Fig. 1: Polarized CD4+ T naïve-to-Treg development and activation is a tumor-specific characteristic in NPC.

a The UMAP plot of 189,750 T cells with 41 subtypes identified. b The developmental trajectories of CD4+ T cells. c The change of FOXP3 expression through the pseudotime developmental process from CD4+ naïve T cells to three Treg subtypes, modeled by two-sided polynomial regression analysis with the 95% confidence band. d The normalized fractions of CD4+ naïve T cells and three Treg subtypes in NPC tissues (n = 36) versus in NPC peripheral blood (n = 10) or INP tissues (n = 4) (two-sided unpaired t-test). e The Treg suppressive score and T cell naïve score computed from GSE68799 (tumor n = 42, normal n = 3, two-sided unpaired t-test). f The progression-free survival for NPC patients from GSE102349, stratified by the Treg suppressive score (high n = 44, low n = 44, two-sided log-rank test). g Expression of Treg-specific and naïve signatures in CD4+ naïve T cells and Treg subtypes. h Major biological signaling and activities in Treg subtypes computed by GSVA. i Illustration of the in vitro co-culture systems of CD4+ naïve T cells, NPC cells, and NPE cells. j–l The fraction of total FOXP3+ Tregs, and FOXP3+/CTLA4 + activated Treg in the co-culture systems (k, transwell co-culture; l, direct co-culture) with C666 versus with NP460 or NP69 cells (n = 3, two-sided unpaired t test). m The normalized mRNA fold change of Treg lineage- and activation-specific markers in CD4+ naïve T cells co-cultured with C666 versus with NP460 or NP69 cells (n = 3, two-sided unpaired t test). n The change of immunosuppressive factors in the co-culture systems with C666 versus with NP460 or NP69 cells (n = 3, two-sided unpaired t test). The n number represents n biologically independent samples/experiments in each group. The data are presented as the mean ± SD (bar plots), median ± IQR (whiskers = 1.5 × IQR, box & whiskers plots), and KDE (violin plots).