Interaction of CD22 with alpha2,6-linked sialoglycoconjugates: innate recognition of self to dampen B cell autoreactivity?
CD22 is a glycoprotein that associates with the B cell antigen receptor and acts as a negative regulator of receptor signaling; its extracellular domain binds alpha2,6-linked sialoglycoconjugates. Here we show that B cell activation by antigen displayed on the surface of a target cell is depressed if the target co-expresses alpha2,6-sialoglycoconjugates: this inhibition is dependent on CD22. Since sialylation is largely a feature of higher eukaryotes with alpha2,6-sialyltransferase increasing during inflammation, we propose that the CD22 / sialoglycoconjugate interaction allows context-dependent B cell activation, possibly acting as a crude discriminator of self in order to dampen B cell autoreactivity and the initiation of autoimmunity.
Lanoue
Astrid
A
Laboratory of Molecular Biology, Medical Research Council, Hills Road, Cambridge CB2 2QH, GB.
Batista
Facundo D
FD
Stewart
Mairi
M
Neuberger
Michael S
MS
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D001324:Autoantigens; D015551:Autoimmunity; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002236:Carbohydrate Conformation; D015815:Cell Adhesion Molecules; D002460:Cell Line; D002645:Chickens; D015870:Gene Expression; D006001:Glycoconjugates / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D006183:H-2 Antigens / Q000378:metabolism; D037102:Lectins; D008213:Lymphocyte Activation; D051379:Mice; D008822:Mice, Transgenic; D009113:Muramidase / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D051918:Sialic Acid Binding Ig-like Lectin 2; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D001324:Autoantigens; C497868:Cd22 protein, mouse; D015815:Cell Adhesion Molecules; D006001:Glycoconjugates; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D037102:Lectins; D012333:RNA, Messenger; D051918:Sialic Acid Binding Ig-like Lectin 2; D012799:Sialyltransferases; D009113:Muramidase; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase