Specificity of the murine IgD receptor on T cells is for N-linked glycans on IgD molecules.
IgD receptors on murine T cells have been reported in this issue [Tamma, S. M. L., Amin, A. R., Finkelman, F. D., Chen, Y.-W., Thorbecke, G. J. & Coico, R. F. (1991) Proc. Natl. Acad. Sci. USA 88, 9233-9237] to bind either the first or third constant region of the heavy-chain of IgD molecules--findings that could not be satisfactorily explained by IgD amino acid sequences. We now find that boiled IgD molecules or low-Mr fragments from protease-digested IgD still inhibit binding of IgD-coated erythrocytes to IgD receptors. This inhibitory activity can be absorbed with the murine IgD-binding lectin from Griffonia simplicifolia 1 (GS-1) immobilized on Sepharose. N-linked glycans, obtained from N-glycanase-treated IgD and purified by binding to GS-1-Sepharose, also inhibit rosette formation of T-helper cells bearing receptors for IgD with IgD- or mutant IgD-coated erythrocytes. Deglycosylated IgD, produced by treatment with N-glycanase, no longer binds to the lectin and fails to inhibit IgD rosetting. Binding of intact IgD to T cells is also competitively inhibited by N-acetylgalactosamine, galactose, N-acetylglucosamine, and neoglycoproteins containing these sugars. These results clearly show that N-linked glycans, present in both the first and third constant regions of the delta heavy-chain domains, are prerequisites for binding of IgD to IgD receptors.
Department of Pathology, Kaplan Cancer Center, New York University School of Medicine, NY 10016.
A R
AR
Amin
S M
SM
Tamma
J D
JD
Oppenheim
F D
FD
Finkelman
C
C
Kieda
R F
RF
Coico
G J
GJ
Thorbecke
D000818:Animals; D001667:Binding, Competitive; D006031:Glycosylation; D007127:Immunoglobulin Constant Regions / Q000378:metabolism; D007072:Immunoglobulin D / Q000378:metabolism*; D007128:Immunoglobulin Fragments / Q000276:immunology / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism; D037102:Lectins; D051379:Mice; D008815:Mice, Inbred Strains; D037121:Plant Lectins; D011961:Receptors, Fc; D011971:Receptors, Immunologic / Q000378:metabolism*; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology*
C045475:Griffonia simplicifolia lectins; D007127:Immunoglobulin Constant Regions; D007072:Immunoglobulin D; D007128:Immunoglobulin Fragments; D007143:Immunoglobulin Heavy Chains; D037102:Lectins; D037121:Plant Lectins; D011961:Receptors, Fc; D011971:Receptors, Immunologic; C050855:immunoglobulin D receptor