Definition of an immunologic response using the major histocompatibility complex tetramer and enzyme-linked immunospot assays
Definition of an immunologic response using the major histocompatibility complex tetramer and enzyme-linked immunospot assays
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DOI：
10.1158/1078-0432.ccr-05-0136
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发表时间：
2006-01-01
影响因子：
11.5
通讯作者：
Ribas, A
中科院分区：
文献类型：
--
作者：
Comin-Anduix, B;Gualberto, A;Ribas, A
目的：使用四聚体和酶联免疫斑点 (ELISPOT) 测定定义免疫反应。实验设计：10 名健康受试者和 21 名黑色素瘤患者（均为 HLA-A*0201）总共捐献 121 份血液样本，以确定四聚体和 ELISPOT 测定的检测下限 (LLD)、分析变异系数 (aCV) 和生理 CV (pCV)。计算平均值、SD 和参考变化值 (RCV)，以定义超出测定不精确性的变化，并在用 ticilimumab (CP-675,206) 阻断 CTLA4 后监测细胞外扩增中测试其应用。 结果：四聚体测定的 LLD 为 0.038% CD8(+) 细胞，ELISPOT 测定中每 105 个外周血单核细胞有 7 个斑点。四聚体测定的 aCV < 10%，ELISPOT 的 aCV 更高 (24.69-36.32%)。基线稳态值存在明显的受试者间变异，这与之前的抗原暴露相关。免疫反应被定义为基线水平低于LLD的受试者的抗原特异性细胞的增加超过平均值+3SD，或者基线水平高于LLD的受试者的抗原特异性细胞的增加超过测定RCV。在四名接受替西木单抗治疗的患者中，注意到 EBV 和 MART1 抗原的抗原特异性 T 细胞扩增超出了测定变异性。结论：可以使用 RCV 评分计算从阴性（低于 LLD）到阳性（高于 LLD）的变化以及超出测定变异性的百分比变化的组合方法，以定义循环抗原特异性 T 细胞中的哪些变化代表对免疫治疗的反应。
Purpose: Define an immunologic response using the tetramer and enzyme-linked immunospot (ELISPOT) assays.Experimental Design: Ten healthy subjects and 21 patients with melanoma (all HLA-A*0201) donated a total of 121 blood samples to determine the lower limit of detection (LLD), analytic coefficient of variation (aCV), and physiologic CV (pCV) of the tetramer and ELISPOT assays. The mean, SD, and reference change value (RCV) were calculated to define changes beyond the assay imprecision, and its application was tested in the monitoring off-cell expansion after CTLA4 blockade with ticilimumab (CP-675,206).Results: The LLD for the tetramer assay was 0.038% CD8(+) cells and seven spots per 105 peripheral blood mononuclear cells for the ELISPOT assay. The aCV of the tetramer assay was < 10% and was higher for the ELISPOT (24.69-36.32%). There was marked between-subject variability on baseline homeostatic values, which was correlated to prior antigen exposure. An immunologic response was defined as an increase beyond the mean + 3 SD in antigen-specific cells for subjects with baseline levels below the LLD, or beyond the assay RCV for baseline levels above the LLD. In four patients receiving ticilimumab, expansions of antigen-specific T cells beyond the assay variability were noted for EBV and MART1 antigens.Conclusions: A combined approach of change from negative (below the LLD) to positive (above the LLD) and a percentage change beyond the assay variability using the RCV score can be computed to define which change in circulating antigen-specific T cells represents a response to immunotherapy.