Pfizer Inc., Collegeville, Pennsylvania, USA.
Pfizer Inc., Pearl River, New York, USA.
mSphere. 2018 Aug 8;3(4):e00127-18. doi: 10.1128/mSphere.00127-18.
This article describes the results of a study designed to bridge the World Health Organization (WHO) pneumococcal enzyme-linked immunosorbent assay (ELISA) platform to the validated Luminex-based 13-plex direct immunoassay (dLIA) platform developed by Pfizer, Inc. Both assay platforms quantify serotype-specific serum IgG antibodies (in micrograms per milliliter) against an international reference standard serum. The primary goal of this study was to determine if the dLIA is a suitable replacement for the ELISA to support clinical vaccine studies that include the evaluation of immune responses to serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F. Serum samples were selected from four pivotal 13-valent pneumococcal conjugate vaccine (13vPnC; Prevnar 13) clinical trials on the basis of their serotype-specific IgG concentrations by ELISA. In these studies, subjects were immunized either with 13vPnC or with 7-valent pneumococcal conjugate vaccine (7vPnC; Prevnar). There were 1,528 of 1,574 selected samples with sufficient remaining volume for reanalysis in the dLIA. A comparison of assay results from the dLIA and ELISA platforms showed clear and robust linear quantitative relationships across all 13 serotypes. In addition, lower IgG antibody concentrations in preimmunization samples were measured in the dLIA, thus allowing better differentiation between preimmunization and low-titer postimmunization samples. Overall, the results showed that the established population-level protective threshold IgG concentration, 0.35 µg/ml of serotype-specific serum IgG antibodies, is appropriate for use for data generated using the dLIA platform developed by Pfizer, Inc., for 10 serotypes: serotypes 1, 3, 4, 6A, 7F, 9V, 14, 18C, 19F, and 23F. On the basis of the extensive bridging analyses, however, the use of dLIA cutoff values of 0.23, 0.10, and 0.12 µg/ml is recommended for serotypes 5, 6B, and 19A, respectively. This adjustment will ensure that the consistency of the established population-level protective threshold IgG concentration is maintained when switching from the ELISA to the dLIA platform. The results of this bridging study demonstrate that the 13-plex dLIA platform is a suitable replacement for the WHO reference ELISA platform. The pneumococcal enzyme-linked immunosorbent assay (ELISA) measures IgG antibodies in human serum, and it is an important assay that supports licensure of pneumococcal vaccines. The immune correlate of protection, 0.35 µg/ml of IgG antibodies, was determined by the ELISA method. Pfizer has developed a new Luminex-based assay platform to replace the ELISA. These papers describe the important work of (i) validating the Luminex-based assay and (ii) bridging the immune correlate of protection (0.35 µg/ml IgG) to equivalent values reported by the Luminex platform.
本文描述了一项旨在将世界卫生组织（WHO）肺炎球菌酶联免疫吸附测定（ELISA）平台与辉瑞公司开发的经过验证的基于 Luminex 的 13 重直接免疫测定（dLIA）平台相衔接的研究结果。这两个检测平台均定量检测针对国际参考标准血清的血清型特异性 IgG 抗体（以微克/毫升为单位）。该研究的主要目标是确定 dLIA 是否适合替代 ELISA，以支持包括评估血清型 1、3、4、5、6A、6B、7F、9V、14、18C、19A、19F 和 23F 免疫应答在内的临床疫苗研究。根据 ELISA 检测的血清型特异性 IgG 浓度，从四项关键性 13 价肺炎球菌结合疫苗（13vPnC；Prevnar 13）临床试验中选择血清样本。在这些研究中，受试者接受了 13vPnC 或 7 价肺炎球菌结合疫苗（7vPnC；Prevnar）免疫接种。有 1574 个选定样本中的 1528 个样本有足够的剩余体积可用于 dLIA 的重新分析。dLIA 和 ELISA 平台的检测结果比较显示，所有 13 种血清型均存在明确而稳健的线性定量关系。此外，dLIA 检测到免疫前样本中的 IgG 抗体浓度较低，从而能够更好地区分免疫前和低滴度免疫后样本。总体而言，结果表明，为使用辉瑞公司开发的 dLIA 平台生成的数据建立的人群保护水平的保护性阈值 IgG 浓度 0.35μg/ml 适用于以下 10 种血清型：血清型 1、3、4、6A、7F、9V、14、18C、19F 和 23F。然而，基于广泛的桥接分析，建议分别为血清型 5、6B 和 19A 使用 dLIA 截断值 0.23、0.10 和 0.12μg/ml。这种调整将确保在从 ELISA 平台切换到 dLIA 平台时，建立的人群保护水平的保护性阈值 IgG 浓度的一致性得以维持。这项桥接研究的结果表明，13 重 Luminex dLIA 平台是替代 WHO 参考 ELISA 平台的合适选择。肺炎球菌酶联免疫吸附测定（ELISA）检测人血清中的 IgG 抗体，是支持肺炎球菌疫苗许可的重要检测方法。保护的免疫相关性，0.35μg/ml 的 IgG 抗体，是通过 ELISA 方法确定的。辉瑞公司开发了一种新的基于 Luminex 的检测平台来替代 ELISA。这些论文描述了重要的工作：（i）验证 Luminex 检测平台，（ii）将保护的免疫相关性（0.35μg/ml IgG）与 Luminex 平台报告的等效值相衔接。
