fig2

Figure 2. FAP⁺CAFs promote the polarization of naive CD4⁺ T cells toward Th2 by secreting IL-31. (A) Schematic of the co-culture model of naive CD4⁺ T cells and FAP⁺CAFs; (B) Flow cytometric analysis of CCR4 expression changes in naive CD4⁺ T cells after co-culture with FAP⁺CAFs; (C) Positive correlation between IL-31 expression levels in peripheral blood and the abundance of FAP⁺CAFs in tumor tissues; (D) To clarify the effect of FAP on IL-31 expression in CAFs, FAP expression was upregulated in isolated CAFs from gastric cancer tissues using lentiviral vectors; (E and F) Upregulation of FAP expression in CAFs was accompanied by increased IL-31 mRNA and protein expression (n = 3); (G) Flow cytometric analysis of whether the Th2 polarization (CCR4 expression) of naive CD4⁺ T cells mediated by FAP⁺CAFs can be blocked by IL-31 antibodies; (H) Flow cytometric analysis of the effect of rh-IL-31 on CCR4 expression in naive CD4⁺ T cells. ^*P < 0.05; ^**P < 0.01; bars: means ± standard deviation. CAFs: Cancer-associated fibroblasts.