Division of Viral Products, Laboratory of DNA Viruses, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.
Influenza Other Respir Viruses. 2024 Oct;18(10):e70024. doi: 10.1111/irv.70024.
The potency of inactivated and recombinant influenza vaccines is measured using the single-radial immunodiffusion (SRID) assay. The strain-specific antigen and antibody potency reagents required for the assay are prepared and distributed by regulatory agencies to ensure vaccine standardization, but timely reagent production is always challenging. This poses unique concerns for rapid pandemic responses. Alternative methods have been described for generating strain-specific potency antibody reagents without the need for live influenza virus, but such methods are infrequently used, suggesting the need for additional antigen expression approaches.
We describe a rapid process using a mammalian expression system to produce recombinant influenza hemagglutinin (rHA). This platform was used to generate rHA from two H5 clade 2.3.4.4 influenza viruses, in both soluble ectodomain or full-length HA forms, and a soluble ectodomain rHA from an influenza H2 virus.
The purified rHAs were used as immunogens to produce HA antibody reagents that were tested for suitability in the SRID assay to accurately measure the potency of inactivated pandemic influenza vaccines. Antibody reagents generated to either ectodomain or full-length rHA worked well in the SRID assay and resulted in vaccine potency values equivalent to those generated with standard reference antibodies.
The results demonstrate that rHA produced from a simple mammalian cell transfection method can be used to generate HA antibody suitable for use in the influenza vaccine SRID potency assay and suggest a practical means by which an extensive library of pandemic reagents can easily be prepared in advance of and during an influenza emergency.
灭活疫苗和重组流感疫苗的效价是通过单放射免疫扩散（SRID）检测来衡量的。该检测所需的针对特定毒株的抗原和抗体效价试剂是由监管机构制备和分发的，以确保疫苗标准化，但及时生产试剂始终具有挑战性。这对快速大流行应对措施提出了独特的关注。已经描述了替代方法来生成无需使用活流感病毒的针对特定毒株的效价抗体试剂，但这种方法很少使用，这表明需要额外的抗原表达方法。
我们描述了一种使用哺乳动物表达系统快速生产重组流感血凝素（rHA）的方法。该平台用于从两种 H5 谱系 2.3.4.4 流感病毒中生成可溶性外域或全长 HA 形式的 rHA，以及一种流感 H2 病毒的可溶性外域 rHA。
纯化的 rHAs 被用作免疫原，用于产生 HA 抗体试剂，这些试剂经过测试适合于 SRID 检测，以准确测量灭活大流行流感疫苗的效价。针对外域或全长 rHA 生成的抗体试剂在 SRID 检测中效果良好，并且产生的疫苗效价值与使用标准参考抗体产生的效价值相当。
结果表明，通过简单的哺乳动物细胞转染方法生产的 rHA 可用于生成适合用于流感疫苗 SRID 效价检测的 HA 抗体，并为在流感紧急情况下提前和期间轻松制备广泛的大流行试剂库提供了一种实用方法。
