Two peptides derivate from Acinetobacter baumannii outer membrane protein K as vaccine candidates: A comprehensive in silico study

Abstract

Background The lack of appropriate vaccines is an obstacle to the effective management of A. baumannii infections. Peptide vaccines can provide attractive and promising preventive strategies against A. baumannii. Objective Here, specific T cell epitopes of A. baumannii outer membrane protein K (OMPK) were found using comprehensive bioinformatics and detailed molecular docking analysis. Methods Both class-I and class-II T cell epitopes of A. baumannii OMPK were predicted by three tools namely IEDB, SYFPEITHI, and ProPred. The predicted epitopes were shortlisted via several analyses such as prediction scoring, clustering, human similarity exclusion, considering immunogenicity and cytokine production, and removing toxic and/or allergen epitopes. The epitopic peptides with high prediction scores and appropriate properties that contained both class-I and class-II T cell epitopes were selected. Two of these class I/II epitopic peptides were chosen for molecular docking studies and assessing their physicochemical properties as vaccine candidates. Results The results showed many T-cell epitopes of OMPK that could be evaluated for possible immunogenicity. Two of these epitopes (containing both class-I and II epitopes) had high prediction scores, predicted by several tools, attached to several HLAs, and had the best docking score (bind efficiently to their specific HLAs). They had different physicochemical properties and were conserved among Acinetobacter species. Discussion We identified the A. baumannii OMPK high immunogenic class-I and class-II T cell epitopes and introduced two promising high immunogenic peptides as vaccine candidates. It is recommended to do an in vitro/in vivo investigation of these peptides to determine their true efficacy and efficiency.