Ju S T, Ruddle N H, Strack P, Dorf M E, DeKruyff R H
Arthritis Center, Boston University School of Medicine, MA 02118.
J Immunol. 1990 Jan 1;144(1):23-31.
A TNF (TNF-alpha and TNF-beta)-sensitive target, L929, and two TNF-resistant targets, P815 and LK were used to compare the cytolytic activity among subsets of CD4+ (Th) clones. Cytolytic activity was induced with either Con A, CD3-mAb, or Ag-pulsed LK cells. Six Th1 clones are strongly cytolytic against all three targets. In contrast, Th2 clones are either noncytolytic or weakly cytolytic. Although there is an apparent correlation between TNF production, killing of L929 cells, and the killing of TNF-resistant targets, an anti-TNF serum (capable of neutralizing both TNF-alpha and TNF-beta) selectively inhibits CD4 clones to lyse L929 cells, whereas the lysis of P815 or LK cells was unaffected. The continuous presence of noncytotoxic levels of Actinomycin D (AcD) and cycloheximide, but not mitomycin C, cyclosporin A (CsA), or cholera toxin (ChT) inhibits the lysis of Ag-pulsed, Ia-bearing LK cells; indicating a requirement for de novo synthesis of RNA and protein for cytolytic activity. Although pretreatment with AcD, CsA, or ChT strongly inhibits production of IL-2, TNF and IFN-gamma, only clones pretreated with AcD lose cytolytic activity against Ag-pulsed, Ia-bearing LK cells. These observations support a model of TNF-independent killing of TNF-resistant targets. The TNF-independent cytolytic activity does not correlate with serine esterase activity released into media upon activation of CD4 clones. Moreover, the effects of metabolic inhibitors on serine esterase release do not correlate with their effects on cytolytic activity. Collectively, the data demonstrate that activated CD4 cells express two distinct cytolytic activities; a TNF (and IFN-gamma)-mediated cytotoxicity and a TNF (and IFN-gamma)-independent cytolytic activity. Both pathways require de novo synthesis of RNA and protein and appear to be independent of granule enzyme release. Only the TNF-independent cytolytic activity is resistant to CsA and ChT inhibition.
使用一个对肿瘤坏死因子（TNF-α和TNF-β）敏感的靶细胞L929以及两个对TNF耐药的靶细胞P815和LK，来比较CD4⁺（Th）克隆亚群之间的细胞溶解活性。通过刀豆蛋白A（Con A）、抗CD3单克隆抗体（CD3-mAb）或抗原脉冲处理的LK细胞诱导细胞溶解活性。六个Th1克隆对所有三个靶细胞都具有强烈的细胞溶解作用。相比之下，Th2克隆要么无细胞溶解作用，要么细胞溶解作用较弱。尽管TNF产生、对L929细胞的杀伤以及对TNF耐药靶细胞 的杀伤之间存在明显的相关性，但一种抗TNF血清（能够中和TNF-α和TNF-β）可选择性抑制CD4克隆对L929细胞的溶解，而对P815或LK细胞的溶解没有影响。非细胞毒性水平的放线菌素D（AcD）和环己酰亚胺持续存在，但丝裂霉素C、环孢素A（CsA）或霍乱毒素（ChT）不存在时，会抑制抗原脉冲处理的、表达Ia抗原的LK细胞的溶解；这表明细胞溶解活性需要RNA和蛋白质的从头合成。尽管用AcD、CsA或ChT预处理会强烈抑制白细胞介素-2（IL-2）、TNF和γ干扰素（IFN-γ）的产生，但只有用AcD预处理的克隆会失去对抗原脉冲处理的、表达Ia抗原的LK细胞的细胞溶解活性。这些观察结果支持了一种对TNF耐药靶细胞进行非TNF依赖性杀伤的模型。非TNF依赖性细胞溶解活性与CD4克隆激活后释放到培养基中的丝氨酸酯酶活性无关。此外，代谢抑制剂对丝氨酸酯酶释放的影响与其对细胞溶解活性的影响不相关。总体而言，数据表明活化的CD4细胞表达两种不同的细胞溶解活性；一种是TNF（和IFN-γ）介导的细胞毒性，另一种是TNF（和IFN-γ）非依赖性细胞溶解活性。这两种途径都需要RNA和蛋白质的从头合成，并且似乎与颗粒酶的释放无关。只有非TNF依赖性细胞溶解活性对CsA和ChT抑制具有抗性。
