Interferon receptors. Cross-linking of human leukocyte interferon alpha-2 to its receptor on human cells.

Abstract

Experiments were carried out to identify the receptor for human interferon (HuIFN)-a on human cells.Binding of '2aI-labeled HuIFN-aa was tested with four human cell lines, Daudi, WISH, and two human osteogenic sarcoma cell lines, SAOS-2 and U20S.The latter cell line is rather insensitive to HuIFN-u and HuIFN-p.Daudi, WISH, and SAOS-2 cells showed specific binding of 'asI-HuIFN-az which was displaced by unlabeled HuIFN-aa, HuIFN-a(Le), and HuIFN-/3 but not by HuIF'N-y.The IFN-insensitive U20S cells showed no detectable displaceable binding of 'Z61-IFN-aa, indicating either a lack of IFN receptors or a much lower aflnity for IFN.Two croos-linking reagents (dithiobis(succinimidy1)propionate) and disuccinimidyl suberate) were used to test whether the cell-bound IFN could be cross-linked to its receptor.The cell-bound IFN-aa was cross-linked and yielded a complex with an apparent M, -160,000.Experiments indicate that this cross-linked complex represents IFN-UZ bound to its receptor or a component of it: (i) this complex formation was not detected on IFN-insensitive U20S cells; (ii) the cross-linked complex could be immunoprecipitated with anti-HuIFN-a antibodies but not with anti-HuIFN-/3 antibodies; (iii) the complex formation with "'11-IFNa 2 was displaced by unlabeled HuIFN-a~, HuIFN-a(Le), and HuIFN-/3 but not by H u m -y and very poorly by mouse IFN-a,P; the latter result suggests that the species specificity of IF'N may reside at the receptor level:(iv) the complex formation was abolished by pretreatment of cells with trypsin but not with neuraminidase, indicating that the receptor is at least in part protein.The complex obtained from neuraminidase-treated cells migrated slightly faster in polyacrylamide gels, suggesting that this IFN-binding component may be a glycoprotein."