Nestin expression marks lymphoid tissue organizer cells. (A–C) GFP expression by CD45−ICAM-1−VCAM-1−(IV−, black), CD45−ICAM-1intVCAM-1int (IVint, red), CD45−ICAM-1highVCAM-1high (IVhigh, blue), and CD45−ICAM-1highVCAM-1int (Ihigh, green) cells derived from day 0 mesenteric lymph node single-cell suspensions from nestin-GFP mice. (C) Quantification of GFP expression by IV−, IVint, IVhigh, and Ihigh cells derived from day 0 mesenteric lymph node single-cell suspensions from nestin-GFP mice (n = 2 individual experiments, at least five animals per group; data are represented as mean ± SEM). (D and E) FACS analysis of IV−, IVint, IVhigh, and Ihigh stromal cells within day 0 mesenteric and peripheral lymph nodes. (D and E) One representative example out of three individual experiments with at least five animals per group. (F) CFU fibroblast capacity of sorted populations of IV−, IVint, IVhigh, and Ihigh cells derived from single-cell suspensions of day 0 mesenteric lymph nodes (n = 2 individual experiments, at least five animals per group; data are represented as mean ± SEM). (G and H) Absolute numbers of CFU fibroblast capacity in both peripheral and mesenteric lymph nodes (G) and absolute numbers of CD45− stromal cells in mesenteric lymph nodes (H) at various time points after birth. Each dot represents a set of lymph nodes obtained from a single mouse (n ≥ 3; ANOVA; **p < 0.01, ***p < 0.001, data are represented as mean). (I) Quantative RT-PCR of genes associated with adipogenic (adipsin and peroxisome proliferator-activated receptor γ2 [PPAR-y]) and osteogenic (alkaline phosphatase [AP]), osteocalcin, osteoglycin, osterix, and RUNX2) differentiation of cultured mesenchymal precursors at day 0 and week 8 after birth. E13.5 precursor cells served as positive control. Data are represented as mean ± SEM, n ≥ 2, unpaired two-tailed t test. *p < 0.05, **p < 0.01 ***p < 0.001. nd, not detected.