Elevated CXCL12 expression correlates with T cell accumulation in the bone marrow of NOD mice. A. Analysis of chemokine expression in the bone marrow. RNA was isolated from bone marrow of Balb/c (n = 5) and prediabetic NOD (n = 6) mice, pooled, labeled and used as a probe to hybridize with GEArray chemokine array filters. Representative chemiluminescent images from the hybridization are shown. 1, CCL19; 2, CXCL12. B. Quantitation of CXCL12 and CCL19 transcripts by RT-PCR. The same RNA as in A was used in real-time RT-PCR analysis for CXCL12, CCL19 and GAPDH. The relative transcript levels of CXCL12 and CCL19 to GAPDH are shown. C. Comparison of CXCL12 transcript levels in the bone marrow between 4–5 week-old NOD mice (n = 8) and Balb/c mice (n = 6). D. Comparison of CXCL12 transcript levels in the bone marrow among 6–9 week-old Balb/c (n = 5), EA16 (n = 3) and NOD (n = 8) mice. E. CXCR4 expression by CD4 T cells in different organs of Balb/c and prediabetic NOD mice. Cells from BM, LN and SP of Balb/c and prediabetic NOD mice were stained for TCR, CD4, CD45RB and CXCR4. Representative CXCR4 versus CD45RB profiles are shown for TCR+CD4+ cells. The numbers indicate percentages of cells in the gated areas. * p < 0.05.