Adsorption of interferon to homologous and heterologous cells. Brief report

Lanthanide ion enhancement of interferon binding to cells

Pretreatment of purified [125I]-labeled human and mouse beta interferons (IFN) with lanthanum chloride (LaCl3) enhanced 20-30 fold the binding of the [125I]-IFNs to human A549 and mouse L cells at 0 degree C and also enhanced antiviral activity in homologous cells. Although lanthanides enhanced cross-species binding of both human and mouse [125I]-IFNs, there was no increase in cross-species antiviral activity. Unlabeled IFN not treated with LaCl3 did not compete with [125I]-IFN treated with LaCl3 for cellular receptors. However, unlabeled IFN treated with LaCl3 did compete with LaCl3-treated [125I]-IFN. These results suggest that lanthanide treated IFNs do not bind to the same receptors as native IFNs.

Effect of interferon on cyclic adenosine monophosphate levels in cells

Treatment of murine and human cells with homologous interferon (IFN) resulted in an elevation of the cellular cyclic adenosine monophosphate (cAMP) levels in a time- and dose-dependent manner. A similar elevation of cAMP levels could be produced by treatment of cells with isoproterenol, prostaglandin or methylxanthine. However, these agents did not produce an antiviral state. Pretreatment with an inhibitor of adenyl cyclase, N-ethylmaleimide, prevented the effect of IFN on cAMP levels, but did not influence tis antiviral activity.

Interferon induces an antiviral state in ganglioside-deficient transformed mouse fibroblasts

The antiviral activity of mouse fibroblast interferon against vesicular stomatitis virus was investigated in L-929 mouse fibroblasts and the ganglioside-deficient L-929 mutant cells (ATCC clone NCTC 2071). Although it has been widely reported that gangliosides serve as primary receptors for interferon at the cellular membrane, only a small difference in interferon sensitivity was observed between the wild-type L-929 and the ganglioside-deficient NCTC 2071 cells. It was not possible, however, to overcome this difference by administration of exogenous gangliosides.