Whole-cell vaccine candidates induce a protective response against virulent Acinetobacter baumannii

Abstract

Acinetobacter baumannii causes multi-system diseases in both nosocomial settings and a pre-disposed general population. The bacterium is not only desiccation-resistant but also notoriously resistant to multiple antibiotics and drugs of last resort including carbapenem, colistin, and sulbactam. The World Health Organization has categorized carbapenem-resistant A. baumannii at the top of its critical pathogen list in a bid to direct urgent countermeasure development. Several early-stage vaccines have shown a range of efficacies in healthy mice, but no vaccine candidates have advanced into clinical trials. Herein, we report our findings that both an ionizing γ-radiation-inactivated and a non-ionizing ultraviolet C-inactivated whole-cell vaccine candidate protects neutropenic mice from pulmonary challenge with virulent AB5075, a particularly pathogenic isolate. In addition, we demonstrate that a humoral response is sufficient for this protection via the passive immunization of neutropenic mice.

Influenza Virus Inactivated by Heavy Ion Beam Irradiation Stimulates Antigen-Specific Immune Responses

“…Nonetheless, high doses of ionizing radiation (γ-ray) can alter surface structures, resulting in reduced vaccine efficacy [ 22 ]. In the case of ionizing radiation, radioprotectors such as a reconstituted Mn-decapeptide (MDP) antioxidant complex have been implemented to limit the damage [ 35 , 36 ]. Other alternatives to γ-irradiation rely on low- [ 37 , 38 ] and high-energy [ 39 ] electrons.…”