Photoaffinity labeling demonstrates binding between Ia molecules and nominal antigen on antigen-presenting cells.
- 1 August 1986
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 83 (15), 5634-5638
- https://doi.org/10.1073/pnas.83.15.5634
Abstract
We have used radioiodinated photoreactive bovine insulin as antigen to examine the molecular nature of immunogenic complexes that form on antigen-presenting cells. The probe was allowed to bind to either insulin-presenting B-hybridoma cells, lipopolysaccharide-stimulated blasts, or bovine insulin-specific helper-T-hybridoma cells in the dark. Samples were then exposed to light to induce crosslinkage, solubilized, and analyzed by gel electrophoresis. Two protein bands at about 36 kDa and 27 kDa were specifically labeled on antigen-presenting cells but not on helper T cells. Treatment of these bands with dithiothreitol or endo-.beta.-N-acetylglucosaminidase F showed that each is composed of a single glycoprotein. These proteins are immunoprecipitable with haplotype-specific but not control anti-Ia antibodies. This identifies the labeled bands as the .alpha. and .beta. subunits of class II major histocompatibility antigens. We conclude that a molecular complex may form between Ia and antigen on antigen-presenting cells and that formation of this complex does not require the presence of a helper-T-cell antigen receptor.This publication has 39 references indexed in Scilit:
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