骨髓源性而非脾源性树突状细胞能够诱导产生调节性T细胞

越来越多的证据表明,树突状细胞(DC)能够通过刺激CD4+T细胞产生调节性T细胞(Treg)而参与免疫耐受。本研究旨在探索骨髓源性DC(bone marrow-derived DC,BM-DC)或脾源性DC(spleen derived DC,spDC)诱导CD4+CD25+FOXP3+Treg产生的可能性。以GM-CSF和IL-4从C57BL/6小鼠骨髓前体细胞诱导产生骨髓未成熟DC(immature DC,imDC);6 d后,imDC经脂多糖(LPS)进一步刺激16 h得到成熟树突状细胞(mature DC,mDC);同时用免疫磁珠从小鼠脾脏分选得到spDC,以这3种DC分别与新鲜分离的BALB/c小鼠脾CD4+T细胞混合培养,诱导CD4+CD25+FOXP3+Treg的产生;用流式细胞仪检测CD4+T细胞中FOXP3的表达,对比分析3种DC诱导产生CD4+CD25+FOXP3+Treg的能力。结果表明:经C57BL/6小鼠骨髓imDC、mDC的刺激,BALB/c小鼠CD4+T细胞中的FOXP3表达率从(8.57±1.14)%分别提高到(15.80±1.35)%、(17.93±1.45)%(P<0.01);经spDC的刺激,BALB/c小鼠的CD4+T细胞中的FOXP3表达率则从(8.57±1.14)%下降到(3.95±0.79)%(P<0.05)。结论:体外诱导的BM-DC而非spDC能够诱导Treg的产生,具有介导免疫耐受的作用。

Bone Marrow-derived Dendritic Cells Rather Than Spleen-derived Dendritic Cells Can Generate Regulatory T Cells

There are many evidences that dendritic cells（DC） can establish and maintain immunological tolerance through inducing the differentiation of regulatory T cells Treg.This study was purposed to explore the possibility to gene-rate Treg from bone marrow-derived DC（BM-DC） or spleen-derived DC（spDC） generated CD4^＋CD25^＋FOXP3^＋ Treg by induction.Bone marrow immature DC（imDC） induced from bone marrow precursor cells of C57BL/6 mice by GM-CSF and IL-4;after culture for 6 day,imDC were stimulated by LPS for additional 16 hours and the mature DC（mDC） have been got;the spDC were collected from spleen of C57BL/6 mice by MACS.Co-culturing fresh BALB/c mouse CD4^＋T cells with these three sorts of DC above mentioned respectively was performed to generate CD4^＋CD25^＋FOXP3^＋ Treg.The expression of FOXP3 in CD4^＋T cells was detected by flow cytometry,and the capacity of different DC generated CD4^＋CD25^＋FOXP3^＋Treg was evaluated.The results showed that stimulated by C57BL/6 immature or mature DC,the positive rate of FOXP3 in BALB/c CD4^＋T cells increased from（8.57±1.14）% to（15.80±1.35）%,（17.93±1.45）% respectively（P0.01）;while stimulated by spDC,the positive rate of FOXP3 in BALB/c CD4^＋T cells decreased from（8.57±1.14）% to（3.95±0.79）%（P0.05）.It is concluded that the BM-DC but not spDC can generate Treg from CD4^＋T cells,BM-DC may mediate immune tolerance rather than the immune response.