Production of the Bakırköy strain of sheeppox vaccine virus in spinner flasks using an alternative method with Cytodex 1 microcarriers on Vero cells

Sheeppox (SPP) is a highly contagious viral disease that causes significant morbidity and economic losses in small ruminants. Effective control relies on widespread vaccination, yet conventional production methods that utilize monolayer cultures are limited in scalability, making it difficult to meet large-scale vaccine demands. This study aimed to determine optimal and scalable conditions for producing the Bakırköy strain of the sheeppox virus (SPPV) vaccine using Cytodex 1 microcarriers (MCs) in spinner flasks with Vero cells. Vero cells were propagated in serum-supplemented medium, and cell growth, viability, glucose utilization, and metabolite accumulation were monitored during the expansion phase. In both systems, cells were infected with the Bakırköy strain of SPPV vaccine at multiplicities of infection (MOIs) of 0.1 and 1, and viral titers, cell viability, and metabolite levels were evaluated post-infection. Spinner flask cultures supported higher cell densities and maintained cell viability longer than T-flask cultures. Virus replication was more efficient under dynamic conditions, resulting in higher peak titers and an extended productive phase. Metabolite accumulation (lactate and ammonia) did not adversely affect virus yield until they reached critical thresholds. These findings highlight the importance of metabolite control in optimizing SPPV vaccine production. They also demonstrate that Cytodex 1 microcarrier (MC)-based spinner flask cultures offer a robust and scalable alternative to conventional methods. This approach enables prolonged production, higher viral yields, and greater potential for large-scale vaccine manufacturing.