人外周血CD4^+ IL-21^+记忆T细胞的特征

Characterization of memory CD4^+ IL-21^+ T cells in human PBMC

目的:探讨人外周血中白细胞介素21(IL-21)的产生细胞及其特征。方法:分离人外周血单个核细胞(PBMC),分为不刺激或anti-CD3(OKT3)、OKT3+anti-CD28、PMA+ionomycin刺激四个组,流式细胞术(FCM)检测产生IL-21的细胞亚群。PMA+ionomycin刺激PBMC、纯化CD4+、CD4+CD45RA-、CD4+CD45RA+细胞、脐带血单个核细胞(CB-MC),FCM分析产生IL-21细胞的表型特征和IL-21与Th1、Th2、Th17和Th22细胞因子之间的关系。结果:与OKT3、OKT3+anti-CD28相比,PMA+ionomycin能诱导最高量的IL-21产生。产生IL-21的主要细胞为CD4+T细胞,少数CD8+T细胞。CD4+IL-21+T细胞表达CD45RO,不表达CD45RA,其中部分细胞表达CCR6、CCR7或CXCR5。CD4+CD45RA-细胞表达IL-21远高于CD4+CD45RA+细胞。进一步研究表明,PBMC产生IL-21,而CBMC不产生。此外,大约24%的CD4+IL-21+细胞表达IFN-γ,小于10%CD4+IL-21+细胞表达IL-4、IL-17或IL-22。结论:人PBMC在多克隆刺激的条件下,可以诱导IL-21的产生。产生IL-21的主要细胞亚群具有记忆CD4+T细胞的表型。其中一部分CD4+IL-21+T细胞的表型独立于Th1、Th2、Th17和Th22细胞亚群。

AIM： To characterize IL-21-producing T cells in human PBMCs.METHODS： PBMCs from healthy individuals were stimulated with or without anti-CD3（OKT3）,OKT3 coupled with anti-CD28,or PMA coupled with ionomycin.The cell subsets of IL-21-producing T cells were determined by FACS.PBMCs,CD4＋,CD4＋CD45RA-,CD4＋CD45RA＋ or CBMCs were stimulated with PMA coupled with ionomycin.The phenotype of CD4＋IL-21＋ T cells and the correlation of IL-21-producing CD4＋ T cells with Th1,Th2,Th17 and Th22 cell populations were analyzed by FACS.RESULTS： PMA and ionomycin induced the highest level of IL-21 production among the stimuli tested.CD4＋ T cells but not CD8＋ T cells mainly expressed IL-21.CD4＋IL-21＋ T cells expressed CD45RO instead of CD45RA.Some of the CD4＋IL-21＋ T cells expressed CCR6,CCR7 or CXCR5.CD4＋CD45RA-T cells expressed much more IL-21 than CD4＋CD45RA＋ T cells.Furthermore,CD4＋ T cells from PBMCs but not CBMCs,expressed IL-21.Approximately 24% of CD4＋IL-21＋ cells expressed IFN-γ.Less than 10% of CD4＋IL-21＋ cells expressed IL-4,IL-17 or IL-22.CONCLUSION： IL-21 is induced from human PBMCs following various polyclonal stimulations.The majority of IL-21-producing cells in PBMCs are memory CD4＋ T cells.In addition,some of the CD4＋IL-21＋ T cells are distinct from Th1,Th2 and Th17 cells.