NOVEL HETEROGENEITY OF THE LEUKOCYTE COMMON ANTIGEN (CD45) - DISULFIDE-BOUND HETERODIMERS BETWEEN CD45 AND AN 80 KDA POLYPEPTIDE

The leukocyte common antigen, CD45, is one of the major glycoproteins on cells of hemopoietic origin showing considerable, heterogeneity in both structure and expression. Biochemical heterogeneity has been attr ibuted to differences in the primary sequence and glycosylation. In th is paper we report an additional basis for generation of heterogeneity by revealing that CD45 can form disulfide-bound heterodimers with an 80 kDa polypeptide. Since a respectable fraction of the CD45 molecules is involved in heterodimer formation, it is suggested that the 80 kDa polypeptide could be involved in the regulation of CD45 function.