Cost-Effective Suspension Adaptation of BHK-21 Cells for Scalable FMD Vaccine Production in Resource-Limited Settings

Background: The foot and mouth disease virus (FMDV) remains a significant threat to livestock health and agricultural economies, particularly in endemic regions such as Egypt. Although suspension cultures of BHK-21 cells are widely used for FMD vaccine production. Suspension cells play a vital role in biomanufacturing, but their high cost often limits their accessibility. This straightforward method offers an efficient and economical solution for obtaining BHK-adapted suspension cells that are ideal for large-scale cultivation in bioreactors. Aim: We developed a simplified and cost-effective method for adapting BHK-21 cells to suspension culture using a progressive accelerated rolling system, eliminating the need for microcarriers or complex bioreactor systems. The resulting suspension-adapted cells (BHK-S) were assessed for growth kinetics, sterility, postthaw viability, and their ability to support FMDV replication and 146S antigen production. Methods: Conversion of adherent BHK-21 to BHK suspension was performed, followed by investigation of cell counts, cell viability, and cell morphology and growth curve analysis. Results: BHK-S cells demonstrated robust growth with >95% viability and a density of 2 × 10⁶ cells/ml. After FMDV infection, suspension cultures yielded significantly higher virus titers (>10⁸ TCID₅₀/mL) compared with adherent cultures (106.8 TCID₅₀/mL; p < 0.001). Furthermore, 146S antigen yield was substantially improved, with suspension cultures producing 4.4 µg/mL compared to 1.5 µg/mL in adherent cells. Scale-up to a 10L bioreactor confirmed the stability of growth parameters and viral productivity. Conclusion: This streamlined and scalable approach for adapting BHK-21 cells to suspension culture offers a practical and affordable alternative for FMD vaccine production in resource-limited settings, facilitating the transition from bench-to-bioprocessing scale.