title: CD22 is required for formation of memory B cell precursors within germinal centers.
abstract: CD22 is a BCR co-receptor that regulates B cell signaling, proliferation and survival and is required for T cell-independent Ab responses. To investigate the role of CD22 during T cell-dependent (TD) Ab responses and memory B cell formation, we analyzed Ag-specific B cell responses generated by wild-type (WT) or CD22-/- B cells following immunization with a TD Ag. CD22-/- B cells mounted normal early Ab responses yet failed to generate either memory B cells or long-lived plasma cells, whereas WT B cells formed both populations. Surprisingly, B cell expansion and germinal center (GC) differentiation were comparable between WT and CD22-/- B cells. CD22-/- B cells, however, were significantly less capable of generating a population of CXCR4hiCD38hi GC B cells, which we propose represent memory B cell precursors within GCs. These results demonstrate a novel role for CD22 during TD humoral responses evident during primary GC formation and underscore that CD22 functions not only during B cell maturation but also during responses to both TD and T cell-independent antigens.
authors.affiliation: Department of Immunology, School of Medicine, University of Washington, Seattle, Washington, United States of America.
authors.forename: Craig P
authors.initials: CP
authors.lastname: Chappell
authors.affiliation: Department of Immunology, School of Medicine, University of Washington, Seattle, Washington, United States of America.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Draves
authors.affiliation: Department of Immunology, School of Medicine, University of Washington, Seattle, Washington, United States of America.|Department of Microbiology, School of Medicine, University of Washington, Seattle, Washington, United States of America.
authors.forename: Edward A
authors.identifier: http://orcid.org/0000-0001-8061-5475
authors.initials: EA
authors.lastname: Clark
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D018858:Germinal Center / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D054448:Precursor Cells, B-Lymphoid / Q000276:immunology* / Q000378:metabolism; D051918:Sialic Acid Binding Ig-like Lectin 2 / Q000378:metabolism*
chemical_list: D051918:Sialic Acid Binding Ig-like Lectin 2