We have demonstrated the power of modular building blocks approach of synthetic biology (IMMUNOBRICKS) for the rational design of vaccines
We have designed a new type of vaccine against H. pylori based on chimeric flagellin that combines activation of innate and adaptive immunity in the same molecule
Chimeric flagellins were produced in bacteria, purified and characterized
Engineered flagellins activate TLR5 as opposed to the native H. pylori flagellin
three different implementations of chimeric flagellin vaccines were prepared
chimeric flagellin is localized at the bacterial surface
DNA construct based on chimeric flagellin activates TLR5 on neighboring cells (demonstration of the feasibility of introduction of DNA into epithelial cells to activate underlying dendritic cells)
Antigen-TLR fusions are functional and their localization can be modulated by the selection of transmembrane segment
Various DNA vaccine constructs have been successfully introduced by electroporation intramuscularly or subcutanelously and expression of the fusion protein in the target tissue in vivo was demonstrated
What remains to be done ?
Complete animal studies: demonstrate the profilactic efficiency of our vaccines to prevent colonization, and therapeutic value to eradicate existing infection as well as evaluate effects of vaccinations on histology of gastric mucosa……
Demonstrate the efficiency of bacterial implementation of flagellin-like vaccine on lyophilized bacterial ghosts (more safe and stable vaccine), particularly for oral and mucosal vaccination – prospects for application in third world countries
Analyze different combinations of antigen-TLRs to obtain optimal immune stimulation (TLR synergy)
Repeat all experiments with many controls, in comparison to currently used adjuvants etc
Prospects
Functional vaccine against H. pylori would be definitely welcome
The approach with chimeric flagellins could be used against other flagellated bacteria whose flagellin does not activate innate system (Bartonella, Campylobacter, Borellia...)
Could vaccines based on antigen-TLR fusions be used as tumor vaccines as well?
... ... (ars longa, vita brevis)
Two chimeric recombinant protein vaccines showed intense IgG antibody response in mice and immunized sera also reacted with heat-killed H. pylori antigens implying that they recognize epitopes of H. pylori.
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