Fig. 5

Tryptophan alters CNS-infiltrating immune cell populations via distinct diet and microbiome-dependent mechanisms. CNS-infiltrating leukocytes were isolated and analyzed by flow cytometry (A) 30 days post-EAE induction in ex-GF GMT recipients harboring the B6 or B6+L. reuteri microbiota randomized to a low- or high-tryptophan diet are in (Fig. 4C–E). Major effects of diet alone including (B, C) count and frequencies of the total CD45⁺HighCD11b⁻ population, D, E TCRb⁺, F, G CD4⁺, H, I CD8⁺ T cells, J, K CD4⁺ IL17 and L, M IFNγ . L. reuteri and tryptophan-dependent immunological response in TCRγδ T cells (N, O) and cells positive for indicated cytokines (P, Q)