In silico Analysis of Acinetobacter baumannii Outer Membrane Protein BamA as a Potential Immunogen

Abstract: A. baumannii is an emerging nosocomial pathogen associated with health care units. Its resistance to various antibiotics gives rise to the need of vaccine development against it. Outer membrane proteins are well described vaccine candidates. The outer membrane assembly complex protein of A. baumannii, known as BamA, is an essential component of β-Barrel Assembly Machine (BAM). Vaxign analysis showed that BamA has no trans-membrane helix, adhesion probability is 0.54, no similarity to human & mouse proteome and is highly conserved (>99%) in 114 strains of A. baumannii as well as in other virulent species of Acinetobacter (78 to 94%). Multiple sequence alignment (Multalin) of BamA protein sequences from different species of Acinetobacter revealed the conserved regions and led to the identification of T cell epitopes. A number of (15) common T cell epitopes in 8 species of Acinetobacter, antigenicity (predicted score of 0.682) and outer membrane localization predict that BamA offers appropriate epitopes for immunity development against all species of Acinetobacter. Further, docking of MHC class I binding epitopes to HLA*B4405 allele and docking of epitope-HLA*B4405 complex to DM1-T cell receptor showed stable binding with low energies