Figure 2.

H37Rv-infected macrophages promote Treg cell differentiation. (A) Scheme of the Treg cell differentiation and suppression assay. Immature macrophages were treated with H37Rv and co-cultured with CD4⁺ naïve T cells for 4 days. T cell populations were purified by using anti-CD3 specific antibody coated microbeads. (B and C) The Treg cell phenotype was detected by immunostaining with CD25 and Foxp3. (D) Functional assay of Treg cells for suppressing T cell proliferation. T cells primed by H37Rv-infected BMDMs were co-cultured with CFSE-labeled activated CD4⁺ T cells for 3 days. (E) Cells were co-cultured as in (D) and proliferation was analyzed by [³H]-thymidine incorporation. Data are presented as cpm. All experiments are representative of three similar results. Statistical differences between groups are indicated by the P-values. *P<0.05; **P<0.01.