An intrinsic propensity of murine peritoneal B1b cells to switch to IgA in presence of TGF-β and retinoic acid.

AimsIn the present study we have investigated the comparative switching propensity of murine peritoneal and splenic B cell subpopulations to IgA in presence of retinoic acid (RA) and TGF-β.Methods and resultsTo study the influence of RA and TGF-β on switching of B cell subpopulations to IgA, peritoneal (B1a, B1b and B2 cells) and splenic (B1a, marginal zone, and B2) B cells from normal BALB/c mice were FACS purified, cultured for 4 days in presence of RA and TGF-β and the number of IgA producing cells was determined by ELISPOT assay or FACS analysis. In presence of TGF-β, peritoneal B1b cells switched to IgA more potently than other peritoneal B cell subpopulations. When TGF-β was combined with retinoic acid (RA), switching to IgA was even more pronounced. Under these conditions, "innate" B cells like peritoneal and splenic B1 cells and MZ B cells produced IgA more readily than B2 cells. Additionally, high frequency of nucleotide exchanges indicating somatic hypermutation in VH regions was observed. Besides IgA induction, RA treatment of sorted PEC and splenic B cells led to expression of gut homing molecules - α4β7 and CCR9. Intraperitoneal transfer of RA-treated B1 cells into Rag1(-/-) recipients resulted in IgA in serum and gut lavage, most efficiently amongst B1b cell recipients.ConclusionPresent study demonstrates the differential and synergistic effect of RA and TGF-β on switching of different B cell subpopulations to IgA and establishes the prominence of peritoneal B1b cells in switching to IgA under the influence of these two factors. Our study extends our knowledge about the existing differences among B cell subpopulations with regards to IgA production and indicates towards their differential contribution to gut associated humoral immunity

Association between IL-17 and IgA in the joints of patients with inflammatory arthropathies

Hyperactive secretion and pathogenic effects of interleukin (IL)-17 and IgA have been detected in different arthropathies. Recent evidence has revealed that TH17 cytokines regulate mucosal IgA secretion. However, it is unknown whether and how IL-17 mediates synovial IgA production. Here we aim to investigate the connection of synovial IL-17 with IgA production in the joint. In this study we included synovial fluids (SF) from patients with rheumatoid arthritis (RA; n = 66), spondyloarthritis (SpA; n = 18) and osteoarthritis (OA; n = 36). The levels of IL-17, IL-6, transforming growth factor (TGF)-β1, B-cell-activating factor of the TNF family (BAFF) and anti-lipopolyssacharide (LPS) immunoglobulin (Ig)A were investigated by enzyme-linked immunosorbent assay (ELISA). Total IgA was measured by radial immunodiffusion assay. Synovial fluid-derived mononuclear cells (SFMC) were stimulated with bacterial antigens or SF-conditioned media, and cytokines and IgA were analyzed in the supernatants.Fil: Eliçabe, Ricardo Javier. Universidad Nacional de San Luis; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Silva, Juan Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Cs.fisico Matemáticas y Naturales. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Dave, Mabel Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Cs.fisico Matemáticas y Naturales. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Lacoste, Maria Gabriela. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Cs.fisico Matemáticas y Naturales. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Tamashiro, Héctor. Centro Privado de Salud Bolivar en San Luis; ArgentinaFil: Blas, Rodrigo. Medici Consultorios Externos en San Luis; ArgentinaFil: Munarriz, Alicia. Centro Médico Privado CENYR Center San Luis; ArgentinaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Di Genaro, Maria Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Cs.fisico Matemáticas y Naturales. Instituto Multidiciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis; Argentin