Exploring glutathione transferase and Cathepsin L-like proteinase for designing of epitopes-based vaccine against Fasciola hepatica by immunoinformatics and biophysics studies

Fasciolosis is a zoonotic infection and is considered a developing deserted tropical illness threatening ruminant productivity and causing financial losses. Herein, we applied immunoinformatics and biophysics studies to develop an epitope vaccine against Fasciola hepatica using glutathione transferase and Cathepsin L-like proteinase as possible vaccine candidates. Using the selected proteins, B- and T-cell epitopes were predicted. After epitopes prediction, the epitopes were clarified over immuno-informatics screening, and only five epitopes, EFGRWQQEKCTIDLD,RRNIWEKNVKHIQEH, FKAKYLTEMSRASDI, TDMTFEEFKAKYLTE, and YTAVEGQCR—were selected for vaccine construction; selected epitopes were linked with the help of a GPGPG linker and attached with an adjuvant through another linker, EAAAK linker. Cholera toxin B subunit was used as an adjuvant. The ExPASy ProtParam toolserver predicted 234 amino acids, 25.86257 kDa molecular weight, 8.54 theoreticalpI, 36.86 instability index, and −0.424 grand average of hydropathicity. Moleculardocking analysis predicted that the vaccine could activate the immune systemagainst F. hepatica. We calculated negative binding energy values. A biophysicsstudy, likely molecular docking molecular dynamic simulation, further validated thedocking results. In molecular dynamic simulation analysis, the top hit dockedcompounds with the lowest binding energy values were subjected to MDsimulation; the simulation analysis showed that the vaccine and immune cellreceptors are stable and can activate the immune system. MMGBSA of −146.27net energy (kcal/mol) was calculated for the vaccine–TLR2 complex, while vaccine–TLR4 of −148.11 net energy (kcal/mol) was estimated. Furthermore, the C-ImmSimbioinformatics tool predicted that the vaccine construct can activate the immune system against F. hepatica, eradicate the infection caused by F. hepatica, and reduce financial losses that need to be spent while protecting against infections of F. hepatica. The computational immune simulation unveils that the vaccine model can activate the immune system against F. hepatica; hence, the experimental scientist can validate the finding accomplished through computational approaches.