Smyth M J, Ortaldo J R
Cellular Cytotoxicity Laboratory, Austin Research Institute, Austin Hospital, Heidelberg, Victoria.
J Immunol. 1993 Jul 15;151(2):740-7.
The broad lytic properties of high buoyant density CD4+ and CD8+ T cell subsets were examined by activating these populations with anti-CD3 mAb and IL-2 for 1 to 5 days and testing their cytotoxic activity against various target cells. The effects of a variety of metabolic inhibitors and anti-TNF antibodies were examined to distinguish several different mechanisms of cytotoxicity used by CD4+ and CD8+ T cell effectors isolated from human PBL. In particular, activated CD4+ and CD8+ T cells were cytotoxic when redirected by an anti-nitrophenyl (NP)-anti-CD3 mAb heteroconjugate against NP-modified nucleated target cells (TC) and anucleated SRBC and also lysed L929 in a TNF-alpha-dependent manner. CD4+ and CD8+ T cells displayed distinct pathways of antibody-redirected lysis against NP-EL4, yet common mechanisms of SRBC redirected lysis by CD4+ and CD8+ efforts were implied by a similar pattern of sensitivity to cholera toxin, cyclosporin A (CsA), and EGTA. CsA inhibited CD4+ and CD8+ T cell redirected lysis of SRBC, but not EL4, suggesting that T cells redirectedly lyse nucleated and anucleated TC by different mechanisms. Cholera toxin, CsA, or EGTA pretreatment also significantly inhibited their release of alpha-N-benzyloxycarbonyl-L-lysine-thiobenzylester-esterase activity suggesting that degranulation of CD4+ and CD8+ effectors may be a critical step in their redirected lysis of SRBC. Overall, these findings suggested that activated human PBL CD4+ or CD8+ effectors can lyse TC by at least three distinct mechanisms: 1) a CsA-sensitive redirected lysis of SRBC that correlates with exocytosis and presumably occurs via membrane lesions; 2) a CsA-insensitive redirected lysis of NP-modified nucleated TC that does not appear to involve exocytosis and is metabolically distinct in activated CD4+ and CD8+ T cell effectors; and 3) a direct TNF-dependent lysis of TNF-sensitive TC.
通过用抗CD3单克隆抗体和白细胞介素-2激活高浮力密度CD4+和CD8+ T细胞亚群1至5天，并检测它们对各种靶细胞的细胞毒性活性，来研究这些细胞亚群广泛的溶解特性。研究了多种代谢抑制剂和抗TNF抗体的作用，以区分从人外周血淋巴细胞（PBL）分离出的CD4+和CD8+ T细胞效应细胞所使用的几种不同的细胞毒性机制。特别地，当被抗硝基苯基（NP）-抗CD3单克隆抗体异源缀合物重定向针对NP修饰的有核靶细胞（TC）和无核绵羊红细胞（SRBC）时，活化的CD4+和CD8+ T细胞具有细胞毒性，并且还以TNF-α依赖的方式裂解L929细胞。CD4+和CD8+ T细胞对NP-EL4显示出不同的抗体重定向裂解途径，然而，CD4+和CD8+效应细胞对SRBC重定向裂解的共同机制可通过对霍乱毒素、环孢菌素A（CsA）和乙二醇双四乙酸（EGTA）的相似敏感性模式来暗示。CsA抑制CD4+和CD8+ T细胞对SRBC的重定向裂解，但不抑制对EL4的裂解，这表明T细胞通过不同机制对有核和无核TC进行重定向裂解。霍乱毒素、CsA或EGTA预处理也显著抑制它们的α-N-苄氧羰基-L-赖氨酸-硫代苄酯酯酶活性的释放，这表明CD4+和CD8+效应细胞的脱颗粒可能是它们对SRBC重定向裂解的关键步骤。总体而言，这些发现表明活化的人PBL CD4+或CD8+效应细胞可通过至少三种不同机制裂解TC：1）对CsA敏感的SRBC重定向裂解，其与胞吐作用相关且可能通过膜损伤发生；2）对NP修饰的有核TC的CsA不敏感的重定向裂解，其似乎不涉及胞吐作用，并且在活化的CD4+和CD8+ T细胞效应细胞中代谢上不同；3）对TNF敏感的TC的直接TNF依赖的裂解。
