Figure 1. S. japonicum infection drives Tfh cell generation.

For each of the three independent experiments, six male C57BL/6 mice were infected with 12 cercariae of S. japonicum per mouse. Infected mice were sacrificed at 8 weeks post-infection. (A) Spleens, mesenteric LN, and livers from normal and infected mice were harvested, and cells were stained with CD3-percpcy5.5, CD4-FITC, CXCR5-APC, and PD-1-PE antibodies. CXCR5^highPD-1^high cells were analyzed and data shown are gated on CD4⁺ T cells. Numbers represent the frequency of the boxed population within the CD4⁺ T cell population; (B) Data are expressed as the mean ± SD of 12 mice from three independent experiments, ***, P<0.001 (Student's t-test). (C) The absolute numbers of CXCR5^highPD-1^high cells in spleens, mesenteric LN, and livers from normal and infected mice were calculated. Data are expressed as the mean ± SD of 12 mice from three independent experiments, ***, P<0.001 (Student's t-test). (D) Spleens, mesenteric LN, and livers from normal and infected mice were harvested, and CD4⁺ T cells were MACS purified, surface stained with CXCR5-APC, PD-1-PE, ICOS-pecy5.5 antibodies and subsequently intracellular stained with BCL-6 Alexa Fluor 488 antibody. The expression of Bcl6 and ICOS in CXCR5^highPD-1^highCD4⁺ T cells and CXCR5^lowPD-1^lowCD4⁺ T cells in spleen, mesenteric LN, and livers was evaluated.