GSK, Rue de l'Institut 89, 1330 Rixensart, Belgium.
GSK, Avenue Fleming 20, 1300 Wavre, Belgium.
Vaccine. 2019 Apr 10;37(16):2208-2215. doi: 10.1016/j.vaccine.2019.03.011. Epub 2019 Mar 15.
Two electrochemiluminescence (ECL) assays were developed which, together, can simultaneously measure serum antibodies against pneumococcal capsular polysaccharides (PnPS) for 17 serotypes. The assays were validated for the 13 PnPS included in the 13-valent pneumococcal conjugate vaccine (PCV13). As recommended by the World Health Organization (WHO), we compared the ECL assays with the WHO reference enzyme-linked immunosorbent assay (ELISA) and derived a threshold corresponding to the 0.35 µg/mL threshold established for the WHO reference ELISA for the non-inferiority comparison and licensure of new PCVs against invasive pneumococcal disease.
A panel of 452 serum samples from children vaccinated with one of the three licensed PCVs was assessed with the ECL assays and the WHO reference ELISA. The ECL assay threshold for the aggregated seven PnPS included in the 7-valent PCV (PCV7) and serotype-specific thresholds were determined using a receiver operating characteristics (ROC) curve-based approach and Deming regression. To evaluate concordance between the ECL assays and the WHO reference ELISA, serostatus agreement rates between both assays and geometric means of the ratios (GMRs) of concentrations obtained with both assays were calculated.
The thresholds for the seven aggregated PCV7 serotypes obtained with the ROC curve-based approach and Deming regression approximated 0.35 µg/mL (0.38 and 0.34 µg/mL, respectively). Individual thresholds for the PCV13 serotypes ranged between 0.24 and 0.51 µg/mL across both approaches. Serostatus agreement rates using a 0.35 µg/mL threshold for both assays were ≥86.9% for all PCV13 serotypes. GMRs ranged between 0.85 and 1.25 for 11/13 serotypes and were <1.29 for the two remaining serotypes.
The ECL assays were comparable to the WHO reference ELISA and offer a sensitive, time- and serum volume-saving method to quantify serotype-specific anti-PnPS antibodies in pediatric sera. A 0.35 µg/mL threshold will be used for each PCV13 serotype to assess PCV immunogenicity in clinical trials.
开发了两种电化学发光（ECL）检测法，这两种检测法可同时检测血清中针对肺炎球菌荚膜多糖（PnPS）的 17 种血清型抗体。这两种检测法针对包含在 13 价肺炎球菌结合疫苗（PCV13）中的 13 种 PnPS 进行了验证。根据世界卫生组织（WHO）的建议，我们将 ECL 检测法与 WHO 参考酶联免疫吸附测定（ELISA）进行了比较，并得出了与 WHO 参考 ELISA 为新的侵袭性肺炎球菌病用 PCV 建立的 0.35μg/mL 阈值相当的阈值。
用 ECL 检测法和 WHO 参考 ELISA 评估了接种三种已许可 PCV 之一的 452 名儿童的血清样本。使用基于受试者工作特征（ROC）曲线的方法和 Deming 回归确定了包含在 7 价 PCV（PCV7）中的七种聚合 PnPS 的 ECL 检测法阈值和血清型特异性阈值。为了评估 ECL 检测法与 WHO 参考 ELISA 之间的一致性，计算了两种检测法之间的血清阳性符合率以及两种检测法获得的浓度比值的几何均数（GMR）。
使用 ROC 曲线和 Deming 回归得出的七种聚合 PCV7 血清型的阈值分别接近 0.35μg/mL（分别为 0.38 和 0.34μg/mL）。两种方法中，PCV13 血清型的个体阈值范围为 0.24 至 0.51μg/mL。使用两种检测法的 0.35μg/mL 阈值，所有 PCV13 血清型的血清阳性符合率均≥86.9%。对于 11/13 种血清型，GMR 范围在 0.85 至 1.25 之间，对于另外两种血清型，GMR 小于 1.29。
ECL 检测法与 WHO 参考 ELISA 相当，为定量儿科血清中针对特定血清型的抗 PnPS 抗体提供了一种敏感、省时且节省血清量的方法。将使用 0.35μg/mL 的阈值来评估每种 PCV13 血清型的 PCV 免疫原性临床试验。
