Effect of Glycyrrhizin, Cyclosporin A, and Tumor Necrosis Factor Alpha on Infection of U-937 and MRC-5 Cells by Human Cytomegalovirus

Reactivation of latent or persistent human cytomegalovirus (HCMV) infection of monocytes or macrophages occurs under immunosuppressive conditions. We investigated the effect of glycyrrhizin (GL), cyclosporin A (CsA), and tumor necrosis factor-alpha (TNF-alpha) on the viral DNA synthesis and antigen expression of HCMV in U-937 and MRC-5 cells. Although GL inhibited the viral antigen expression of HCMV in human monocytic cell line U-937 and human embryonic lung cell line MRC-5 in the study, as determined by flow cytometry and immunofluorescence assay, immediate early HCMV DNA was detected by the polymerase chain reaction. CsA or TNF had no inhibitory effect on HCMV in U-937 or MRC-5 cells. The HCMV infection model with U-937 or MRC-5 cells is of use for clarifying not only the mechanism of persistent infection but also the anti-HCMV effect of chemical agents.