Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America.
PLoS One. 2018 Jun 27;13(6):e0199683. doi: 10.1371/journal.pone.0199683. eCollection 2018.
Many broadly neutralizing antibodies (bnAbs) bind to conserved areas of the hemagglutinin (HA) stalk region and can inhibit the low pH induced HA conformational changes necessary for viral membrane fusion activity. We developed and evaluated a high-throughput virus-free and cell-free ELISA based low pH induced HA Conformational Change Inhibition Antibody Detection Assay (HCCIA) and a complementary proteinase susceptibility assay. Human serum samples (n = 150) were tested by HCCIA using H3 recombinant HA. Optical density (OD) ratios of mAb HC31 at pH 4.8 to pH 7.0 ranged from 0.87 to 0.09. Our results demonstrated that low pH induced HA conformational change inhibition antibodies (CCI) neutralized multiple H3 strains after removal of head-binding antibodies. The results suggest that HCCIA can be utilized to detect and characterize CCI in sera, that are potentially broadly neutralizing, and serves as a useful tool for evaluating universal vaccine candidates targeting the HA stalk.
许多广谱中和抗体（bnAbs）结合到血凝素（HA）茎区域的保守区域，并且可以抑制低 pH 诱导的 HA 构象变化，该变化是病毒膜融合活性所必需的。我们开发并评估了一种基于高通量无病毒和无细胞的 ELISA 的低 pH 诱导的 HA 构象变化抑制抗体检测分析（HCCIA）和互补的蛋白酶敏感性分析。使用 H3 重组 HA 通过 HCCIA 对 150 个人类血清样本进行了测试。在 pH 4.8 至 pH 7.0 时，单抗 HC31 的光密度（OD）比值范围为 0.87 至 0.09。我们的结果表明，低 pH 诱导的 HA 构象变化抑制抗体（CCI）在去除头部结合抗体后中和了多种 H3 株。结果表明，HCCIA 可用于检测和表征潜在广谱中和的血清中的 CCI，并可作为评估针对 HA 茎的通用疫苗候选物的有用工具。
