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Potential of protein OprF of Pseudomonas in bivalent vaccines
1Department of Microbiology and Immunology, University of British Columbia, Vancouver.
Abstract:
Outer membrane protein OprF is the major outer membrane of Pseudomonas aeruginosa, and has been expressed to a similar high level in Escherichia coli from the cloned gene. It contains conserved surface epitopes, and antibodies against these epitopes can protect mice from P. aeruginosa infections. To develop the oprF gene as a carrier for foreign epitopes, linker insertion mutagenesis has been performed to introduce 12 nucleotide inserts marked by a unique PstI site. Nine such sites can accept and express a foreign epitope within the surface loop regions of OprF on the surface of E. coli. The antigenicity at a given insertion site, and the influence of the length of a model repeating malarial epitope on antigenicity, have been shown to be site-specific and apparently dependent on the nature of the surrounding amino acids at the insertion site. Immunization of mice with OprF containing a highly antigenic inserted epitope led to an epitope-specific antibody response. These data suggest that OprF has potential for use as a carrier for foreign epitopes.
Insights
Outer membrane protein OprF from Pseudomonas aeruginosa can be engineered in Escherichia coli to display foreign epitopes. This OprF-based carrier elicits epitope-specific antibodies, showing potential for vaccine development.
Area of Science:
- Microbiology
- Immunology
- Biotechnology
Background:
- Outer membrane protein OprF is a major component of Pseudomonas aeruginosa.
- OprF possesses conserved surface epitopes that elicit protective antibodies.
- Developing OprF as a carrier for foreign antigens is a strategy for novel vaccine development.
Purpose of the Study:
- To engineer the OprF protein as a carrier for foreign epitopes.
- To investigate the feasibility of expressing foreign epitopes on the surface of Escherichia coli using OprF.
- To assess the antigenicity and immunogenicity of OprF displaying foreign epitopes.
Main Methods:
- OprF gene was cloned and expressed in Escherichia coli.
- Linker insertion mutagenesis was used to introduce PstI sites for foreign epitope insertion.
- A model malarial epitope was inserted at various sites within OprF.
- Immunization of mice with engineered OprF and analysis of antibody responses.
Main Results:
- Nine insertion sites within OprF were identified that can express foreign epitopes on the E. coli surface.
- Antigenicity of inserted epitopes was site-specific and influenced by surrounding amino acids.
- The length of the inserted epitope affected its antigenicity.
- Immunization with OprF-displayed epitopes induced epitope-specific antibodies.
Conclusions:
- Pseudomonas aeruginosa outer membrane protein OprF can be genetically modified to serve as a carrier for foreign epitopes.
- Engineered OprF expressed on E. coli surface demonstrates potential for displaying immunogenic epitopes.
- OprF-based carriers show promise for developing new vaccines against infectious diseases.