Figure 3.

Induced CD11b⁺ B cells, but not CD11b⁻ B cells, could increase regulatory T (Treg) cells though recruiting route rather than proliferation in vitro. (a) CD11b⁺ B cells of Peyer's patches (PPs) from day 7 in mice with colitis were sorted with a MoFlo high‐speed cell sorter (Beckman Coulter, Pasadena, CA). Treg cells (CD4⁺ CD25⁺; 2 × 10⁵ cells/well) were purified from naive wild‐type (WT) mice with MicroBeads (Miltenyi Biotec) and were cultured alone or with CD11b⁺ B cells (4 × 10⁵ cells/well) in 48‐well plates for 72 hr in complete RPMI‐1640. The percentage of Ki‐67⁺ Treg cells was determined by FACS. CD11b⁺ B cells and Treg cells were prepared from four mice. (b) The supernatant samples were obtained either from purified CD11b⁺ B cells or CD11b⁻ B cells (3 × 10⁵ cells/well) sorted from PPs on days 4, 7 and 10, from mice with colitis and then cultured in RPMI‐1640 (without fetal bovine serum) for 24 hr. Total PP lymphocyte suspensions (2 × 10⁶ cells/well) were prepared from the respective period (days 4, 7 and 10) of mice with colitis. Supernatants and cell suspensions were separated by Transwell in a 24‐well plate for 4 hr. Percentage and absolute number of Treg cells were determined by FACS. *P < 0·05; **P < 0·01. Results presented as the means of four independent experiments.