Fig. 3

CD26 surface levels and total protein abundance in MSC(AT) increase with replicative senescence and age. A Western Blot of CD26 protein levels in MSC(AT) extracts from early passage (EP) and late passage (LP) pediatric (n = 2) and adult (n = 3) samples. Data represent mean + SEM, comparisons done with two-tailed Student’s t-test, *p < 0.05; **p < 0.01. B Representative immunohistochemistry image of CD26 protein abundance in EP and LP-MSC(AT). C CD26 geometric mean fluorescence intensity (gMFI) and % CD26^high MSCs in EP and LP-MSC(AT) (6 adult and 4 pediatric MSC(AT), at EP = p4.1 ± 0.6 and LP = p21.0 ± 6.0). Data represent mean ± SD, comparisons done with paired Wilcoxon tests, **p < 0.01. D CD26 gMFI and % CD26^high MSC(AT) in EP-MSC(AT) from pediatric and adult donors (6 pediatric MSC(AT) at p = 4.7 ± 0.5 and 6 adult MSC(AT) p = 3.8 ± 0.4). Data represent mean ± SD, comparisons done with unpaired Mann–Whitney tests, **p < 0.01