Amaranthus L.-derived exosome-like nanoparticle (PELN) treatment resulted in an increased abundance of Lactobacillus reuteri and indole derivatives, which activated AhR in conventional CD4+ T cells, leading to the down-regulation of Zbtb7b expression, differentiation of conventional CD4+ T cells into double-positive (DP) CD4+CD8+ T cells, and ultimately the attenuation of DSS-induced colitis in C57 mice (87). Here, CD4 is linked to colitis.