Structural and functional properties of membrane and secreted IgD

More than 35 years ago, study of an unknown immunoglobulin (Ig) in the seru m from a myeloma patient led to the discovery of IgD. Subsequently, the fin ding that it also exists as a membrane-bound Ig stimulated a large number o f studies during the 70s. Then, the interest on IgD shrank, largely because of the lack of known function of secretory IgD (secIgD) and of a stagnatin g knowledge of the functions of surface IgD. In the recent years, very sign ificant advances followed the tremendous accumulation of data on the physio logy of the B cell receptor, of which IgD is the major component, on the ro le of secIgD in normal and diseased individuals. This review, which is focu sed on human IgD but integrates data in the mouse and other species when ne eded, summarizes present data on the structure, synthesis and functions of both membrane and secIgD, IgD receptors and the involvement of IgD in vario us diseases, especially the hyperIgD syndrome. (C) 2001 Elsevier Science Lt d. All rights reserved.