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Volume 51, Number 3, June 2018

Immunization with outer membrane proteins (OprF and OprI) and flagellin B protects mice from pulmonary infection with mucoid and nonmucoid Pseudomonas aeruginosa 


Ramadan Hassan, Wael El-Naggar, Abeer M. Abd El-Aziz, Mona Shaaban, Hany I. Kenawy, Youssif M. Ali


 

Corresponding author:

Affiliations
Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
Correspondence
Corresponding author. Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt. 



 

Background and purpose: 

Pseudomonas aeruginosa is a Gram-negative opportunistic bacterium, which considered as a common cause of nosocomial infection and life-threatening complications in immunocompromized and cystic fibrosis patients. Here, we evaluate the protective effect of recombinant vaccines composed of outer membrane proteins OprF and OprI alone or in combination with flagellin B against mucoid and nonmucoid pseudomonas infection. 



 

Methods:

BALB/C mice were immunized subcutaneous using OprF and OprI with or without flagellin B and antibody titers were determined. Serum bactericidal and opsonophagocytosis activities of immunized and control sera were estimated against mucoid and nonmucoid pseudomonas strains. Lung tissue sections from immunized and nonimmunized mice were analyzed and the levels of peripheral neutrophils infiltration into the lung and tissue inflammation were scored. 



 

Results:

Subcutaneous immunization using OprF and OprI with or without flagellin B elicited higher antibody titers against OprF, OprI, and flagellin B. The produced antibodies successfully opsonized both mucoid and nonmucoid strains with subsequent activation of the terminal pathway of complement that enhances killing of nonmucoid strains via complement-mediated lysis. Furthermore, opsonized mucoid and nonmucoid strains showed enhanced opsonophagocytosis via human peripheral neutrophils, a mechanism that kills P. aeruginosa when complement mediated lysis is not effective especially with mucoid strains. Immunized mice also showed a significant prolonged survival time, lower bacteremia, and reduced lung damage when compared with control nonimmunized mice 



 

Conclusion:

Our data showed that mice immunized with OprF/OprI or OprF/OprI and flagellin B are significantly protected from infection caused by mucoid and nonmucoid strains of P. aeruginosa. 



 

Key words:

flagellin B, mucoid, nonmucoid, outer membrane proteins, Pseudomonas aeruginosa