Recombinant outer membrane vesicles to augment antigen-specific live vaccine responses

Area of Science:

• Microbiology
• Immunology
• Vaccine Development

Background:

• Outer membrane vesicles (OMVs) from Gram-negative bacteria are explored for affordable vaccine development.
• A convenient system for generating recombinant OMVs is needed to maximize their potential.

Purpose of the Study:

• To design and validate a versatile system for producing recombinant OMVs using an engineered autotransporter.
• To assess the efficacy of these recombinant OMVs in a prime-boost vaccination model.

Main Methods:

• Engineered an autotransporter system based on AIDA (adhesin involved in diffuse adhesion) from Escherichia coli.
• Expressed two Leishmania vaccine antigens as fusion proteins with the AIDA transporter domain.
• Administered single subcutaneous injections of recombinant OMVs to mice previously primed with live recombinant Salmonella vaccines.

Main Results:

• Recombinant OMVs significantly boosted vaccine antigen-specific antibody responses in mice by 6-40 fold.
• The vaccination strategy expanded only the vaccine antigen-specific antibody response.
• Demonstrated the potential of this system for prime-boost vaccination.

Conclusions:

• The developed autotransporter-based system provides a versatile method for generating recombinant OMVs.
• This approach is highly effective for enhancing specific antibody responses in prime-boost vaccination strategies.
• Recombinant OMVs hold significant potential for developing next-generation vaccines.