Enhancing Alcelaphine gammaherpesvirus 1 propagation in the MDBK cell line: role of ruxolitinib and reduced incubation temperature.

Alcelaphine gammaherpesvirus 1 (AlHV-1) is the causative agent of malignant catarrhal fever, a fatal disease of cattle prevalent in regions with wildebeest populations. In vitro isolation and propagation of AlHV-1 is laborious and often requires multiple passages to improve the visibility of the cytopathic effect in host cells and increase virus yields. Ruxolitinib increases the replication of some viruses due to inhibition of the IFN-induced antiviral response of infected cells. In this study, the effect of a ruxolitinib-enriched culture medium was tested simultaneously with the effect of a reduced incubation temperature (33 °C) on the propagation of the AlHV-1 strain WC-11 adapted to the MDBK cell line. Ruxolitinib significantly increased the destruction of the cell monolayer during AIHV-1 propagation and significantly increased the virus titre. In addition, the amount of cell-free AIHV-1 particles in the culture medium was enhanced significantly in the presence of ruxolitinib. A reduced incubation temperature (33 °C), either in combination with ruxolitinib-enriched medium or without ruxolitinib, had no significant effect on AIHV-1 growth. These results demonstrate that ruxolitinib enhances the propagation of AlHV-1 strain WC-11 and suggest a broader potential to improve the efficiency of AlHV-1 cell culture-based applications, such as virus isolation, vaccine production, and diagnostics.