Figure 5.

1α,25-dihydroxyvitamin D3 (1,25(OH)₂D3)-mediated up-regulation of CD73 is partially inhibited by anti-transforming growth factor-β (TGF-β). CD4⁺ T cells stimulated [anti-CD3/interleukin-2 (IL-2)] alone (−) or in the presence of 10⁻⁷ m 1,25(OH)₂D3. (a) Day 7 supernatants were harvested and TGF-β bioactivity was assessed using transfected mink lung epithelial cells and a luminescence assay; levels of luminescence were proportional to TGF-β bioactivity (n = 7; paired t-test). (b, c) Cells were cultured with anti-TGF-β (grey) or an isotype control for 14 days. (b) 1,25(OH)₂D3-mediated induction of cd73 gene expression as determined by quantitative RT-PCR (n = 4; two-tailed paired Wilcoxon test). (c i) representative histograms of CD73 expression and cumulative data of the percentage of CD4⁺ CD73⁺ T cells (c ii) and CD73 mean fluorescence intensity (c iii) (n = 5; data assessed by two-way analysis of variance with Sidak's multiple comparison test). *P ≤ 0·05.