THE ALPHA-GLUCOSIDASE INHIBITOR N-BUTYLDEOXYNOJIRIMYCIN INHIBITS HUMAN-IMMUNODEFICIENCY-VIRUS ENTRY AT THE LEVEL OF POST-CD4-BINDING

The ar-glucosidase inhibitor N-butyldeoxynojirimycin (NB-DNJ) is a potent inhibitor of human immunodeficiency virus (HN) replication and syncytium formation in vitro. However, the exact mechanism of action of NB-DNJ remains to be determined. In this study we have examined the impairment of HIV infectivity mediated by NB-DNJ. By two independent HN entry assays [PCR-based HIV entry assay and entry of Cocal(HIV) pseudotypes], the reduction in infectivity was found to be due to an impairment of viral entry. No effect of NB-DNJ treatment was seen on the kinetics of the interaction between gp120 and CD4 (surface plasmon resonance; BIAcore) or on the binding of virus particles to H9 cells (using radiolabeled virions). We therefore conclude that a major mechanism of action of NB-DNJ as an inhibitor of HIV replication is the impairment of viral entry at the level of post-CD4 binding, due to an effect on viral envelope components.