Fig. 5

Granulocytic-MDSC (G-MDSC) inhibit Tfh cell differentiation through the PD-1/PD-L1 pathway under Tfh-cell-polarizing conditions. CD4⁺CD44^lowCD62L^high-naïve T cells were sorted from normal C57BL/6 mice splenocytes by the EasySep Mouse Naïve CD4⁺ T Cell Isolation Kit. G-MDSC and M-MDSC were sorted from Schistosoma japonicum infected mice by the Myeloid-Derived Suppressor Cell Isolation Kit. Naïve CD4⁺ T cells (5 × 10⁵ cells/well) were co-cultured with G-MDSC or M-MDSC at a ratio of 1:2 (T cell/MDSC) in the presence of anti-CD3, anti-CD28, anti-IFN-γ, anti-IL-4, IL-21 in 24-well plates for 5 days. PD-L1 blocking antibodies and isotypes were used at 5 μg/ml. The percentage of CD4⁺CXCR5⁺ Tfh in different groups (a with G-MDSC, c with M-MDSC). Comparison of Tfh in different groups (b with G-MDSC, d with M-MDSC). Data are expressed as the mean ± SD. One-way ANOVA followed by least significant difference test, ****P < 0.0001. For other abbreviations, see Figs. 1, 2 and 4