Designing a multi-epitope subunit vaccine against Fasciola gigantica using cathepsin L by immunoinformatics approach

Abstract

Fascioliasis, caused by the liver fluke Fasciola spp, is a serious zoonotic disease of animals and humans that causes great economic damage globally. Triclabendazole (TCBZ) is the FDA approved sole medicine available for the treatment of the condition, and drug resistance is on the rise. There is no commercially available safe and effective vaccine to protect against this infection. Increasing TCBZ resistance and the lack of an effective vaccination against fascioliasis necessitate vaccine research. Here, Cathepsin L protein of Fasciola spp was employed in the current work to create a potential vaccine candidate utilizing a structural immunoinformatics method. Cathepsin L antigen is a potential vaccine candidate which is safe, non-allergic, highly antigenic, and effective against a variety of parasitic flukes and worms. The cytotoxic T cells, helper T lymphocytes, and B-cell epitopes were chosen to design vaccine for their immunogenicity and binding affinity behavior. The developed vaccine's physicochemical characteristics, allergenicity, and antigenicity were investigated. To determine the vaccine's tertiary structure, homology modeling was used, followed by structural refinement and docking to the toll-like receptor-2 immune receptor. Molecular dynamics simulations revealed that the vaccination and receptor combination had a stable association. Finally, in silico cloning was used to assess the vaccine construct's expression and translation in the E. coli expression system. Experimental evaluation of the designed vaccine in an animal model is needed to confirm the safety and immunogenicity of the developed vaccine. It may result a novel and immunogenic vaccine that may confer protection against Fasciola spp. infection.