Pollock R E, Zimmerman S O, Fuchshuber P, Lotzová E
Department of General Surgery, University of Texas M. D. Anderson Cancer Center, Houston 77030.
J Clin Lab Anal. 1990;4(4):274-82. doi: 10.1002/jcla.1860040408.
51Chromium release-derived cytotoxicity data yield curvilinear plots when the x axis displays the effector:target ratio and the y axis displays the percentage of cytotoxicity. To facilitate data analysis, several biomathematical models (simple linear regression, exponential fit, and Von Krogh) have been used to express these cytotoxicity curves as a single numerical value, termed the lytic unit. Other than using raw cytotoxicity data, the lytic unit has been the most common method of data presentation in human and animal tumor immune studies involving natural killer cells, lymphokine-activated killer cells, and cytotoxic T cells. Unfortunately, the models for determining lytic unit values incorporate assumptions and methods of calculation that can result in inaccurate model-predicted cytotoxicity in comparison with the actual observed cytotoxicity data. Even when the model is accurate in predicting cytotoxicity values (i.e., the nonlinear regression-calculated three-parameter Von Krogh model), comparisons between donors of minimally different or highly different cytotoxicity are still fraught with potential error due to statistically verifiable violations of assumptions of parallelism. Although more cumbersome, donor cytotoxicity comparisons using a range of effector:target ratios are not subject to the above problems. Researchers may therefore want to reconsider the use of lytic units when evaluating and reporting cytotoxicity data.
当x轴显示效应细胞与靶细胞比例，y轴显示细胞毒性百分比时，基于51铬释放的细胞毒性数据会产生曲线图形。为便于数据分析，已使用多种生物数学模型（简单线性回归、指数拟合和冯·克罗伊模型）将这些细胞毒性曲线表示为单个数值，即裂解单位。除了使用原始细胞毒性数据外，在涉及自然杀伤细胞、淋巴因子激活的杀伤细胞和细胞毒性T细胞的人类和动物肿瘤免疫研究中，裂解单位一直是最常用的数据呈现方法。不幸的是，用于确定裂解单位值的模型包含的假设和计算方法，与实际观察到的细胞毒性数据相比，可能导致模型预测的细胞毒性不准确。即使模型在预测细胞毒性值方面准确（即非线性回归计算的三参数冯·克罗伊模型），由于统计学上可验证的平行性假设违反，细胞毒性差异极小或极大的供体之间的比较仍充满潜在误差。尽管更繁琐，但使用一系列效应细胞与靶细胞比例进行供体细胞毒性比较不会出现上述问题。因此，研究人员在评估和报告细胞毒性数据时，可能需要重新考虑裂解单位的使用。
