(a) t-SNE embedding of all CD4+ T cells (n = 9.7 × 104) derived from fetal intestines (n = 6.6 × 104 cells from 7 samples), fetal livers (n = 1,530 cells from 3 samples), and fetal spleens (n = 3.0 × 104 cells from 3 samples). Colors indicate tissue origin. Downsampling was performed for samples with more than 10,000 CD4+ T cells. (b) Bar graphs showing the quantification of Treg cells and TN cells, TCM cells, and TEM cells among fetal CD4+ T cells across tissues. TN cells: CD45RA+CCR7+; TCM cells: CD45RA-CCR7+; TEM cells: CD45RA-CCR7−. Fetal liver and spleen, n = 3 independent samples; fetal intestine, n = 7 independent samples. Error bars indicate mean ± SEM. **p < 0.01, Kruskal–Wallis test with Dunn’s test for multiple comparisons.