Immunoinformatic Prediction of B-Cell and MHC-Associated Epitopes from Echinococcus granulosus Adenylate Kinase 1 (ADK1) as a Candidate Vaccine Antigen

Abstract

The present study focused on Echinococcus granulosus adenylate kinase 1 (ADK1) to characterize its main biochemical features and predict potential B- and T-cell epitopes that may support its evaluation as a candidate for multi-epitope vaccine development. Multiple online servers were used for in silico analysis of the EgADK1 protein. The analysis predicted ADK1 as a cytoplasmic protein of about 22 kDa, with appropriate hydrophilicity (GRAVY: –0.286), stability (instability index: 17.48), and broad thermotolerance (aliphatic index: 93.45) in silico. It was also predicted to carry 15 phosphorylation and 2 O-glycosylation sites as post-translational modifications. Secondary structure modeling suggested that helices and random coils dominate its composition. A three-dimensional structure was built using the Robetta server with a high confidence score (0.88) and validated by Ramachandran plots and ERRAT. Altogether, 4 final B-cell epitopes (EVQSGSPRGKELQAI, KHYTQKGK, KRGETSGRADDNEATI, ADDNEATIVQ), and several murine and human MHC-restricted epitopes were identified. Human epitopes, particularly HTLs, were predicted to possess moderately high population coverage worldwide. The predicted biochemical stability, strong antigenicity, and high population coverage of EgADK1 epitopes highlight its potential as a conserved multi-stage vaccine candidate, supporting previous findings that targeting essential metabolic proteins may complement existing CE vaccine strategies. Overall, the findings indicate that predicted immunogenic epitopes of ADK1 are promising starting points for experimental testing in vaccine research against CE. However, experimental studies remain essential to test the protein directly, either alone or in combination with other candidate antigens.