Abetting host immune response by inhibiting rhipicephalus sanguineus Evasin-1: An in silico approach.

The brown dog tick (Rhipicephalus sanguineus) is the most prevalent tick in the world and a well-recognized vector of many pathogens affecting dogs and occasionally humans. Pathogens exploit tick salivary molecules for their survival and multiplication in the vector and transmission to and establishment in the hosts. Tick saliva contains various non-proteinaceous substances and secreted proteins that are differentially produced during feeding and comprise of inhibitors of blood congealing and platelet aggregation, vasodilatory and immunomodulatory substances, and compounds preventing itch and pain. One of these proteins is Evasin-1, which has a high binding affinity to certain types of chemokines. The binding of Evasin-1 to chemokines prevents the detection and immune response of the host to R. sanguineus, which may result in the successful transmission of pathogens. In this study, we screened potential Evasin-1 inhibitor based on the pharmacophore model derived from the binding site residues. Hit ligands were further screened via molecular docking and virtual ADMET prediction, which resulted in ZINC8856727 as the top ligand (binding affinity: -9.1 kcal/mol). Molecular dynamics simulation studies, coupled with MM-GBSA calculations and principal component analysis revealed that ZINC8856727 plays a vital role in the stability of Evasin-1. We recommend continuing the study by developing a formulation that serves as a potential medicine aid immune response during R. sanguineus infestation.