Herrick M V, Pollack S B
J Immunol. 1978 Oct;121(4):1348-52.
Inhibition of antibody-dependent cellular cytotoxicity (ADCC) by autologous lymphocytes was analyzed by using classical techniques for enzyme-substrate interactions. We determined empirically that the interaction of murine spleen cells with antibody-coated targets to produce lysis was analogous to the interactions that have been described for an enzyme with its substrate. Varying numbers of antibody-coated target cells ("substrate") were mixed with a constant number of spleen cells ("enzyme") and the number of target cells killed ("product") was measured as a function of time. By analogy with Michaelis-Menten enzyme kinetics, two parameters of the reaction were determined: Vmax, the maximum velocity of lysis that is proportional to the number of killer cells present, and K1/2, an intrinsic property of the killer cells. These parameters were found to be independent variables. Addition of autologous lymph node cells produced a dose-dependent decrease in Vmax whereas K1/2 was not significantly changed. By analogy with enzyme kinetics, this inhibition is noncompetitive, suggesting that the autologous lymphocytes inactivate the killer cells rather than competing for the cell-cell binding sites.
通过使用酶 - 底物相互作用的经典技术，分析了自体淋巴细胞对抗体依赖性细胞毒性（ADCC）的抑制作用。我们通过实验确定，鼠脾细胞与抗体包被的靶细胞相互作用以产生裂解，类似于已描述的酶与其底物的相互作用。将不同数量的抗体包被靶细胞（“底物”）与恒定数量的脾细胞（“酶”）混合，并测量作为时间函数的被杀死靶细胞数量（“产物”）。类比米氏酶动力学，确定了反应的两个参数：Vmax，即与存在的杀伤细胞数量成比例的最大裂解速度；以及K1/2，杀伤细胞的固有特性。发现这些参数是独立变量。添加自体淋巴结细胞导致Vmax呈剂量依赖性降低，而K1/2没有显著变化。类比酶动力学，这种抑制是非竞争性的，表明自体淋巴细胞使杀伤细胞失活，而不是竞争细胞 - 细胞结合位点。
