Extended Data Fig. 6: Intestinal and liver CD8⁺ T_RM cells generate systemic responses upon pathogen rechallenge.

a, Graphic scheme depicts settings of rechallenge experiments with adoptively transferred T_RM cells from liver and intestine. In brief, congenically marked T_RM cells were FACS-purified from liver and SI IEL of LCMV-infected mice, respectively, and co-transferred into naïve recipients, which were challenged with LCMV two weeks later. The offspring of the virus-specific (D^b GP33⁺) donor T cells was analyzed at 8 and >30 days p.i. b, Representative flow cytometry plots show expression of the congenic markers CD45.1 and CD45.2 to identify donor SI IEL T_RM-derived (green), donor liver T_RM-derived (turquoise) and host-derived (grey) cells within the D^b GP33⁺ T cell population in the indicated tissues at 8 and >30 days p.i. c, d, Representative flow cytometry plots show (c) expression of CD44 and CD62L and (d) expression of CX3CR1 and KLRG1 on D^b GP33⁺ SI IEL T_RM- (left) and liver T_RM-derived memory T cells (right) in spleen at >30 days after LCMV challenge. e, f, The frequency of (e) CD62L expression and (f) co-expression of KLRG1 and CX3CR1 within the offspring of donor T_RM populations and host D^b GP33⁺ cells were quantified. Two-tailed paired t-test, *P < 0.05; ***P < 0.001. g, Representative flow cytometry plots show expression of CXCR6 and CD69 on D^b GP33⁺ secondary memory cells developing from donor SI IEL T_RM (left) or liver T_RM (right) cells after LCMV challenge. h, The frequency of T_RM cells (CD69⁺ CXCR6⁺) within the donor populations was quantified. Two-tailed paired t-test. Combined data from two independent experiments (n = 9 or 10 mice). Symbols represent individual mice; bars represent the mean. Error bars represent mean ± SEM.