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Molecular components of the B cell antigen receptor complex of class IgD differ partly from those of IgM.
Author(s) -
Wienands J.,
Hombach J.,
Radbruch A.,
Riesterer C.,
Reth M.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb08130.x
Subject(s) - immunoglobulin d , biology , antigen , microbiology and biotechnology , receptor , transmembrane protein , cell surface receptor , b cell receptor , t cell receptor , antibody , transmembrane domain , b cell , immunology , t cell , biochemistry , immune system
Two classes of immunoglobulin, IgM and IgD, are present as antigen receptors on the surface of mature B lymphocytes. We show here that IgD molecules are noncovalently associated in the B cell membrane with a heterodimer consisting of two proteins of 35 kd (IgD‐alpha) and 39 kd (Ig‐beta), respectively. The two novel proteins are not found in the IgD‐expressing myeloma J558L delta m, which fails to bring IgD antigen receptor onto the cell surface. In a surface IgD positive variant line of this myeloma, however, membrane‐bound IgD molecules are associated with the heterodimer, suggesting that the formation of an antigen receptor complex is required for surface IgD expression. We further demonstrate that the IgD‐associated heterodimer differs partly from that of the IgM antigen receptor and that its binding to the heavy chain only requires the presence of the last constant domain and the transmembrane part of the delta m chain.