Fig. 3: There is a gut-brain T cells axis at steady state.
a, Absolute counts and proportion of CD45 IV-label negative brain CD4 T cells capable of secreting IFNγ upon stimulation in various aged mice via FACS. **=p<0.01, ****=p<0.0001 by one-way ANOVA (n=3 per group; repeated twice) b, FACS analysis comparing total and IFNγ and IL-17A-secreting brain CD4 T cell numbers in 3, 4- and 8-week-old germ free (GF) and SPF mice. (GF: n= 3 per group. SPF: n=3 per group; pooled 2 experiments) c, Same FACS analysis as b except in GF mice mono-colonized with SFB bacteria and GF controls. (First graph: n=4 per group; repeated once. Second & Third graph: n=8 per group; repeated once) d, Same FACS analysis as in Fig. 2i. (n=8 per group pooled 3 experiments) *=p<0.05, ****=p<0.0001 by two-way ANOVA with Bonferroni’s multiple comparisons test for b, c. e, Degree of T cell receptor (TCR) clonal expansion and Shannon Diversity Index and ACE index per tissue. f, TCR clonal sharing as represented by the alluvial graph and Jaccard index. g, FACS analysis of CD45 IV-negative CD4 T cell numbers in Smarta TCR (Vα2 Vβ8) transgenic mouse. (n= 4 per group; repeated once). h, FACS analysis of brain, meningeal and mLN CD4 T cell numbers in adult Smarta Rag1−/− and Rag1+/− control mice. (left: n=12 per group pooled 3 experiments; right: n=4 per group; repeated once). i, Schematic of adoptive transfer of naïve 7B8 T cells into GF or SFB-treated mice. The absolute number and frequency of TH17 7B8 T cells from brain measured by FACS. (n=5 per group; repeated two times). j, same as i except recipient mice were Jackson Laboratory (no SFB) or Taconic Biosciences (have SFB) C57BL/6 mice. (n=4 per group). *=p<0.05, **=p<0.01, ***=p<0.001 by unpaired parametric t-test for c, h, i, j.