β 2 -Microglobulin and Its Relationship to the Immune System

Abstract

β 2-Microglobulin has been isolated from several species, but only bovine β2-microglobulin, previously known as lactollin, has been crystallized. An improved method for its isolation from colostrum is described. The bovine homologue exhibits a concentration-dependent aggregation behavior. β2-Microglobulin is related to both immune and histocompatibility antigen systems. It exhibits homology with the constant domains of the immunoglobulin-G light and heavy chains and is an integral part of histocompatibility antigens bound to cell surface. β2-Microglobulin also occurs in the free state in various body fluids including milk and colostrum. The possible relationship of elevated free β2-microglobulin to pathological conditions is suggested for future research. © 1982, American Dairy Science Association. All rights reserved.