Chemokine levels on thymic endothelial cells are reduced after irradiation. (A) Unirradiated thymi were sorted into CD45⁻EpCam⁺ TECs, CD45⁻CD31⁺ endothelial cells, and CD45⁺ cells (n = 3). Each population was analyzed for CCL19, CCL21, and CCL25 mRNA expression by qPCR and normalized to glyceraldehyde-3-phosphate dehydrogenase. (B) CD45⁻EpCam⁺ cells were sorted from unirradiated mice or mice that had received 600 cGy of irradiation 24 hours prior (n = 3). RT-PCR of CCL21, CCL19, and CCL25 expression was normalized to glyceraldehyde-3-phosphate dehydrogenase and quantified relative to the unirradiated control. (C-D) Sections (10 μm) were taken from frozen thymi of untreated WT, TBI 600 cGy (24 hours), TBI 600 cGy (2 weeks), and CCL25-deficient mice and stained with antibodies to CD31 (red) and CCL25 (green). Intensities of cross sections were taken across blood vessels (n = 3). Representative microscopy sections are shown. Plot profile (white arrow) of intensities in each channel was generated in Image J and superimposed. Data are represented as mean ± SEM. *P < .05 compared with unirradiated using the Student t test.