Evaluation of PLGA nanoparticles containing outer membrane proteins of Acinetobacter baumannii bacterium in stimulating the immune system in mice
Afshin Gholizadeh1, Reza Shapoury2, Parviz Pakzad1, Mehdi Mahdavi3, Hossein Danafar4
1 Department of Microbiology, Faculty of Sciences, North Tehran Branch, Islamic Azad University, Tehran, I.R. Iran
2 Department of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan, I.R. Iran
3 Advanced Therapy Medicinal Product (ATMP) Department, Breast Cancer Research Center, Motamed Cancer Institute, Academic Center for Education, Culture and Research (ACECR); Recombinant Vaccine Research Center, Tehran University of Medical Science, Tehran, I.R. Iran
4 Department of Medical Chemistry, Zanjan University of Medical Sciences, Zanjan, I.R. Iran
Department of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan
Source of Support: None, Conflict of Interest: None
Background and purpose: Acinetobacter baumannii (A. baumannii) is known as a pathogen with antibiotic resistance, causing respiratory infections. PLGA has been approved for use in vaccines as well as drug delivery. This study was performed to evaluate PLGA nanoparticles containing the outer membrane proteins (OMPs) of A. baumannii in stimulating the mice’s immune system and improving pneumonia.
Experimental approach: Double emulsion solvent evaporation technique was used. The properties of the obtained nanospheres were determined using a zetasizer, FTIR, and AFM devices. Nanoparticles were administered to mice BALB/c by applying the intramuscular route. ELISA was used to measure the amounts of immunoglobulins produced; also, an opsonophagocytic killing assay was used to measure the effectiveness of immunoglobulins. Immunized mice were then challenged with live A. baumannii through the lungs; their internal organs were also removed for bacteriological studies.
Findings/Results: The prepared particles were 550 nm in diameter with a negative surface charge. The production of the OMPs specific IgG was much higher in the group receiving nanoparticles containing antigen as compared to those getting pure antigen. The immunoglobulins produced against nanoparticles were superior to those developed against pure antigens. Mice that received the new nanovaccine were more resistant to pneumonia caused by this bacterium than those that received pure antigen.
Conclusion and implication: Overall, it can be said that PLGA nanoparticles could deliver their internal antigens (OMPs) well to the immune system of mice and stimulate humoral immunity in these animals, thus protecting them against pneumonia caused by A. baumannii.