Tite J P, Powell M B, Ruddle N H
J Immunol. 1985 Jul;135(1):25-33.
We previously showed that cloned, antigen-specific, Ia-restricted L3T4a+ T cell lines can be cytolytic for antigen-pulsed B cell lymphoma targets. Such cells can also, under different experimental conditions, activate B cells to proliferate and secrete immunoglobulin. In the present experiments, we show that this functional phenotype is a common one among a panel of cloned T cell lines. In keeping with this finding, freshly isolated, antigen-activated lymph node T cells show similar functional properties. Such cytolytic L3T4a+ T cells differ from classical H-2K/D-restricted cytolytic T cells in two distinct ways. First, Ia-restricted cytolytic T cells can kill bystander targets, whereas H-2K/D-specific cytolytic T cells do not. Second, in testing a panel of target cells by using lectin-mediated cytolysis, Ia-restricted cytolytic clones reveal large differences in target cell susceptibility, whereas all targets are similarly susceptible to H-2K/D-specific killer cells. Finally, evidence is presented that both direct and bystander killing effected by L3T4a+ T cells are mediated by the same soluble factors, in that there is a strong positive correlation of these two activities for individual cloned lines. The relevant mediators appear to be lymphotoxin and IFN-gamma, although the latter molecule by itself is not cytolytic on our target lines.
我们先前表明，克隆的、抗原特异性的、受Ia限制的L3T4a+ T细胞系可对脉冲抗原的B细胞淋巴瘤靶标产生细胞毒性。在不同实验条件下，这类细胞还能激活B细胞增殖并分泌免疫球蛋白。在本实验中，我们表明这种功能表型在一组克隆的T细胞系中很常见。与此发现一致，新鲜分离的、抗原激活的淋巴结T细胞表现出相似的功能特性。这类具有细胞毒性的L3T4a+ T细胞与经典的受H-2K/D限制的细胞毒性T细胞在两个不同方面存在差异。第一，受Ia限制的细胞毒性T细胞可杀伤旁观者靶标，而H-2K/D特异性细胞毒性T细胞则不能。第二，在用凝集素介导的细胞溶解法检测一组靶细胞时，受Ia限制的细胞毒性克隆显示出靶细胞敏感性存在很大差异，而所有靶标对H-2K/D特异性杀伤细胞的敏感性相似。最后，有证据表明L3T4a+ T细胞所产生的直接杀伤和旁观者杀伤均由相同的可溶性因子介导，因为对于单个克隆系而言，这两种活性存在很强的正相关性。相关介质似乎是淋巴毒素和干扰素-γ，尽管后一种分子本身对我们的靶细胞系无细胞毒性。
