PRODUCTION OF THE WORKING VIRUS SEED (WVS) FROM THE MASTER VIRUS SEED (MVS) OF NDV-HXP-S EXPRESSING THE SARS-CoV-2 SPIKE PROTEIN FOR QUALIFIED USE IN COVID-19 VACCINE MANUFACTURING

Abstract

Covid-19 is a global pandemic caused by the SARS-CoV-2 virus, posing a significant burden on healthcare systems and impacting the global economy. Therefore, the development of high-quality working virus seed (WVS) lots derived from the master virus seed (MVS) is essential to enable rapid, safe, and effective domestic production of Covid-19 vaccines. A WVS lot was successfully generated from the NDV-HXP-S MVS, a recombinant Newcastle Disease virus (NDV) modified to express the SARS-CoV-2 spike (S) protein, originally developed and supplied by the Department of Microbiology at the Icahn School of Medicine, Mount Sinai, USA. From the MVS, a WVS lot was produced under the designation WS 210521/P1, comprising 200 vials (0,6 mL per vial), with a viral titer of 10^8,83 EID₅₀/ml. The WVS met all quality criteria, including sterility, NDV identification, spike protein identification, absence of Mycoplasma and extraneous viruses (e.g., ALV), and 100% nucleotide sequence identity compared to the MVS. The WVS maintained its quality after 12 months of storage at ≤ -60°C. The virus replication titer was determined at a dilution of 10⁻⁶, with an optimal incubation period of 96 hours.