Document Type : Original Article


1 Department of Microbiology, Karaj Branch, Islamic Azad University, Karaj, Iran

2 Department of Microbiology, Zanjan Branch, Islamic Azad University, Zanjan, Iran

3 Biotechnology Research Center, Karaj Branch, Islamic Azad University, Karaj, Iran

4 Pasteur Institute of Iran, Tehran, Iran

5 Department of Rhiopharmacy, Faculty of Pharmacy, Tehran of Medical Science, Tehran, Iran


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.