Fig 1: NOD thymocytes have reduced expression of S1P lyase 1 (SGPL1). The graphs show the SGPL1 expression in CD4/CD8-defined thymocyte subpopulations in C57BL/6 (black bars) and NOD (white bars) mice, analyzed by flow cytometry. (A) SGPL1 in total thymocytes, as well as CD4+CD8+ double-positive, CD4+ and CD8+ SP subpopulations. Histograms show the SGPL1 staining in NOD (white curve) and C57BL/6 (black curve) CD4+ and CD8+ SP thymocytes. The grey curves represent the negative staining control; (B) SGPL1 in mature CD4+CD62Lhi and CD8+CD62Lhi SP thymocyte subpopulations; (C) SGPL1 expression in CD49e−CD4+CD62Lhi and CD49e−CD8+CD62Lhi SP thymocytes; (D) SGPL1 expression in CD49e+CD4+CD62Lhi and CD49e+CD8+CD62Lhi SP thymocytes; (E) SGPL1, fibronectin (FN) and cytokeratin (CK) expression profile in NOD and SGPL1 expression in C57BL/6 thymus sections. The white dashed lines delimit the giant PVS. C = cortical region; M = medullary region. n = 3 thymi per group. Original magnification, ×100; and (F) SGPL1 fluorescence intensity quantification in the cortex, medulla and giant PVS of NOD (left graph) and in the cortex and medulla of C57BL/6 (right graph) mice, represented by the mean grey value. Total = total thymocytes; DN = CD4−CD8− double-negative; DP = CD4+CD8+ double-positive; CD4+ = CD4+CD8− single-positive; CD8+ = CD4−CD8+ single-positive; MFI = median fluorescence intensity. Results are expressed as mean ± SEM and were analyzed by 2-way ANOVA followed by Tukey’s post-test. Differences were considered statistically significant when * or # p < 0.05; ** or ## p < 0.01; **** or #### p < 0.0001. Asterisks represent a statistically significant difference between C57BL/6 and NOD subpopulations; hash marks represent a statistically significant difference between DP and SP subpopulations in the same mouse strain. n = 8 C57BL/6; n = 8 NOD.