title: Caspase 6 regulates B cell activation and differentiation into plasma cells.
abstract: Caspase (Casp) family proteases regulate not only lymphocyte apoptosis but also lymphocyte activation and development. In this study, we show that Casp6 regulates B cell activation and differentiation into plasma cells by modifying cell cycle entry. B cells from Casp6 knockout (Casp6 KO) mice examined ex vivo have more cells in G(1) than wild-type B cells, and mitogen-induced G(1) entry of Casp6 KO B cells is much faster than that of wild-type B cells. Even so, S phase entry and proliferation are not increased in Casp6 KO B cells. Rather than proliferating, activated Casp6 KO B cells preferentially differentiate into syndecan-1(+) plasma cells and produce Abs. In Casp6 KO mice compared with WT mice, serum levels of IgG1, IgG2a, and IgG2b are increased and Ag-specific Ab responses are also enhanced along with increased percentages of syndecan-1(+) plasma cells. Casp6 may regulate both B cell activation and differentiation by modifying requirements for G(0) B cells to enter G(1).
authors.affiliation: Department of Immunology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Chie
authors.initials: C
authors.lastname: Watanabe
authors.forename: Geraldine L
authors.initials: GL
authors.lastname: Shu
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Zheng
authors.forename: Richard A
authors.initials: RA
authors.lastname: Flavell
authors.forename: Edward A
authors.initials: EA
authors.lastname: Clark
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western; D053178:Caspase 6 / Q000276:immunology / Q000378:metabolism*; D002453:Cell Cycle / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D010950:Plasma Cells / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D053178:Caspase 6