Purification and characterization of recombinant neuraminidase as a potentially broadly protective influenza virus vaccine candidate

Influenza viruses pose a significant public health threat, causing seasonal epidemics and occasional pandemics with substantial morbidity and mortality worldwide. The development of effective vaccines remains crucial for mitigating the impact of influenza virus infections. The influenza virus possesses two glycoproteins on its surface: hemagglutinin, which is immunodominant, and neuraminidase, which is immunosubdominant. Traditional influenza vaccines primarily target the viral surface glycoprotein hemagglutinin to induce protective immunity. However, the high mutation rate of this protein, particularly in response to selective pressure from immune responses, limits the durability and efficacy of current vaccines. Efficient production of influenza vaccines relies on scalable purification processes to ensure safe and efficacious antigens. Neuraminidase (NA), the second glycoprotein of influenza virus, has recently emerged as target for broadly protective protein subunit vaccine formulations, necessitating development of robust manufacturing and characterization methods for this antigen. Here we present a scalable approach for purifying recombinant NA, expressed in insect cells utilizing the baculovirus expression system. Lean purification processes, based on chromatography and tangential flow filtration, achieve high yield and purity while maintaining the target's structural integrity and biological activity. The purified product is characterized through a variety of techniques, which confirm its structural and functional properties, and the consistency of those throughout the experiments performed. Scalability from laboratory to manufacturing scale under good manufacturing practice (GMP) ensures reproducibility, thus advancing the development of recombinant NA-based vaccines for comprehensive influenza control.