ABSTRACT
<p><b>BACKGROUND</b>The sphingosine 1-phosphate (S1P) receptors (S1PRs) are a group of G protein-coupled receptors expressed on the surface of lymphocytes. The interaction between S1P and S1PRs plays a significant role in the migration and distribution of lymphocytes.</p><p><b>OBJECTIVE</b>To investigate the influence of S1PR5 defect on the lymphocytes distribution in mice.</p><p><b>METHODS</b>The distribution of different subsets of lymphocyte in the mice with S1PR5 defect was examined by flow cytometry.</p><p><b>RESULTS</b>Compared with wild type mice, the number of NK cells in the peripheral blood (PB) and spleen (SP) from the mice with S1PR5 defect decreased very significantly 〔PB: 6.4±0.45% vs 2.2±0.47(P<0.01,n=3)；SP: 3.0±0.91% vs 0.68±0.14%(P<0.05,n=3)〕. However, the NK cell number in the bone marrow (BM) and lymphonodes (LN) of the mice with S1PR5 defect increased very significantly 〔BM: 0.97±0.20 % vs 2.6±0.35% (P<0.01, n=3); LN: 0.35±0.16% vs 1.7±0.15% (P<0.01, n=3)〕. The percentages of CD3(+) lymphocyte in peripheral blood, spleen and lymph node were not statistically significantly different between these 2 types of mice 〔PB: 17.3±7.9% vs 17.0±4.6% (P>0.05, n=3); SP: 33.0±6.0% vs 27.4±1.8% (P>0.05, n=3); LN: 42.3±10.7% vs 51.2±2.7% (P>0.05, n=3)〕.</p><p><b>CONCLUSION</b>S1PR5 defect can significantly influence the NK cell distribution.</p>