Background:
Outer membrane vesicles (OMVs) release from Gram-negative bacteria
and are interesting alternatives that can replace those vaccines that
contain naturally incorporated bacterial surface antigens,
lipopolysaccharides (LPS) and outer membrane proteins (OMPs).
Nanoparticles can be used to encapsulate vesicles for slow release and
prevent macromolecular degradation.
Objective:
Therefore, encapsulation of OMVs of B. pertussis into sodium alginate nanoparticles was the main aim of the current study.
Methods:
The OMVs of B. pertussis extracted and characterized by particle
sizer, electron microscopy, SDSPAGE and Western blot assays. The
extracted OMVs were encapsulated in sodium alginate nanoparticles
(OMV-NP) using unique gelation process and injected into BALB/c mice.
Immunogenicity indices such as different classes of antibodies and
interleukins related to different T cell lines were evaluated in
immunized mice by ELISA. The respiratory challenge was evaluated in the
groups of mice. The existence of pertussis toxin (PTX), filamentous
haemagglutinin (FHA) and PRN (pertactin) in B. pertussis OMVs was
verified using SDSPAGE and Western blot analysis.
Results:
TEM electron microscopy showed the size of these OMVs to be around
20-80 nm. The OMVs with appropriate quality were encapsulated into
sodium alginate nanoparticles (OMV-NP), and the final size was about 500
nm after encapsulation. Immunity indices were significantly higher in
the OMV-NP receiving group. In challenge tests, the OMV-NP vaccine was
able to show the highest rate of lung clearance compared to the control
groups (OMV and wPV) at the lowest injection dose.
Conclusion:
The results indicate the potential of OMV-NP as a novel vaccine delivery system.