Expanded B cell population blocks regulatory T cells and exacerbates ileitis in a murine model of Crohn disease
J. Clin. Invest. Timothy S. Olson, et al. 114:389 doi:10.1172/JCI20855 [Go to this article.]

Figure 6
SAMP1/YitFc MLN and ileum contain large populations of IgA⁺ cells. (A) SAMP1/YitFc MLN (top) contain considerably more IgA-secreting cells (dark brown spots) and soluble IgA (diffuse light brown) than do AKR MLN (bottom), as shown by immunostaining of paraffin-embedded MLN sections. (B) Left, representative dot plots of B220 versus IgA expression, with quadrant percentages (mean ± SEM), demonstrating an increase in mature B cells (B220hi) and plasmablasts (B220int) expressing IgA in SAMP1/YitFc MLNs (n = 13) versus AKR MLNs (n = 6). *Significantly greater (P < 0.05) than AKR cell percentage. Right, IgM⁺-gated dot plots, with quadrant percentages (mean ± SEM), showing that less than 20% of SAMP1/YitFc (n = 13) or AKR (n = 6) MLN B cells have a CD23^–IgD^– B1 cell phenotype. (C) Low-power view (magnification, ×10) of paraffin-embedded ileal sections immunostained for IgA, showing increased concentrations of IgA-secreting cells (dark brown spots) throughout and increased soluble IgA within the villi (diffuse light brown) in SAMP1/YitFc versus AKR ilea. (D) High-power views (magnification, ×40) show IgA-secreting cells and soluble IgA focally concentrated in the base (left) and the tip (right) of two villi within SAMP1/YitFc ilea.