Immune responses to epitopes inserted in Salmonella flagellin

Area of Science:

• Molecular Biology
• Vaccinology
• Immunology

Background:

• Plasmid pLS408 contains the Salmonella flagellin gene (fliC) with a modified antigenically-determinant region.
• Engineering chimeric flagellins allows for the display of foreign epitopes on bacterial flagella.

Purpose of the Study:

• To investigate the production of chimeric flagellins with foreign peptide epitopes inserted into Salmonella flagellin.
• To assess the immunogenicity and potential protective effects of these chimeric flagellins in a live vaccine system.

Main Methods:

• Insertion of synthetic oligonucleotides encoding foreign peptide epitopes into the EcoRV site of pLS408.
• Expression of chimeric flagellins in a flagellin-deficient Salmonella dublin live-vaccine strain.
• Immunization of mice with the engineered live vaccine or semi-purified chimeric flagella/flagellin.
• Analysis of antibody production and protective immunity against pathogen challenge.

Main Results:

• Chimeric flagellins were produced, displaying foreign epitopes on the surface of functional flagella.
• Administration of the live vaccine induced antibodies specific for the foreign epitopes.
• Partial protection against Streptococcus and influenza A virus challenge was observed following immunization.

Conclusions:

• Chimeric flagellins can be successfully engineered to display foreign epitopes, serving as a platform for vaccine development.
• The live Salmonella vaccine system effectively presents these chimeric antigens, eliciting humoral immune responses.
• Further research is needed to understand factors influencing functional flagella production and cellular immune responses.