Efficacy and Tolerability of An mRNA Vaccine Expressing gB and pp38 Antigens of Marek’s Disease Virus in Chickens
Currently vaccines against Marek’s disease virus (MDV) prevent death and limit tumor growth in infected birds. However, they do not control virus shedding from the skin and feather follicle epithelial cells. The present study aimed to explore the utility of an mRNA vaccine for conferring immunity against Marek’s disease. Challenge trials were carried out to evaluate the efficacy of different doses of a MDV mRNA vaccine, the necessity of boosting, and the host responses following intramuscular injection of two doses of mRNA vaccines. Tumor incidence, lesion scores, and MDV load in feather tips at 21 days post-infection were significantly decreased after two inoculations of the vaccine compared to the MDV group. Transcriptional analysis showed upregulation of interferons, interferon-stimulated genes, and cytokines in both spleen and lungs within the first 36 hours of the immunization. The results of the present study provide evidence that mRNA vaccines can induce immunity against MD.