Preijers F W, Tax W J, Wessels J M, Capel P J, De Witte T, Haanen C
Department of Haematology, University Hospital Nijmegen, The Netherlands.
Scand J Immunol. 1988 May;27(5):533-40. doi: 10.1111/j.1365-3083.1988.tb02380.x.
In the context of ex vivo T cell elimination from bone marrow, the anti-T cell cytotoxic potential of immunotoxins (IT) prepared by conjugation of the monoclonal antibodies (MoAb) WT32 (CD3), T101 (CD5), and WT1 (CD7) to ricin A chain was evaluated. The cytotoxicity of IT was based on protein synthesis inhibition in human T cell lines: GH1, CEM, HPB-ALL, and Jurkat, and appeared closely related to the antigen density and internalization rate of and appeared closely related to the antigen density and internalization rate of the IT. Normal unstimulated T cells appeared to be rather insensitive to IT not due to a low antigen density or decreased internalization. The cytotoxicity of IT to T cells could be enhanced considerably by NH4Cl. Treatment of T cells with a cocktail of IT (10(-8) M) and 20 mM NH4Cl resulted in a 5000-fold cytoreduction as measured by clonogenic assays of limiting T cell dilutions, whereas the haematopoietic progenitor cells remained unaltered. Stimulation of T cells with phytohaemagglutinin (PHA) prior to incubation with IT considerably increased the sensitivity to IT treatment. Thus, normal T cells are less sensitive to anti-T cell IT than T cell lines and activated T cells. This suggests that a low protein synthesis is responsible for the resistance to IT. However, a high specific cytotoxicity of IT to normal T cells can be achieved in the presence of 20 mM ammonium chloride.
在从骨髓中进行体外T细胞清除的背景下，评估了通过将单克隆抗体（MoAb）WT32（CD3）、T101（CD5）和WT1（CD7）与蓖麻毒蛋白A链偶联制备的免疫毒素（IT）的抗T细胞细胞毒性潜力。IT的细胞毒性基于对人T细胞系GH1、CEM、HPB - ALL和Jurkat中蛋白质合成的抑制，并且似乎与IT的抗原密度和内化率密切相关。正常未刺激的T细胞似乎对IT相当不敏感，这并非由于抗原密度低或内化减少。NH4Cl可显著增强IT对T细胞的细胞毒性。用IT（10^(-8) M）和20 mM NH4Cl的混合物处理T细胞，通过有限T细胞稀释的克隆形成试验测量，导致细胞减少5000倍，而造血祖细胞保持不变。在用IT孵育之前，用植物血凝素（PHA）刺激T细胞可显著增加对IT处理的敏感性。因此，正常T细胞比对T细胞系和活化T细胞对抗T细胞IT更不敏感。这表明低蛋白质合成是对IT耐药的原因。然而，在存在20 mM氯化铵的情况下，IT对正常T细胞可实现高特异性细胞毒性。
