Reverse vaccinology and subtractive genomics-based putative vaccine targets identification for Burkholderia pseudomallei Bp1651.

The Burkholderia pseudomallei is a unique bio-threat and causative agent of melioidosis. The B. pseudomallei Bp1651 strain has been isolated from a chronic cystic fibrosis patient. The genome-level DNA sequences information of this strain has recently been published. Unfortunately, there is no commercial vaccine available till date to combat B. pseudomallei infection. The genome-wide prioritization approaches are widely used for the identification of potential therapeutic candidates against pathogens. In the present study, we utilized the recently available annotated genomic information of B. pseudomallei Bp1651 through subtractive genomics and reverse-vaccinology strategies to identify its potential vaccine targets. The analyses identified more than 60 pathogen-specific, human host non-homologous proteins that may prioritize in future studies to investigate therapeutic targets for B. pseudomallei Bp1651. The potential B and T-cells antigenic determinant peptides from these pathogen-specific proteins were cataloged using antigenicity and epitope prediction tools. The analyses unveiled a promising antigenic peptide "FQWEFSLSV" from protein-export membrane protein (SecF) of Bp1651 strain, which was predicted to interact with multiple class I and class II MHC alleles with IC50 value < 100 nM. The molecular docking analysis verified favorable molecular interaction of this lead antigenic peptide with the ligand-binding pocket residues of HLA A*02:06 human host immune cell surface receptor. This peptide is predicted to be a suitable epitope capable to elicit the cell-mediated immune response against the B. pseudomallei pathogen. The putative epitopes and proteins identified in this study may be promising vaccine targets against Bp1651 as well as other pathogenic strains of B. pseudomallei.