A demonstration of human beta-2-microglobulin specific association with the surface of teleostean cells

Abstract

Purified human Beta-2 microglobulin (ß2m) and a human 2m fluorochrome conjugate were used in exchange reactions to demonstrate that ß2m associates with a teleostean cell surface protein. 2m exchange among brown bullhead, channel catfish, fathead minnow, and rainbow trout cell lines was detected by using either radioimmunoassay or flow cytometry. Evidence that 2m binds specifically with the surface of teleostean cells and possibly associates with an expressed class I MHC homologue is provided. Moreover, following exchange on brown bullhead cells, a coprecipitated protein of 45 kDa was observed following subsequent immunoprecipitation with the human ß2m specific antibody B1.1G6. Given that β2m is a peripheral protein which has been shown to exchange with MHC expressing cells from different species, co-precipitation results suggest that the 45 kDa protein may represent a class I MHC homologue. © 1995 Elsevier Science Ltd.