Inhibiting Rotavirus Infection by Membrane-Impermeant Thiol/Disulfide Exchange Blockers and Antibodies against Protein Disulfide Isomerase

Objectives: Determining the effect of membrane-impermeant thiol/disulfide exchange inhibitors on rhesus rotavirus infectivity in MA104 cells and investigating protein disulfide isomerase (PDI) as a potential target for these inhibitors. Methods: Cells were treated with DTNB [5,5-dithio-bis-(2-nitrobenzoic acid)], bacitracin or anti-PDI antibodies and then infected with virus. Triple-layered particles (TLPs) were also pretreated with inhibitors before inoculation. The effects of these inhibitors on alpha-sarcin co-entry, virus binding to cells and PDI-TLP interaction were also examined. FACS analysis, cell-surface protein biotin-labeling, lipid-raft isolation and ELISA were performed to determine cell-surface PDI expression. Results: Infectivity became reduced by 50% when cells or TLPs were treated with 1 or 6 m M DTNB, respectively; infectivity became reduced by 50% by 20 m M bacitracin treatment of cells whereas TLPs were insensitive to bacitracin treatment; anti-PDI antibodies decreased viral infectivity by about 45%. The presence of DTNB (2.5 m M) or bacitracin (20 mM) was unable to prevent virus binding to cells and rotavirus-induced alpha-sarcin co-entry. Conclusions: It was concluded that thiol/disulfide exchange was involved in rotavirus entry process and that cell-surface PDI was at least a potential target for DTNB and bacitracin-induced infectivity inhibition. Copyright (C) 2012 S. Karger AG, Basel