Expanded B cell population blocks regulatory T cells and exacerbates ileitis in a murine model of Crohn disease
Timothy S. Olson, … , Fabio Cominelli, Klaus Ley
Timothy S. Olson, … , Fabio Cominelli, Klaus Ley
Published August 1, 2004
Citation Information: J Clin Invest. 2004;114(3):389-398. https://doi.org/10.1172/JCI20855.
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Article Autoimmunity

Expanded B cell population blocks regulatory T cells and exacerbates ileitis in a murine model of Crohn disease

Abstract

SAMP1/YitFc mice develop discontinuous, transmural inflammatory lesions in the terminal ileum, similar to what is found in human Crohn disease. Compared with the mesenteric lymph nodes (MLNs) of AKR control mice, SAMP1/YitFc MLNs contain a 4.3-fold expansion in total B cell number and a 2.5-fold increased percentage of CD4+ T cells expressing the αEβ7 integrin. Although αEβ7+CD4+ T cells possess a regulatory phenotype (CD25+, L-selectinlo, and CD45RBlo), express IL-10, and suppress effector T cell proliferation in vitro, they cannot prevent ileitis development in SCID mice adoptively transferred with effector CD4+ T cells, although the CD4+CD25+ subset, which overlaps with the αEβ7+CD4+ subset, prevents colitis. The αEβ7+CD4+ T cells express high levels of ICOS, a costimulatory molecule that augments B cell function, suggesting their involvement in the increase in B cells, IgA+ cells, and soluble IgA found within the MLNs and ileum of SAMP1/YitFc mice. MLN B cell numbers correlate with ileitis severity in SAMP1/YitFc mice, and cotransfer of SAMP1/YitFc MLN B cells along with CD4+ T cells increases ileitis severity in SCID mice compared with transfer of CD4+ T cells alone. SAMP1/YitFc B cells prevent αEβ7+CD4+ T cells from suppressing effector T cell proliferation. We conclude that SAMP1/YitFc MLN B cells contribute to the development of SAMP1/YitFc ileitis.

Authors

Timothy S. Olson, Giorgos Bamias, Makoto Naganuma, Jesús Rivera-Nieves, Tracy L. Burcin, William Ross, Margaret A. Morris, Theresa T. Pizarro, Peter B. Ernst, Fabio Cominelli, Klaus Ley

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Cotransfer of MLN B cells increases ileitis severity in the CD4+ T cell ...
Cotransfer of MLN B cells increases ileitis severity in the CD4+ T cell adoptive transfer model. (A and B) A total of 5 × 105 CD4+ T cells from pooled SAMP1/YitFc MLNs (n = 6) were injected intraperitoneally into SCID mice either alone (n = 4) or in combination with 2 × 106 SAMP1/YitFc (n = 8) or AKR (n = 4) MLN B cells intravenously. (A) After 6 weeks, SCID mice receiving both SAMP1/YitFc T cells and SAMP1/YitFc B cells had higher chronic and total inflammatory scores than those of mice receiving T cells alone, while mice receiving AKR B cells and SAMP1/YitFc T cells had an intermediate phenotype. (B) Immunostaining of paraffin-embedded ileal sections, revealing an increase in T cell (CD3+ cells) infiltrates in SCID mice receiving cotransfer of B cells from either strain compared with that of mice receiving T cells alone, and an increased neutrophil (GR-1+ cells) infiltrate in mice receiving specifically SAMP1/YitFc B cells. PMN, polymorphonuclear granulocytes.