Effect of hematopoietic S1P lyase deficiency on T-cell proliferation and migration.

<p>(A) The mitotic response of T cells isolated from <i>Sgpl1^−/−</i> chimeras to αCD3/αCD28 (2 µg/mL) or ConA (2 µg/mL) challenge is markedly decreased compared to <i>Sgpl1^+/+</i> transplanted mice (n = 8 per group). (B) <i>In vivo</i> proliferation of CD4⁺ T cells as measured by EdU incorporation is also significantly decreased in the <i>Sgpl1^−/−</i> chimeras (n = 8 per group). (C, D) CCR7, CXCR4 and S1P₁ positive cells were overrepresented in spleen CD4⁺ and CD8⁺ T-cell subsets of <i>Sgpl1^−/−</i> (n = 10–11 per group). (E) Splenocytes of CCL19-challenged <i>Sgpl1^+/+</i> transplanted mice but not <i>Sgpl^−/−</i> chimeras show ConA induced IL-2 release, which corresponds to reduced proliferation (n = 4 per group) (F). (G) Flow cytometry analysis of lymphoid organs and circulation at 48 hours after injection of a 1∶1 mixture of CMTMR labeled <i>Sgpl1^−/−</i> versus CFSE labeled wild type lymphocytes into LDLr^−/− revealed a reduced presence of <i>Sgpl1^−/−</i> lymphocytes in spleen, lymph nodes and blood (WBC, white blood cells) (n = 9). This reduced homing was confirmed by fluorescence microscopic analysis of lymph node (H) and spleen (I), (scale bar: 100 µm, <i>Sgpl1^−/−</i> lymphocytes in red, wild type lymphocytes in green). White bars: wild-type (WT), black bars: <i>Sgpl1^−/−</i> (KO) chimeras. Data are represented as mean ± SEM. *P<0.05, **P<0.01, ***P<0.001 (WT versus KO), ^###P<0.001 (PBS versus CCL19).