CCL19-expressing FRCs and VSMCs in murine lymph nodes. (A and B) Confocal microscopy images showing cross sections of inguinal lymph nodes and the mesenteric lymph node chain from Ccl19-iEYFP⁺ mice. Boxed areas indicate regions of higher magnification micrographs. Microscopy images are stitched tile scans representative for four inguinal and four mesenteric lymph nodes from three independent experiments. Scale bars: 200 µm (A) and 500 µm (B). (C–E) Confocal microscopy images showing the blood vessels in the inguinal and mesenteric lymph nodes at higher magnification. Arrows and arrowheads highlight the localization of VSMC and PRC around the vessel. High-resolution images are representative for three inguinal and three mesenteric lymph nodes from three independent experiments. Scale bars: 10 µm (C and D, left panels), 3 µm (C and D, right panels), and 5 µm (E). (F–L) Flow cytometric analysis of non-hematopoietic cells in peripheral (inguinal, axillary, and brachial) and mesenteric lymph nodes. (F and I) Phenograph clustering projected on UMAP showing CD31⁻ cells from pooled lymph nodes. (G and J) Expression of surface markers used to identify different FRC and VSMC populations projected on the UMAP. (H and K) Quantification of Ccl19-iEYFP⁺ cells gated according to the gating strategy shown in Fig. S2, A and C with pre-gating on CD31⁻ cells. Data are shown as the mean and SEM from n = 11 mice from three independent experiments. (L) Quantification of the relative abundance of different FRC and VSMC populations. Relative abundances were calculated according to the gating strategy shown in Fig. S2, A and C, and data are shown as the mean and SEM from n = 15 mice from four independent experiments. P values were calculated with unpaired Student’s t test.