Design of a Multi-Epitope Vaccine against the Glycoproteins of Newcastle Disease Virus by Using an Immunoinformatics Approach.

Newcastle disease (ND) causes major economic losses in poultry farming in Madagascar and many other countries. Previously, vaccines based on attenuated or inactivated Newcastle disease viruses (NDV) have been effective against this disease. However, their efficacy has declined due to viral mutations over time. To address this, two new multi-epitope vaccines (MEV) have been designed using immunoinformatics methods. First, 26 conserved epitopes from the fusion protein and 22 from the hemagglutinin-neuraminidase protein of 12 NDV strains isolated in Madagascar were selected to design the MEV. These epitopes were fused with specific linkers. Additionally, the adjuvant Avian Beta-Defensins-1 and the 6xHis tag were added to the N- and C-terminal ends of the vaccine formulations, respectively. The antigenicity, allergenicity, solubility, and physicochemical properties of the designed MEV were evaluated. Their three-dimensional structures were also modeled. Molecular docking studies and dynamic simulations were then conducted with the chicken Toll-like receptor 7 (TLR7) to assess the binding affinity of the MEV with this receptor. Finally, an immunological simulation was carried out to assess the ability of the candidate vaccine to induce an effective immune response. Through immunoinformatics analysis, both MEVs developed in this study were found to be highly antigenic, nonallergenic, and physicochemically stable. In addition, they showed significant interaction with the TLR7 receptor. They also have the capacity to trigger immune responses and promote the formation of memory cells following immunization. Therefore, these vaccines represent promising candidates for the control of ND. As this is an immunoinformatics study based on