title: Cognate B cell signaling via MHC class II: differential regulation of B cell antigen receptor and MHC class II/Ig-alpha beta signaling by CD22.
abstract: Recent studies demonstrate that MHC class II molecules can signal via associated Ig-alphabeta dimers, signal transducers previously thought to function only in B cell Ag receptor (BCR) signaling. Surprisingly, the biologic outputs of MHC class II and BCR ligation (by thymus-dependent Ags) differ, e.g., MHC class II signaling leads to robust proliferation and extension of pseudopods. It seemed possible that these differences might be due, at least in part, to differential use of inhibitory coreceptors thought to modulate membrane Ig signals. In this study, we demonstrate that CD22, an inhibitory BCR coreceptor, neither associates with nor functions in MHC class II/Ig-alphabeta signaling. Interestingly, CD22 is actively excluded from cell surface MHC class II aggregates.
authors.affiliation: Integrated Department of Immunology, University of Colorado Health Sciences Center and National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Mills
authors.forename: John C
authors.initials: JC
authors.lastname: Stolpa
authors.forename: John C
authors.initials: JC
authors.lastname: Cambier
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D001692:Biological Transport; D051925:CD79 Antigens; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D015815:Cell Adhesion Molecules; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D019281:Dimerization; D015536:Down-Regulation / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000378:metabolism / Q000502:physiology*; D007075:Immunoglobulin M / Q000378:metabolism / Q000502:physiology; D037102:Lectins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010766:Phosphorylation; D011233:Precipitin Tests; D011554:Pseudopodia / Q000276:immunology / Q000502:physiology; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism / Q000502:physiology*; D051918:Sialic Acid Binding Ig-like Lectin 2; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D051925:CD79 Antigens; C497868:Cd22 protein, mouse; C497882:Cd79a protein, mouse; C497884:Cd79b protein, mouse; D015815:Cell Adhesion Molecules; D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M; D037102:Lectins; D011947:Receptors, Antigen, B-Cell; D051918:Sialic Acid Binding Ig-like Lectin 2; D014443:Tyrosine; D002118:Calcium