InDevR Inc., 2100 Central Ave., Suite 106, Boulder, CO 80301, United States.
Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, United States.
Vaccine. 2018 May 17;36(21):2937-2945. doi: 10.1016/j.vaccine.2018.04.048. Epub 2018 Apr 23.
Practical methods to measure the potency of influenza vaccines are needed as alternatives for the standard single radial immunodiffusion (SRID) assay. VaxArray assays for influenza hemagglutinin (HA) and neuraminidase (NA) have been developed to address this need. In this report, we evaluate the use of these assays to assess the potency of HA and NA of an A/H3N2 subunit vaccine by determining the correlation between the amounts measured by VaxArray and the immunogenicity in mice. The antibody response after one and two doses of five formulations of the vaccine ranging from 5 µg/mL to 80 µg/mL of HA, was measured by hemagglutination inhibition (HAI) and neuraminidase inhibition (NAI) assays. For hemagglutinin, vaccine potency determined by VaxArray was equivalent to potency measured SRID and these amounts were predictive of immunogenicity, with excellent correlation between potency measured by VaxArray and the HAI geometric mean titers (GMT). Likewise, the amount of NA measured by VaxArray was predictive of the NAI GMT. The VaxArray NA assay reported non-detectable levels of intact NA for a sample that had been heat degraded at 56 °C for 20 h, demonstrating that the assay measures the native, active form of NA. Similarly, the HA potency measured by VaxArray in this heat-treated sample was very low when a monoclonal antibody was used to detect the amount of antigen bound. Importantly, the force degraded sample induced low HAI titers and the NAI titers were not measurable, supporting the conclusion that the VaxArray HA and NA assays measure the immunogenic forms of these A/H3N2 antigens. This study indicates that VaxArray assays can be used to assess the potency of HA and NA components in influenza vaccines as a proxy for immunogenicity.
需要实用的方法来衡量流感疫苗的效力，作为标准的单向免疫扩散（SRID）测定的替代方法。已经开发了用于流感血凝素（HA）和神经氨酸酶（NA）的 VaxArray 测定法来满足这一需求。在本报告中，我们通过确定 VaxArray 测量的量与小鼠免疫原性之间的相关性，评估了这些测定法用于评估 A/H3N2 亚单位疫苗的 HA 和 NA 效力的用途。通过血凝抑制（HAI）和神经氨酸酶抑制（NAI）测定法，测量了五剂疫苗（HA 浓度范围为 5μg/mL 至 80μg/mL）中一种 A/H3N2 亚单位疫苗在一次和两次剂量后的抗体反应。通过 VaxArray 测量的血凝素疫苗效力与 SRID 测量的效力相当，并且这些量可以预测免疫原性，VaxArray 测量的效力与 HAI 几何平均滴度（GMT）之间具有极好的相关性。同样，VaxArray 测量的 NA 量可预测 NAI GMT。VaxArray NA 测定法报告了在 56°C 加热 20 小时的热降解样品中不可检测的完整 NA 水平，证明该测定法测量的是 NA 的天然、活性形式。同样，当使用单克隆抗体检测结合的抗原量时，VaxArray 在该热处理样品中测量的 HA 效力非常低。重要的是，强力降解的样品诱导低 HAI 滴度，并且无法测量 NAI 滴度，这支持了 VaxArray HA 和 NA 测定法测量这些 A/H3N2 抗原的免疫原性形式的结论。本研究表明，VaxArray 测定法可用于评估流感疫苗中 HA 和 NA 成分的效力，作为免疫原性的替代指标。
