Study on mechanism of regulatory T cells induction by IL-10-producing B cells

Objective This study aims to confirm the mechanism of regulatory T cells (Tregs) induced by interleukin (IL)-10-producing B cells. Methods The splenic B cells were isolated from C57BL/6J mice by magnetic-activated cell sorting.Splenic B cells were stimulated by CD40L for 48 h ex vivo, and followed by the addition of LPS, phorbol 12-myristate 13-acetate (PMA), ionomycin and monensin after 43 h. The IL-10 mRNA of splenic B cells after stimulating was detected by reverse transcription-polymerase chain reaction (RT-PCR). These cells were divided into four groups with different culture conditions: Control group, Co-culture group, Transwell group and Anti-IL-10 group.At 72 h of culture, flow cytometry was used to test CD4+ CD25+ Foxp3+ T cells in different groups.IL-10 was tested by enzyme-linked immunosorbent assay (ELISA). Results The expression of IL-10 mRNA of B cells after stimulating was higher than that of unstimulated cells(t=3.130, P<0.05). Compared to the control group and Transwell group, CD4+ CD25+ Foxp3+ T cells were significantly increased in the Co-culture group (q values were 2.338 and 5.650, respectively, all P values<0.05). However, CD4+ CD25+ Foxp3+ T cells in Anti-IL-10 group were significantly lower than Transwell group(q=15.091, P<0.05). The IL-10 protein levels in the Co-culture group were higher than that of other three groups (q values were 10.870, 5.193 and 10.170 respectively, all P values < 0.05), The IL-10 protein levels in the Anti-IL-10 group were different from that of Transwell group(q=4.978, P<0.05). Conclusion The development of Tregs cells from CD4+ T cells is induced by IL-10-producing B cells.This process is partly depending on cell contact. Key words: Interleukins-10; B cells; Regulatory T cells; CD4+ T cells