title: A small CD11b(+) human B1 cell subpopulation stimulates T cells and is expanded in lupus.
abstract: A primary function of B lymphocytes is immunoglobulin production; however, the therapeutic benefit of B cell depletion in autoimmune diseases previously thought to be T cell mediated suggests that some B cells fulfill other roles in autoimmunity. We examined the recently identified human B1 cell population for T cell stimulatory activity. We found two kinds of B1 cells that are distinguished by multiple surface markers and distinct transcriptomic profiles. In both umbilical cord and adult peripheral blood, a CD11b(+) subset constitutes ~1 out of every 8-10 B1 cells, whereas a CD11b(-) subset constitutes the remaining B1 cells. These B1 cell populations differ functionally. CD11b(-) B1 cells spontaneously secrete much more IgM than CD11b(+) B1 cells. In contrast, CD11b(+) B1 cells express more CD86, and more efficiently stimulate allogeneic CD4(+) T cell expansion, than CD11b(-) B1 cells. The frequency of these CD11b(+) B1 cells is markedly elevated in lupus patients. CD11b(+) B1 cells in lupus patients express more CD86 and have increased T cell-stimulating activity in disease. This work distinguishes a novel, T cell-interacting B1 cell population whose abundance and activity may be a reflection of, and a therapeutic target in, autoimmune disease.
authors: Elmezzi Graduate School of Molecular Medicine, the Feinstein Institute for Medical Research, Manhasset, NY 11030, USA.
authors: Daniel O
authors: DO
authors: Griffin
authors: Thomas L
authors: TL
authors: Rothstein
mesh_terms: D000328:Adult; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D051940:B7-2 Antigen / Q000096:biosynthesis / Q000276:immunology; D039481:CD11b Antigen; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000378:metabolism / Q000628:therapy; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D059467:Transcriptome / Q000276:immunology
chemical_list: D051940:B7-2 Antigen; D039481:CD11b Antigen; C497964:CD86 protein, human; C509295:ITGAM protein, human; D007075:Immunoglobulin M