Unleashing the immune arsenal: development of broad spectrum multiepitope bluetongue vaccine targeting conserved T cell epitopes of structural proteins.

Bluetongue (BT) is a severe arboviral disease affecting sheep, cows, and other wild ruminants, caused by the Bluetongue virus (BTV). The virus has evolved into over 32 serotypes, rendering existing vaccines less effective. While the structural proteins of this virus represent promising targets for vaccine development, they unfortunately exhibit high amino acid polymorphism and are laden with numerous inhibitory epitopes. However, certain structural proteins such as VP1 and VP7 are highly conserved and may contain epitopes capable of triggering cross-reactive cell-mediated immunity (CMI). In this study, we identified highly conserved MHC-I and -II-restricted T cell epitopes within VP1, VP5, and VP7 BTV proteins and designed multiepitope vaccine constructs using an in silico immunoinformatics pipeline for both laboratory mouse and bovine natural systems. The conserved epitopes utilized in the vaccines are highly antigenic, non-allergenic, non-toxic, and predicted to be capable of inducing IFN-𝛾. Both mouse and bovine vaccines were tethered with Toll-like receptor (TLR)-4-agonist adjuvants, beta-defensin 2–50 S ribosomal unit to stimulate innate immunity for the CMI development. Protein-protein docking analysis suggested favorable binding affinities between the vaccine constructs and TLR4, while 100-nanosecond molecular dynamics simulations supported the structural stability of the complexes. Although these computational findings are promising, all results require experimental validation. Future in vitro and in vivo studies are essential to confirm the immunogenicity, safety, and protective efficacy of the proposed vaccine candidates in target species.