Bensussan A, Tourvieille B, Chen L K, Dausset J, Sasportes M
Proc Natl Acad Sci U S A. 1985 Oct;82(19):6642-6. doi: 10.1073/pnas.82.19.6642.
Six-day allosensitized human peripheral blood lymphocytes treated for 12-18 hr with phorbol 12-myristate 13-acetate (PMA) were found to lose the capacity to kill the specific target in a standard cell-mediated lympholysis (CML) assay, but they were still effective in their ability to kill the tumor cell line K562. We investigated which antigens on the cell membrane involved in alloimmune recognition might be modified by PMA, since it was found that in a lectin-dependent CML assay, the lytic mechanism was not impaired. For this purpose, T3+, T4+ allospecific cytotoxic T lymphocyte (CTL) clones and either T3+ or T3- natural killer (NK) clones were generated from 6-day allostimulated lymphocytes. The results indicated that PMA inhibited the cytolytic function of both alloimmune CTL and NK T3+ clones. In contrast, PMA did not modify the effector cell function of T3- NK clones. Phenotypic analysis of T-cell surface antigens from T3+ clones showed that T3 molecule expression on the cell membrane was reduced by 80-90% after PMA treatment, whereas expression of both accessory T4 molecules, involved in antigen recognition, and receptor for interleukin 2 was increased. Moreover, the loss of function was transitory and could be restored 4 days after PMA treatment when the T3 molecules were fully reexpressed at the cell surface. Taken together, these data strongly suggest that (i) PMA prevents cell-mediated cytotoxicity by modulating the disulfide-linked heterodimer associated to T3 and described as the receptor for antigen on the cell surface of major histocompatibility complex (MHC) and non-MHC specific CTL clones, without affecting the lytic mechanism per se, and (ii) the expression of the receptor for the antigen present on the tumor cell line K562 is not decreased on T3- NK clones after PMA treatment and must be different from that on T3+ T-cell clones.
研究发现，用佛波醇12 -肉豆蔻酸酯13 -乙酸酯（PMA）处理12 - 18小时的6天同种致敏人外周血淋巴细胞，在标准的细胞介导淋巴细胞溶解（CML）试验中失去了杀伤特异性靶细胞的能力，但它们杀伤肿瘤细胞系K562的能力仍然有效。我们研究了参与同种免疫识别的细胞膜上哪些抗原可能被PMA修饰，因为发现在凝集素依赖性CML试验中，溶解机制未受损。为此，从6天同种刺激的淋巴细胞中产生了T3 +、T4 +同种特异性细胞毒性T淋巴细胞（CTL）克隆以及T3 +或T3 -自然杀伤（NK）克隆。结果表明，PMA抑制了同种免疫CTL和NK T3 +克隆的细胞溶解功能。相比之下，PMA并未改变T3 - NK克隆的效应细胞功能。对T3 +克隆的T细胞表面抗原进行表型分析表明，PMA处理后细胞膜上T3分子的表达减少了80 - 90%，而参与抗原识别的辅助性T4分子以及白细胞介素2受体的表达均增加。此外，功能丧失是暂时的，在PMA处理4天后，当T3分子在细胞表面完全重新表达时，功能可以恢复。综上所述，这些数据强烈表明：（i）PMA通过调节与T3相关的二硫键连接的异二聚体来阻止细胞介导的细胞毒性，该异二聚体被描述为主要组织相容性复合体（MHC）和非MHC特异性CTL克隆细胞表面的抗原受体，而不影响溶解机制本身；（ii）PMA处理后，肿瘤细胞系K562上存在的抗原受体在T3 - NK克隆上的表达并未降低，且一定与T3 + T细胞克隆上的不同。
