Ig-independent Ig beta expression on the surface of B lymphocytes after B cell receptor aggregation.
In order for humoral immune responses to develop, B cells must be able to recognize, bind, and internalize Ags. These functions are performed by the BCR, which is also responsible for initiating and transducing activation signals necessary for B cell proliferation and differentiation. We have examined surface expression patterns of individual components of the BCR following anti-Ig- and Ag-induced aggregation. Specifically, the localization and expression levels of the Ag-binding component, surface Ig (sIg), and the Igbeta component of the Igalpha/Igbeta signaling unit were investigated to determine their individual participation in the internalization and signal transduction. Using primary murine B cells, we found that while >95% of the sIg is internalized following anti-Ig-induced aggregation, 20-30% of Igbeta remains on the surface. These results suggest that sIg and Igbeta may function independently following the initial stages of signal transduction.
Kremyanskaya
Marina
M
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Monroe
John G
JG
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D051925:CD79 Antigens; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis / Q000502:physiology; D006801:Humans; D007136:Immunoglobulins / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D011940:Receptor Aggregation / Q000276:immunology*; D011947:Receptors, Antigen, B-Cell / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism
D000888:Antibodies, Anti-Idiotypic; D015703:Antigens, CD; D051925:CD79 Antigens; C497883:CD79B protein, human; C497884:Cd79b protein, mouse; D003432:Cross-Linking Reagents; D000949:Histocompatibility Antigens Class II; D007136:Immunoglobulins; D011947:Receptors, Antigen, B-Cell; C039951:anti-IgD; C044203:anti-IgM