Computational Prediction of Multi-Epitopes Vaccine from Envelope E Protein against Louping Ill Virus via Reverse Vaccinology

Abstract

Louping ill disease is a zoonotic viral disease caused by louping ill virus in the genus Flavivirus. It belongs to the tick-borne flavivirus that is a part of the tick-borne encephalitis virus complex.The envelope E protein of louping ill virus is the major structural protein that plays an important role in membrane binding and inducing a protective immune response.The aim of the present study was to design multi epitopes vaccine from the envelope E glycoprotein against louping ill virus using immunoinformatic tools that elicited humoral and cellular immunity. Eighteen envelope E protein sequences were retrieved from NCBI and subjected to various immunoinformatics tools from IEDB to assess their conservancy, surface accessibility and antigenicity as promising epitopes against B cells. The binding affinity of the conserved predicted epitopes was analyzed against MHC-I and MHC-II alleles of the T cells. The predicted epitopes were further assessed for their population coverage. For B-cell 25, 18 and 12 epitopes were predicted as linear conserved epitopes, surface accessibility and antigenic respectively. However, nine epitopes overlapped all the B cell prediction tools. Among them three epitopes (205-TAEHLP-210,336-KPCR-339 and 349-SPDV-352) were proposed as B cell epitopes. For T cell, 75 epitopes were found to interact with MHC-I alleles. The epitopes 130-YVYDANKV-138and356-MLITPNPTI-364 were proposed as a peptide vaccine since they interacted with the highest number of MHC-1 alleles.Moreover a total of 195core epitopes were found to interact with MHC-II alleles. The core epitopes 130-YVYDANKV-138, 219-WFNDLALPW-227, 415-VIGEHAWDF-423 and 462-VALAWLGLN-470 interacted with higher number of MHC-II alleles and proposed as vaccine since they demonstrated high affinity to MHC-II alleles.The population coverage epitopes set for MHC-I and MHC-II alleles was 74.69% and 99.98%, respectively. While the epitopes set for all T cell, proposed epitopes was 100%. Nine epitopes were predicted eliciting B and T cells and proposed as vaccine candidates against louping ill virus. However, these proposed epitopes require clinical trials studies to ensure their efficacy as vaccine candidates.