NMSO-3

We report the synthesis of a novel alkyl polysulfated sialic acid derivative denoted as NMSO3. NMSO3 exhibited potent inhibition against both laboratory and clinical human immunodeficiency virus type 1 (HIV-1). The anti-viral activity of this compound (1 uM) was compared to dextran sulfate (3 uM), and was found to be more potent against HIV-1IIIb than AZT (10 uM). The anti-coagulation time was more than 15-fold shorter than that of dextran sulfate. An in vivo anti-viral study of NMSO3 in NOD-SCID-PBL mice HIV model showed complete protection of the animals from virus challenge at the concentration of 10 mg/kg. This suggests that NMSO3 can be effective in the treatment of HIV-infected individuals.

We have previously reported that a pseudotype virus generated by reconstitution of hepatitis C virus (HCV) chimeric envelope glycoprotein E1-G or E2-G on the surface of a temperature-sensitive mutant of vesicular stomatitis virus (VSVts045) interacts independently with mammalian cells to initiate infection. Here, we examined whether coexpression of both of the envelope glycoproteins on pseudotype particles would augment virus infectivity and/or alter the functional properties of the individual subunits. Stable transfectants of baby hamster kidney (BHK) epithelial cells expressing either one or both of the chimeric envelope glycoproteins of HCV on the cell surface were generated. The infectious titer of the VSV pseudotype, derived from a stable cell line incorporating both of the chimeric glycoproteins of HCV, was ∼4- to 5-fold higher than that of a pseudotype bearing E1-G alone or ∼25- to 30-fold higher than that of E2-G alone when assayed with a number of mammalian cell lines. Further studies suggested that that the E1-G/E2-G or E2-G pseudotype was more sensitive to the inhibitory effect of heparin than the E1-G pseudotype. Treatment of the E1-G/E2-G pseudotype with a negatively charged sulfated sialyl lipid (NMSO3) displayed a ∼4-fold-higher sensitivity to neutralization than pseudotypes with either of the two individual glycoproteins. In contrast, VSVts045, used as a backbone for the generation of pseudotypes, displayed at least 20-fold-higher sensitivity to NMSO3-mediated inhibition of virus plaque formation. The effect of low-density lipoprotein on the E1-G pseudotype was greater than that apparent for the E1-G/E2-G pseudotype. The treatment of cells with monoclonal antibodies to CD81 displayed an inhibitory effect upon the pseudotype with E1-G/E2-G or with E2-G alone. Taken together, our results indicate that the HCV E1 and E2 glycoproteins have separable functional properties and that the presence of these two envelope glycoproteins on VSV/HCV pseudotype particles increases infectious titer.