Inhibition of Human Cytomegalovirus Entry into Host Cells through A Pleiotropic Small Molecule

Elste, James; Kaltenbach, Dominik; Patel, Vraj R.; Nguyen, Max T.; Sharthiya, Harsh; Tandon, Ritesh; Mehta, Satish K.; Volin, Michael V.; Fornaro, Michele; Tiwari, Vaibhav; Desai, Umesh R.

The plaque reduction assay was performed on HFF-1 cells using SPGG-treated or PBS mocktreated reporter virus. Initial experiments were performed to deduce the optimal concentration of MOI and period of infection with wild-type virus to detect foci to aid study of cell-to-cell spread. Treatment of HFF-1 with mock-treated HCMV strain RC256 for seven-days followed by x-gal staining and quantification of the blue-colored infected foci under 10× magnification led to highly reproducible measurement of viral spread. When 100 µM SPGG was used to pre-treat the virions, significantly fewer foci were observed after 7 days. Although the punctae observed in the assays may be aggregates of multiple viral particles, counting the number of viral foci showed a dramatic decrease in comparison to the mock-treated HCMV ( Figure 5 ). This is especially important because Our study is first to report a unique heparin mimetic, which has been previously been reported as a broad spectrum antimicrobial activity, as an inhibitor of HCMV. Earlier, we have demonstrated that SPGG inhibits HSV [50, 51] and Chlamydia infection [66] . Since HSV and Chlamydia are known to exploit heparan sulfate during early stages of host pathogen interactions [66, 67] , SPGG's lowering of HCMV early gene expression is not too surprising considering that the viral entry is blocked in the first place. A more important point of this result is the possibility that SPGG could be utilizing multiple mechanisms for its antiviral effects.