Cytomegalovirus enhances lysis of HIV-infected T lymphoblasts

A T4+ lymphoblastoid cell line (CR-10) persistently infected with the human immunodeficiency virus (HIV) and designated CR-10/NIT was superinfected with cytomegalovirus (CMV) isolated from peripheral blood mononuclear cells of a patient with AIDS. A productive CMV cycle in the CR-10/NIT lymphoblasts was demonstrated by fluorescent antibody staining (IF) using a monoclonal antibody (MAb) to the 150-kDa major capsid protein, by infectivity assays and by electron microscopy (EM). Two-color IF analysis showed that a small percentage of the CR-10/NIT cells were producing both CMV and HIV at any one time. EM studies revealed that all doubly infected cells were lysed whereas most cells infected only with HIV appeared intact. Cell lysis appeared 24 hr after superinfection of the CR-10/NIT cells with CMV and progressed to complete destruction of the cell culture between days 9 and 10. Our results suggest that CMV may convert a mildly cytopathic HIV infection of T lymphoblasts into a highly lytic process.