Hyperresponsive B cells in CD22-deficient mice.
CD22 is a surface glycoprotein of B lymphocytes that is rapidly phosphorylated on cytoplasmic tyrosines after antigen receptor cross-linking. Splenic B cells from mice with a disrupted CD22 gene were found to be hyperresponsive to receptor signaling: Heightened calcium fluxes and cell proliferation were obtained at lower ligand concentrations. The mice gave an augmented immune response, had an expanded peritoneal B-1 cell population, and contained increased serum titers of autoantibody. Thus, CD22 is a negative regulator of antigen receptor signaling whose onset of expression at the mature B cell stage may serve to raise the antigen concentration threshold required for B cell triggering.
O'Keefe
T L
TL
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
Williams
G T
GT
Davies
S L
SL
Neuberger
M S
MS
D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood; D000917:Antibody Formation; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015815:Cell Adhesion Molecules; D005260:Female; D018390:Gene Targeting; D007114:Immunization; D007075:Immunoglobulin M / Q000097:blood; D016130:Immunophenotyping; D037102:Lectins; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010766:Phosphorylation; D011947:Receptors, Antigen, B-Cell / Q000276:immunology / Q000502:physiology; D051918:Sialic Acid Binding Ig-like Lectin 2; D015398:Signal Transduction; D014162:Transfection
D000974:Antibodies, Antinuclear; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C497868:Cd22 protein, mouse; D015815:Cell Adhesion Molecules; D007075:Immunoglobulin M; D037102:Lectins; D011947:Receptors, Antigen, B-Cell; D051918:Sialic Acid Binding Ig-like Lectin 2; D002118:Calcium