Fan Yan-Ying, Yang Bin-Yan, Wu Chang-You
Dept. of Immunology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.
Immunol Invest. 2008;37(1):79-96. doi: 10.1080/10826080701690714.
Natural killer cells (NK) from umbilical cord blood (CB) play an important role in allogeneic stem cell transplantation and defending infections of newborn. Based on the surface expression of CD56 and CD16 or inhibitory and activatory receptors, NK cells could be subdivided into various subsets with distinct functions. To investigate the biological characterization of NK subsets, the phenotypes and intracellular proteins in freshly isolated CB NK subsets were analyzed at the single cell level by flow cytometry in current study. The production of IFN-gamma and cytotoxicity against K562 target cells were also evaluated after stimulation with IL-12. The results showed that NK cells from CB could be divided into four subsets on the basis of CD56 and CD16 expression. Interestingly, CB NK cells expressed CD45RA but not CD45RO molecules that is similar to the naïve T cells. Moreover, CD27, a memory T cell marker, highly expressed on CD56(hi)CD16- NK cells. The killing-associated molecules, NKG2A, NKG2D, CD95 and the intracellular granzyme B and perforin were heterogeneously expressed among the 4 subsets. Addition of IL-12 into cultures resulted in the induction of IFN-gamma expression by CD56(hi)CD16- and CD56(lo)CD16- subsets and the enhancement of NK cytolytic activity. Taken together, this study elucidated the heterogeneity in phenotypes and biological functions of CB NK cells.
脐带血（CB）中的自然杀伤细胞（NK）在异基因干细胞移植和抵御新生儿感染中发挥着重要作用。基于CD56和CD16的表面表达或抑制性和激活性受体，NK细胞可细分为具有不同功能的多个亚群。为了研究NK亚群的生物学特性，在本研究中通过流式细胞术在单细胞水平分析了新鲜分离的CB NK亚群中的表型和细胞内蛋白。在用IL-12刺激后，还评估了IFN-γ的产生以及对K562靶细胞的细胞毒性。结果表明，CB来源的NK细胞可根据CD56和CD16的表达分为四个亚群。有趣的是，CB NK细胞表达CD45RA但不表达CD45RO分子，这与幼稚T细胞相似。此外，记忆T细胞标志物CD27在CD56(hi)CD16- NK细胞上高度表达。杀伤相关分子NKG2A、NKG2D、CD95以及细胞内颗粒酶B和穿孔素在这4个亚群中呈异质性表达。在培养物中添加IL-12导致CD56(hi)CD16-和CD56(lo)CD16-亚群诱导IFN-γ表达，并增强NK细胞的溶细胞活性。综上所述，本研究阐明了CB NK细胞在表型和生物学功能上的异质性。
