title: Siglec-G is a B-1 cell inhibitory receptor and also controls B cell tolerance.
abstract: B cell antigen receptor signaling on B-1 cells is controlled by several inhibitory receptors, including Siglec-G, which is a member of the Siglec (sialic acid-binding immunoglobulin-like lectin) family and inhibits B cell signaling. The inhibitory function of Siglec-G is largely restricted to B-1 cells, as demonstrated by studies of Siglec-G-deficient mice showing a phenotype affecting mostly B-1 cells. Siglec-G-deficient mice show a markedly increased B-1a cell population, enhanced B-1 cell signaling, and a shift in the immunoglobulin repertoire secreted by their B-1 cells. Mouse models have provided evidence that Siglec-G binds to the B cell receptor (BCR) on the B cell surface via interaction with sialic acid ligands. As an inhibitory receptor on B cells, Siglec-G controls B cell tolerance, and deficiency of this protein can increase the severity of autoimmune diseases. Despite its importance on B-1 cells, there is evidence that the control of B cell tolerance by Siglec-G occurs on conventional B-2 cells.
authors.affiliation: Division of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Nitschke
mesh_terms: D000818:Animals; D015551:Autoimmunity / Q000502:physiology; D016175:B-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007108:Immune Tolerance / Q000502:physiology*; D037102:Lectins / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D011947:Receptors, Antigen, B-Cell / Q000276:immunology / Q000378:metabolism*; D063265:Sialic Acid Binding Immunoglobulin-like Lectins
chemical_list: D037102:Lectins; D011947:Receptors, Antigen, B-Cell; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; C522403:Siglecg protein, mouse
keywords: B-1 cell signaling; B-1 cells; inhibitory receptors