脐血和新生儿外周血CD4^+CD25^+调节性T细胞的表型特征及意义

Phenotypic characters and roles of CD4^+CD25^+ regulatory T cells in human cord blood and newborn peripheral blood

目的探讨脐血和新生儿外周血中CD4+CD25+调节性T细胞的表型特征及其意义。方法以18份脐血和9份新生儿外周血为标本,细胞膜表面抗原采用单抗直接标记法,检测胞内抗原(CD152、FoxP3)时先标记膜表面抗原,固定破膜后再标记胞内抗原,应用多参数流式细胞仪进行检测和结果分析。结果脐血和新生儿外周血中的CD4+CD25+T细胞显示为独立的细胞群,脐血中该群细胞占CD4+T细胞比例为(9.26±2.43)%,新生儿外周血中的比例则为(9.35±2.30)%;在表型方面,大部分是CD45RA+的细胞,同时表达CD62L、胞浆内的CD152,也表达FoxP3,CD4+CD25+FoxP3+占CD4+T细胞比例为(1.92±0.28)%。结论脐血和新生儿外周血中存在着一群单纯且水平较高的CD4+CD25+调节性T细胞,它们可能在发挥对母体非遗传性抗原的耐受及防止母体对胎儿的排斥反应中具有独特的作用。

Objective To explore the phenotypic characteristics and the roles of CD4^＋CD25^＋ regulatory T cells in human cord blood （CB） and newborn peripheral blood.Methods CD4^＋CD25^＋ T cells fractionated from CB of term and newborn peripheral blood were subjected to flow cytometry. Results The cells were one distinct population and expressed CIY25, CD62L, intracellular cytotoxic T- lymphocyte antigen- 4 （CTLA4）, and marily CIMSRA^＋ . FoxP3 protein, but not mRNA, was specifically expressed. The proportion of CD4^＋CD25^＋ of CB CD4^＋ lymphocytcs was （9.26±2.43） %, and of newborn was（9.35 ±2.30） %, while the number of CD4^＋CD25^＋ FoxP3^＋ of CD4^＋ was （ 1.92 ±0.28） %. Conclusion These results suggest that both CB and newborn peripheral blood contain a distinct population of CD4^＋CD25^＋ regulatory T cells with naive phenotype. This subest may induce tolerance to non-inherited maternal antigens （NIMAS） and play a vital role in preventing both fetal rejection and graft-versus-host react （GVHR） towards maternal tissues during pregnancy.