Primary amines enhance the antiviral activity of interferon against a membrane virus: role of intracellular pH.
Inhibition of vesicular stomatitis virus (VSV) replication in LB cells by interferon (IFN) resembles the action of IFN on some retroviruses, in that the incorporation of glycoprotein into virions is defective. Primary amines added between 1 and 2 h post-infection significantly enhanced (five- to 1000-fold) the antiviral activity of IFN against VSV, but no enhancement of the antiviral activity of IFN against encephalomyocarditis virus, a virus with no membrane component, by primary amines was seen. SDS-PAGE and immunofluorescence analysis of viral proteins, and Nycodenz gradient fractionation, suggested that both IFN and primary amines inhibited the transport of VSV glycoprotein (G) to the plasma membrane; instead, G accumulated in the trans-Golgi network (TGN). Using sensitive intracellular pH (pHi) indicators, we found that IFN treatment significantly raised the pHi. A further increase in pHi was seen with a combination of IFN and primary amines; the increase in pHi correlated with an enhancement of the antiviral activity of IFN by primary amines. Amiloride inhibited the IFN-induced increase in pHi and a concomitant increase in the concentration of Na+ ions; this observation suggested that IFN induced cytoplasmic alkalinization by activating an Na+/H+ antiporter system. These results indicated that the IFN-induced increase in pHi may be responsible for the accumulation of G in the TGN, thereby producing G-deficient virus particles with reduced infectivity.
Maheshwari
R K
RK
Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799.
Sidhu
G S
GS
Bhartiya
D
D
Friedman
R M
RM
D000218:Adamantane / Q000031:analogs & derivatives / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000588:Amines / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D004306:Dose-Response Relationship, Immunologic; D004686:Encephalomyocarditis virus / Q000187:drug effects / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006863:Hydrogen-Ion Concentration; D007370:Interferon Type I / Q000276:immunology*; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000276:immunology*; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins / Q000276:immunology; D012964:Sodium / Q000378:metabolism; D014709:Vero Cells; D014721:Vesicular stomatitis Indiana virus / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000276:immunology / Q000378:metabolism*
D000588:Amines; C028391:G protein, vesicular stomatitis virus; D007370:Interferon Type I; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins; C016358:2,4-diamino-5-adamantyl-6-methylpyrimidine; D000584:Amiloride; D012964:Sodium; D000218:Adamantane