Carding S R, West J, Woods A, Bottomly K
Section of Immunology, Howard Hughes Medical Institute, New Haven, CT 06510.
Eur J Immunol. 1989 Feb;19(2):231-8. doi: 10.1002/eji.1830190203.
Studies of cloned CD4+ T cell lines have shown that they can be separated into two distinct subsets with distinctions in their functional capabilities and by the differential release of either interleukin 2 (IL 2) (TH1/inflammatory type) or IL 4 (TH2/helper type) upon activation. To establish if in vivo-derived CD4+ T cells can exhibit distinct subsets we have investigated whether normal CD4+ T cells demonstrate differential expression of IL 2 and IL 4 mRNA, and secretion of IL 2 and IL 4 after primary stimulation in vitro. Utilizing the technique of in situ hybridization IL 2 and IL 4 gene expression in individual CD4+ T cells was readily detectable after concanavalin A (Con A) phytohemagglutinin (PHA) or pokeweed mitogen (PWM)-mediated activation. The frequencies of activated T cells producing IL 2 and IL 4 mRNA after Con A or PHA activation were approximately equivalent (30-40% of cells); however, after PWM activation the number of CD4+ T cells expressing IL 4 mRNA (78%) was more than twofold greater than the number of cells producing IL 2 mRNA (30%). Maximal levels of IL 2 gene expression occurred 24 h after mitogen activation whereas the highest levels of IL 4 mRNA were not detected until 48 h after mitogen activation. Similar distinctions in the kinetics of IL 2 and IL 4 secretion after mitogen activation were also found demonstrating good concordance in the observed expression of IL 2 and IL 4 mRNA and the levels of secreted lymphokines detected by bioassay. Most importantly, we have shown by in situ hybridization analysis that the majority of individual CD4+ T cells produce only IL 2 or IL 4 mRNA, and not both, after primary activation in vitro. By contrast, most CD4+ T cells activated in the presence of PMA and ionophore express both IL 2 and IL 4 mRNA. Our studies demonstrate that in normal, non-clonal populations of CD4+ T cells, the production of IL 2 and IL 4 is independently regulated in the majority of cells and appears to be stimulus dependent.
对克隆的CD4 + T细胞系的研究表明，它们可分为两个不同的亚群，其功能能力不同，激活后释放白细胞介素2（IL-2）（TH1/炎症型）或IL-4（TH2/辅助型）的情况也有差异。为了确定体内来源的CD4 + T细胞是否能表现出不同的亚群，我们研究了正常CD4 + T细胞在体外初次刺激后是否表现出IL-2和IL-4 mRNA的差异表达以及IL-2和IL-4的分泌情况。利用原位杂交技术，在伴刀豆球蛋白A（Con A）、植物血凝素（PHA）或商陆有丝分裂原（PWM）介导的激活后，单个CD4 + T细胞中IL-2和IL-4基因表达很容易被检测到。Con A或PHA激活后产生IL-2和IL-4 mRNA的活化T细胞频率大致相当（占细胞的30 - 40%）；然而，PWM激活后，表达IL-4 mRNA的CD4 + T细胞数量（78%）比产生IL-2 mRNA的细胞数量（30%）多两倍以上。有丝分裂原激活后24小时出现IL-2基因表达的最高水平，而直到有丝分裂原激活后48小时才检测到IL-4 mRNA的最高水平。在有丝分裂原激活后IL-2和IL-4分泌动力学上也发现了类似差异，这表明在观察到的IL-2和IL-4 mRNA表达与生物测定检测到分泌的淋巴因子水平之间具有良好的一致性。最重要的是，我们通过原位杂交分析表明，在体外初次激活后，大多数单个CD4 + T细胞仅产生IL-2或IL-4 mRNA，而非两者都产生。相比之下，在佛波酯（PMA）和离子载体存在下激活的大多数CD4 + T细胞同时表达IL-2和IL-4 mRNA。我们的研究表明，在正常的、非克隆的CD4 + T细胞群体中，大多数细胞中IL-2和IL-4的产生是独立调节的，并且似乎依赖于刺激。
