegalovirus infection with other infectious agents.