Exploring Onchocerca volvulus Cysteine Protease Inhibitor for Multi-epitope Subunit Vaccine Against Onchocerciasis: An Immunoinformatics Approach

Onchocerciasis, caused by Onchocerca volvulus, affects more than 37 million people worldwide. Despite the progress achieved with mass drug distribution, suitable vaccines against onchocerciasis are needed to effectively eliminate the infection. The O. volvulus cysteine protease inhibitor (onchocystatin) is an immuno-dominant antigen detected in O. volvulus infections, capable of inducing protective immunity. Here, we explore the onchocystatin for a multi-epitope subunit vaccine candidate targeted against onchocerciasis. A multi-epitope vaccine candidate composed of RS-09 as adjuvant, a CD8+ T cell peptide, a CD4+ T cell peptide and a B cell peptide concatenated with suitable linkers was computationally constructed. Immune simulation of the vaccine response predicted several aspects of antibody-dependent and cellular-mediated immunity with accompanied B cell and helper T cell immune memory development. The levels of lFN-γ and IL-2 were also predicted to be elevated. Collectively, our results suggest that the multi-epitope vaccine construct has the potential to mimic the natural immunity targeted against onchocerciasis and other related filarial infections, and should be considered for further experimental validations.