Development of a pandemic H5N1 influenza vaccine using MDCK suspension cells: A scalable and efficient production platform.

The persistent threat of H5N1 avian influenza pandemics necessitates the development of rapid and scalable vaccine manufacturing platforms as alternatives to traditional egg-based systems. We established a complete process for manufacturing an inactivated H5N1 vaccine using serum-free MDCK suspension cells, incorporating cell-line screening, systematic optimization of infection parameters, and scale-up in a bioreactor. High-titer virus propagation (1:1024 HA titer; 10.07 log10CCID50/mL) was achieved in a 75 L bioreactor within 48 h. A purification process employing ultrafiltration and two-step chromatography effectively reduced host cell protein and DNA to 2.20 µg/mL and 3.92 ng/mL, respectively. In a preliminary immunogenicity assessment, two immunizations with a 15 µg dose induced 100% seroconversion (geometric mean titer GMT = 183). This work demonstrates a scalable and efficient cell-based production platform for generating high-quality H5N1 vaccines, offering a promising strategy for pandemic preparedness.