Extended Data Figure 3. Fate mapping T-bet-expressing Treg cells during infectious challenge.

a, Preferential expansion of CD44^hiRFP⁻ vs. CD44^hiRFP⁺ CD4 effector T cells during Nippostrongylus brasiliensis (Nb) infection. Flow cytometry analysis of splenic (above) and lung (below) CD4⁺Thy1.1⁻ cells from PBS- (left) and Nb- (right) challenged mice. b, Flow cytometry of splenic CD4⁺ Thy1.1⁺ (left) and Thy1.1⁻ (right) cells of PBS- (above) and Lm- (below) challenged mice, as indicated in Fig 2a. Numbers indicate percent RFP⁺ (left) and YFP⁺ (right) cells. c, (Above) schematic of experiment. CD44^loCD62L^hiRFP⁻, CD44^hiRFP⁻, and CD44^hiRFP^hiCXCR3^hi CD4⁺Thy1.1⁺ cells were FACS-sorted from pooled spleens and lymph nodes of Tbx21^RFP-CreERT2 mice and transferred into lymphoreplete hosts one day before PBS or Lm challenge. (Below) Flow cytometry of transferred populations (indicated on left) on d9 in spleens of PBS- (left) or Lm- (right) challenged hosts. d, Representative histograms of RFP and CXCR3 expression on total CD4⁺Thy1.1⁺ (shaded histograms) or Th1.1⁺YFP⁺ (open histograms) cells from spleens of PBS- (black) or Lm- (red) challenged mice, as indicted in Fig 2a. e–g, eGFP expression in PBS or Lm challenged Tbx21^RFP-CreERT2IL-10^eGFP mice. e, Schematic of tamoxifen (tx) administration to Tbx21^RFP-CreERT2IL10^eGFP/WT mice for data shown in (f,g). f, Flow cytometry of Treg (above) and YFP⁺ Treg (below) cells in spleens of PBS (left) and Lm (right) treated mice. g, (Left) percent RFP^-eGFP⁺ and RFP⁺eGFP⁺ among Treg cells, as gated in (f, above); (right) percent eGFP⁺ cells among YFP⁺ Treg cells, as gated in (f, below). h, Schematic of Lm reinfection in Tbx21^RFP-CreERT2IL10^eGFP/WT mice for data shown in (i,j); 1^o and 2^o indicate primary and secondary challenge, respectively. i, Flow cytometry of cells in Tbx21^RFP-CreERT2IL-10^eGFP mice on d65, treated as indicated above. j, Percent RFP⁻eGFP⁺ and RFP⁺eGFP⁺ cells among Thy1.1⁺ cells, as gated in (i). All data are representative of ≥ 2 experiments, n≥ 2 mice per group each. Bars, mean±s.e.m. Two-tailed t test (NS – not significant).