Fig. 1. Tregs compose the main cells expressing Itgβ8 in tumors.

Itgb8-td-Tomato reporter mice were injected with melanoma cells (B16) or breast cancer cells (E0771) in the dermis or in the mammary gland respectively. Eighteen days later tumors were analyzed by flow cytometry. Percentages of the gated populations are mentioned on dot plots and counterplots. a Representative plots illustrate the Itgb8-tdTomato expression in tumors. b Histograms demonstrating the percentages of Itgβ8^pos cells among the hematopoietic compartment (CD45^pos) and the nonhematopoietic compartment (CD45^neg) in five tumors of each. c, e Representative contour plots illustrating the proportion of CD3^pos cells among Itgb8-td-Tomato^pos CD45^pos cells and CD4^pos Foxp3^pos (Tregs) among Itgb8-td-Tomato^pos T cells. d–f Histograms represent the average percentage of T cells among the Itgb8-tdTomato^pos CD45^pos cells and the percentage Tregs among the Itgb8-tdTomato^pos T cells in five tumors of each. g Representative contour plots illustrating the Itgb8-tdTomato expression in Foxp3^pos CD4^pos T cells. h Histograms illustrate the average percentage of Tregs expressing Itgb8-tdTomato from five tumors of each. i, j Itgb8-tdTomato^pos Tregs and Itgb8-tdTomato^neg Tregs were FACS-sorted, and their ability to activate TGF-β using TGF-β signaling reporter cells was measured (i), as well as their ability to express Tgfb1 by RT-qPCR. Graphs illustrate the levels of bio-activated TGF-β expressed in arbitrary unit (Arb.U.) (i), as well as the levels of expression Tgfb1mRNA normalized on Gadph. Error bar, mean ± SD. b, d, f, h are representative of two experiments with five mice injected with each type of tumors per groups Data in (i, j) are representative of two experiments with five animals in total, each mouse providing both types of cells. *P < 0.05 paired two-tailed Student’s t test. ns statistically not significant. ****P < 0.0001 were determined by unpaired two-tailed Student t test. Source data are provided as a Source Data file.