The B-cell antigen receptor of the five immunoglobulin classes

Abstract

Several proteins associate with surface IgM to form the antigen receptor. We show that just two, the α and β associated chains, are sufficient to reconstitute an IgM surface receptor in fibroblasts. Contrary to expectation, α common a chain associ-ates with all five immunoglobulin classes. We pro-pose that B-cell antigen receptors consist of a common α/β heterodimer associated with each immunoglobulin class. But the classes differ both in the glycosylation of their associated α chain and in their dependence on α/β for surface transport.