Loschko Jakob, Liberator Paul, Findlow Jamie, Yip Jason, Tan Charles, Garcia Karen, Murillo MaryAnn, Gorantla Yamini, Moss Kimberly M, Maniatis Panagiotis, Clark Stephen A, Borrow Ray
Vaccines Research & Development, Pfizer Inc, 401 N Middletown Rd, Pearl River, NY 10965, USA.
Vaccines/Antivirals and Evidence Generation, Pfizer Ltd, Walton Oaks, Dorking Road, Tadworth, Surrey, KT20 7NS, UK.
Diagn Microbiol Infect Dis. 2025 Oct;113(2):116920. doi: 10.1016/j.diagmicrobio.2025.116920. Epub 2025 May 30.
The serum bactericidal antibody using human complement (hSBA) assay, the accepted surrogate measure of meningococcal vaccine efficacy, is limited by human sera and complement requirements. Pfizer developed and validated the flow-cytometry-based Meningococcal Antigen Surface Expression (MEASURE) assay to quantify surface-expressed factor H binding protein (fHbp) levels on intact meningococci. Surface expression of fHbp is correlated with hSBA assay killing by MenB-fHbp (Trumenba)-induced antibody, meaning the MEASURE assay can be used to predict meningococcal serogroup B (MenB) strain susceptibility to antibodies elicited by MenB-fHbp. This study aimed to evaluate interlaboratory precision and reproducibility of the MEASURE assay.
The MEASURE assay was transferred to UK Health Security Agency (UKHSA) and US Centers for Disease Control and Prevention (CDC) laboratories. MEASURE assay results from 42 MenB strains encoding sequence-diverse fHbp variants that express fHbp at different levels were compared between the UKHSA, CDC, and Pfizer laboratories. Intermediate precision within each laboratory was determined.
Pairwise comparisons of fHbp expression levels for all 42 MenB test strains showed >97 % agreement across the 3 laboratories when strains were grouped above or below a mean fluorescence intensity level of 1000, the threshold previously established as indicative of susceptibility to MenB-fHbp-induced antibodies in the hSBA assay. Each laboratory met assay precision criteria of ≤30 % total relative standard deviation.
Quantification of fHbp surface expression using the MEASURE assay is robust and reproducible across different laboratories. Previously determined cutoffs corresponding to predicted susceptibility to vaccine-induced antibodies can be applied to MEASURE data generated across laboratories.
使用人补体的血清杀菌抗体（hSBA）检测是公认的脑膜炎球菌疫苗效力替代指标，但受到人血清和补体需求的限制。辉瑞公司开发并验证了基于流式细胞术的脑膜炎球菌抗原表面表达（MEASURE）检测方法，用于定量完整脑膜炎球菌表面表达的因子H结合蛋白（fHbp）水平。fHbp的表面表达与MenB - fHbp（Trumenba）诱导的抗体在hSBA检测中的杀菌作用相关，这意味着MEASURE检测可用于预测B群脑膜炎球菌（MenB）菌株对MenB - fHbp诱导抗体的敏感性。本研究旨在评估MEASURE检测在不同实验室间的精密度和重现性。
将MEASURE检测方法转移至英国卫生安全局（UKHSA）和美国疾病控制与预防中心（CDC）的实验室。比较了UKHSA、CDC和辉瑞公司实验室对42株编码序列多样的fHbp变体且fHbp表达水平不同的MenB菌株的MEASURE检测结果。确定了每个实验室内部的中间精密度。
当将菌株按平均荧光强度水平1000以上或以下分组时（该阈值先前被确定为在hSBA检测中对MenB - fHbp诱导抗体敏感的指标），对所有42株MenB测试菌株的fHbp表达水平进行两两比较，结果显示3个实验室之间的一致性>97%。每个实验室均符合总相对标准偏差≤30%的检测精密度标准。
使用MEASURE检测方法对fHbp表面表达进行定量在不同实验室中具有稳健性和可重复性。先前确定的与疫苗诱导抗体预测敏感性相对应的临界值可应用于不同实验室生成的MEASURE数据。
