Abstract
Background: Development of vaccine is a promising and cost-effective strategy to prevent emerging multi-drug resistant (MDR) Acinetobacter baumannii infections. The purpose of this study was to prepare a multi-epitope peptide nanovaccine and evaluate its immunogenicity and protective effect in BALB/c mice.Results: The B-cell and T-cell epitopes of Omp22 from A. baumannii were predicted using bioinformatics method and identified by immunological experiments. Three dominant B-cell epitopes and two T-cell epitopes were linked in series and chemically synthesized to generate multi-epitope peptide rOmp22. Then, rOmp22 was encapsulated by chitosan (CS) and polylactic acid glycolic acid (PLGA) to prepare CS-PLGA-rOmp22 nanoparticles (NPs). CS-PLGA-rOmp22 NPs were small (mean size of 272.83 nm) with apparently spherical structural, positively charged (4.39 mV) and exhibited nontoxicity to A549 cells. We achieved a high encapsulation efficiency (54.94%) and a continuous slow release pattern. Compared with non-encapsulated rOmp22, CS-PLGA-rOmp22 induced more rOmp22-specific IgG in serum and IFN-γ in splenocyte supernatant. Vaccination with CS-PLGA-rOmp22 decreased lung injury, suppressed bacterial burdens in the lung and blood, provided potent protection (57.14%-83.3%) against acute lethal intratracheal A. baumannii challenge in BALB/c mice.Conclusions: CS-PLGA-rOmp22 NPs could elicit specific IgG antibody, Th1 cellular immunity and protection against acute lethal intratracheal A. baumannii challenge. Our results indicate this nanovaccine is a disirable candidate to prevent A. baumannii infection.
O6‐1: A multi‐epitope peptide rOmp22 encapsulated in chitosan‐PLGA nanoparticles as vaccine candidate against
Acinetobacter baumannii
infection
