Immunization against Pseudomonas aeruginosa using Alg-PLGA nano-vaccine.

OBJECTIVES: Pseudomonas aeruginosa is the bacterium that causes of pulmonary infection among chronically hospitalized patients. Alginate is a common surface antigen of P. aeruginosa with a constant structure that which makes it an appropriate target for vaccines. In this study, P. aeruginosa alginate was conjugated with to PLGA nanoparticles, and its immunogenicity was characterized as a vaccine. MATERIALS AND METHODS: Alginate was isolated from a mucoid strain of P. aeruginosa and conjugated with to PLGA with˝ N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride ˝= ˝EDAC˝ and N-Hydroxysuccinimide (NHS). Chemical characterization of prepared nano-vaccine was performed using FTIR Spectroscopy, Zetasizer, and Atomic Force Microscopy (AFM). The immunogenicity of this nano-vaccine was evaluated through intramuscular injection into BALB/c mice. Four groups of mice were subjected to the injection of alginate-PLGA, and two weeks after the last administration step, opsonophagocytosis assay, IgG detection, challenge, and cytokine determination via ELISA were carried out. RESULTS: Alginate-PLGA conjugation was corroborated by FTIR, Zetasizer, and AFM. The ELISA consequence showed that alginate was prospering in the instigation of the humoral immunity.The immunogenicity enhanced against the alginate-PLGA. Remarkably diminished bacterial titer in the spleen of the immunized mice posterior to challenge with PAO1 strain in comparison with the alginate alone and control groups. CONCLUSION: The bacterial burden in the spleen significantly decreased after the challenge (P<0.05). The opsonic activity was significantly increased in the alginate- PLGA group (P<0.05).

Protective Potential of Conjugated P. aeruginosa LPS -PLGA Nanoparticles in Mice as a Nanovaccine.

BACKGROUND: Pseudomonas aeruginosa has an important role in nosocomial infections. OBJECTIVE: To evaluate biological activity of the detoxified LPS (D-LPS) entrapped into Poly lactic-co-glycolic acid (PLGA) nanoparticles. MATERIALS: LPS was extracted and detoxified from the P. aeruginosa strain PAO1. The D-LPS, conjugated to the PLGA nanoparticles with 1-ethyl-3-dimethyl aminopropyl carbodiimide (EDAC) and N-hydroxy-succinimide (NHS). The connection was evaluated by FTIR (Fourier transform infrared), Zetasizer, and Atomic Force Microscope (AFM). The BALB/c mice injected intramuscularly with the D-LPS-PLGA with two-week intervals and then challenged two weeks after the last immunization. The bioactivity of the induced specific antisera and cytokines responses against D-LPS-PLGA antigen was assessed by ELISA. RESULTS: D-LPS-PLGA conjugation was confirmed by FTIR, Zetasizer, and AFM. The ELISA results showed that D-LPS was successful in the stimulation of the humoral immune response. The immune responses raised against the D-LPS-PLGA, significantly decreased bacterial titer in the spleen of the immunized mice after challenge with PAO1 strain in comparison with the control groups. CONCLUSION: The conjugation of the bacterial LPS to the PLGA nanoparticle increased their functional activity by decrease in bacterial dissemination and increase the killing of opsonized bacteria.

Exotoxin A-PLGA nanoconjugate vaccine against Pseudomonas aeruginosa infection: protectivity in murine model.

Pseudomonas aeruginosa is the major infectious agent of concern for cystic fibrosis (CF) patients. Therefore, it is necessary to develop appropriate strategies for preventing colonization by this bacterium and/or neutralizing virulence factors. In this study, we formulated the encapsulation of exotoxin A into PLGA nanoparticles. The biological activities of the nanovaccine candidate were also characterized. Based on the results, ETA-PLGA can act as a suitable immunogen to stimulate the humoral and cellular immune response. The antibodies raised against ETA-PLGA significantly decreased bacterial titer in the spleens of the immunized mice after challenge with PAO1 strain, compared to the control groups. The encapsulation of PLGA into ETA led to a significantly higher production of INF-γ, TNF-α, IL-4, and IL-17A cytokine responses compared to the ETA group. ETA-PLGA enhanced IgG responses in immunized mice compared to ETA antigen. We concluded that encapsulation of Pseudomonas aeruginosa ETA to PLGA nanoparticles can increase its functional activity by decreasing the bacterial dissemination.