1 Department of Immunology and Microbiology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Københavns Universitet2 Erler Group, BRIC Research Groups, BRIC, Københavns Universitet3 unknown4 Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Københavns Universitet5 Erler Group, BRIC Research Groups, BRIC, Københavns Universitet6 Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Københavns Universitet
Studies reporting beneficial effects of B lymphocytes in autoimmune diseases have been accumulating and a regulatory role for certain B cell subsets is hence getting more and more recognition. Recently, B cells were shown to exhibit a regulatory effect in a T cell transfer model of colitis. Here, B cells exposed to enteroantigen (eAg) ex vivo abrogated the colitogenic effect if co-transplanted with Treg-depleted (CD4+CD25-) T cells into severe combined immune deficiency (SCID) mice. These data may imply a role for B cells that bind eAg (eAg+ B cells) in the immunopathology of colitis. Here, we report the detection of a subset of eAg+ B cells, including both B2 and B1 lineages, and show that these cells are present in all peripheral lymphoid organs of the mouse including the peritoneal cavity. eAg+ B cells are far more efficient as eAg-presenting cells than unfractionated splenocytes or eAg- B cells in causing proliferation of eAg-specific T cells. In comparison with eAg- B cells, eAg+ B cells secrete a significant amount of IL-10 in vitro, suggesting an anti-inflammatory potential. Compared with wild-type B cells, B cell receptor (BCR) transgenic, hen egg lysozyme-specific B cells show inferior eAg binding and T cell stimulatory activity suggesting involvement of the BCR in eAg binding and processing. After activation of CD19(+) B cells by eAg and hybridization with hypoxanthine-aminopterin-thymidine (HAT) sensitive ×63 lymphoma cells followed by cloning at limiting dilution conditions, around 10% of the hybridoma cells secrete eAg-specific antibodies.
Apmis : Acta Pathologica, Microbiologica, Et Immunologica Scandinavica, 2013, Vol 122, Issue 7, p. 616-27