Gao Jin, Landgraf Galina, Yuan Yue, Yu Hai, Saeidi Soma, Kang Hyeog, Rakic Martinez Mira, Giurgea Luca, Lugovtsev Vladimir, Gorman Jason, Memoli Matthew, Chen Xi, Ye Zhiping, Daniels Robert
Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
Department of Chemistry, University of California, One Shields Avenue, Davis, CA, USA.
NPJ Vaccines. 2025 Jun 7;10(1):118. doi: 10.1038/s41541-025-01173-2.
Efficient approaches that can help to select vaccine strains for the influenza virus neuraminidase (NA) antigen are currently needed to advance the development of vaccines containing NA. Here, we present a rapid and cost-effective solution-based NA active site proximity assay (NASPA) for measuring NA activity inhibitory (NAI) antibodies. This simplified assay uses large "bulky" NA active site-binding inhibitors to replace the sialylated glycoprotein substrates in common NA enzyme-linked lectin assay (ELLA) approaches. Our results with ferret antisera and monoclonal antibodies against vaccine strain NAs show a strong correlation between NASPA and ELLA titers, and that NASPA titers are not influenced by anti-HA antibodies. Consequently, NASPA can be used with influenza A or B strains and with the latter it revealed incremental antigenic changes in the NAs from recent B Victoria lineage vaccine strains. By coupling NASPA with a simple activity assay, we also found that steric and active site-binding NAI antibodies against circulating NAs are common in adult human sera. Finally, we demonstrate that NASPA can be modified by incorporating novel NA substrate-analog-based inhibitors. Together, these results suggest that NASPA can aid the development of vaccines containing NA by helping to select suitable vaccine strains and profile anti-NA antibody responses.
目前需要有效的方法来帮助选择流感病毒神经氨酸酶（NA）抗原的疫苗毒株，以推动含NA疫苗的开发。在此，我们提出一种基于溶液的快速且经济高效的NA活性位点邻近检测法（NASPA），用于测量NA活性抑制（NAI）抗体。这种简化的检测方法使用大型“ bulky” NA活性位点结合抑制剂来替代常见的NA酶联凝集素检测法（ELLA）中的唾液酸化糖蛋白底物。我们用雪貂抗血清和针对疫苗毒株NA的单克隆抗体所做的结果表明，NASPA和ELLA效价之间有很强的相关性，并且NASPA效价不受抗HA抗体的影响。因此，NASPA可用于甲型或乙型流感毒株，对于乙型流感，它揭示了近期B维多利亚系疫苗毒株的NA中逐渐增加的抗原性变化。通过将NASPA与简单的活性检测相结合，我们还发现针对循环NA的空间位阻和活性位点结合NAI抗体在成人血清中很常见。最后，我们证明可以通过加入新型的基于NA底物类似物的抑制剂来改进NASPA。总之，这些结果表明NASPA可以通过帮助选择合适的疫苗毒株和分析抗NA抗体反应来辅助含NA疫苗的开发。
