Replication of cytomegalovirus in human thymic epithelial cells

Cytomegalovirus (CMV) has often been cited as a cause of immune suppression in children, yet little is known of the mechanisms through which this agent might affect immune function. We have succeeded in using CMV to productively infect cultured human fetal and infantile thymic epithelial (TE) cells. Morphological changes were apparent by 2-4 days after viral inoculation. CMV-related early antigen (EA) and late antigen (LA) were detected by immunofluorescence after 8 days, and progeny infectious CMV was recovered from culture media after 12-17 days. TE cells that reacted with monoclonal antibodies specific for keratin and for GQ ganglioside were predominant throughout the culture period. In contrast, infection by CMV resulted in a significant decrease in numbers of cells reactive with monoclonal antibodies specific for mesoderm-derived components. Inoculation of TE cells with CMV also caused a diminution in levels of detectable interleukin-1 (IL-1)-related antigen by 17 days after infection.