Design of Innovative multiepitope mRNA-based vaccine against Theileria annulata infection in cattle using immunoinformatic and molecular modelling approaches

Theileriosis is a tick-borne disease that affects ruminants in tropical and subtropical areas and causes clinical signs ranging from mild to severe illness. Theileria annulata primarily infects cattle and cause severe economic losses in livestock. Chemotherapeutic agents are used to treat theileriosis in animals; however, these agents can not completely eradicate the pathogen from animals and promote the establishment of carrier status. Vaccination is an essential option for controlling and preventing theileriosis. This study aimed to design an effective vaccine against Theileria annulata infection in cattle using immunoinformatics and modeling approaches. For this purpose, Theileria annulata sporozoite surface antigen was selected as a target protein. Immunoinformatics tools were used to select non-homologous to host (cattle) and antigenic epitopes from the selected protein. The proposed multiepitope vaccine was generated by combining five cytotoxic T cells, six helper T cell epitopes, and four linear B-lymphocyte epitopes. Additionally, peptide RS09 was added as an adjuvant to increase the antigenicity of the proposed candidate. Immunoinformatics analysis of the immunogenicity and physiochemical profile of the proposed vaccine shows its antigenic (1.0120) and nonallergenic, stable, and hydrophilic. Furthermore, the docking study of bovine TLR4 with the proposed vaccine shows a strong interaction between the two molecules with low energy and high stability. The proposed vaccine can be a promising option against Theileria annulata infection in cattle; however, laboratory-based studies are needed to develop the vaccine candidate.