Figure 6. Irradiation changes the LN ultrastructure and increases the relative density of Ccl19-Cre⁺ stromal cells.

(A) Total cellularity, absolute numbers of CD45⁺ cells, and absolute numbers and frequencies of eYFP⁺ cells in LNs of unirradiated or lethally irradiated (12 Gy) Tg^Ccl19-Cre+ ROSA26^eYFP reporter mice receiving allogeneic BALB/c splenocytes (n = 6 mice/group). **P < 0.01, ***P < 0.001, NS = P > 0.05, by unpaired, 2-tailed Student’s t test. (B) Immunofluorescence microscopy images of LN cryosections from Tg^Ccl19-Cre+ ROSA26^eYFP mice stained for GFP. Cryosections were from unirradiated or lethally irradiated (12 Gy) mice receiving no T cells, syngeneic B6 CD4⁺ T cells, or allogeneic BALB/c CD4⁺ T cells. (C and D) Immunofluorescence microscopy images of LN cryosections from Tg^Ccl19-Cre+ ROSA26^eYFP mice stained for B220 and CD3 (C, top panel); eYFP, CD11b, and CD169 (C, bottom panel); eYFP and PDPN (D, top panel); and eYFP and CD35 (D, bottom panel). Cryosections were from unirradiated or lethally irradiated (12 Gy) mice receiving allogeneic BALB/c CD4⁺ T cells on day 1.5 after transplantation. Data are representative of 2 experiments.