BIDIRECTIONAL TRANSMISSION OF INFECTIOUS CYTOMEGALOVIRUS BETWEEN MONOCYTES AND VASCULAR ENDOTHELIAL-CELLS - AN IN-VITRO MODEL

Cytomegalovirus (CMV) infects multiple tissues and organs; however, me chanisms of dissemination remain elusive. Although hematogenous spread has been implicated, in vitro studies have generally indicated that p eripheral blood mononuclear cells (PBMC) do not support the complete v iral reproductive cycle. Since CMV infects endothelial cells (EC), the hypothesis that PBMC can be productively infected by contact with CMV -infected EC was tested by coculturing PBMC with CMV-infected endothel ial monolayers. Dual immunohistochemical staining for mononuclear cell markers and CMV-specific antigens demonstrated infection of up to 30% of monocytes adhering to EC. To determine if infected monocytes could transmit infectious virus, they were separated from EC, replated in c ulture wells, and then overlaid with fresh EC, The subsequent appearan ce of CMV-positive cytopathic foci within the overlaid monolayers indi cated that these monocytes were capable of transmitting infectious vir us. Thus, these results support an interactive role for the endotheliu m and circulating monocytes in the dissemination of this clinically pr oblematic virus.