In-silico identification of b cell epitopes and assessment of chimeric protein derived from surface membrane proteins of Acinetobacter baumannii

Abstract

The rise of multidrug-resistant Acinetobacter baumannii has intensified the need for alternative therapeutic approaches, such as epitope-based vaccines. Multi-epitope chimeric vaccines designed through immunoinformatic provide a promising strategy by targeting conserved antigenic regions with high immunogenic potential. This study employed reverse vaccinology and immunoinformatic tools to design and evaluate six multi-epitope chimeric protein constructs targeting A. baumannii. B-cell epitopes were predicted and screened for physiological properties. Chimeric constructs were assembled using different linker strategies and assessed for physicochemical properties, solubility, stability and immunogenic potential. All six constructs exhibited high antigenicity (VaxiJen scores > 0.7), were predicted to be non-allergenic, and hydrophilic in nature, favouring solubility. However, only Chimera 3 and Chimera 4, both designed with rigid linkers, demonstrated structural stability. Chimera 3 was identified as the most promising candidate based on its high antigenicity (1.72), solubility, half-life (>10 hours), stability (instability index < 40) and non-allergenicity. Chimera 3 represents a robust vaccine candidate with favourable immunological and physicochemical properties. The study highlights the critical role of rigid linkers in maintaining chimera stability and supports further in vitro and in vivo validation of Chimera 3 as a potential subunit vaccine against A. baumannii.