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.

As described above, SPGG is a highly sulfated agent that can theoretically bind to several HS-binding proteins. One of these proteins is glycoprotein gB of HCMV, which is a known heparin-binding protein [69, 70] . In fact, the design of this work, was based on the expectation that SPGG would bind to one of the viral surface glycoproteins. To test this expectation, we studied whether SPGG binds to gB using dot-blot hybridization and cell-ELISA assay. Figure 6 (panels A,B) shows the results of the dot-blot in the presence and absence of SPGG. As the concentration of SPGG increased to 100 µM, the gB signal reduced 30.5 ± 10% of the untreated control. Although a reduction in signal intensity at lower concentrations (<10 µM) was noticeable, the inhibition was not as robust as observed with IC 50 profiles of viral entry or expression of genes (Figures 3 and 4 above) . To further test whether SPGG engages viral entry glycoprotein gB, we studied Chinese Hamster Ovary cells (CHO-K1) that over-express HCMV gB on cell surface. Dot-blot hybridization and cell-ELISA of CHO-K1 cells in the presence of 100 µM SPGG also led to reduction in gB signal intensity of 34.6 ± 20% in comparison to mock-treated controls ( Figure 6C ).