Designing vaccines for a needle-free future by harnessing the power
of bacterial toxins
Evolution did the hard work...
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Bacteria are known for creating toxins. Some are deadly, others are just plain sneaky.
One family of these sneaky toxins is the AB5 toxins. AB5 toxins are proteins that are really good at penetrating our protective barriers, like skin and the mucosal linings in our respiratory tracts and guts.​
They have a powerful Binding, or B, subunit - a pentamer made up of 5 monomers that self-assemble into a donut-like structure. The B subunit lets them into host cells.​
Once they're there, the Active, or A subunit - which sits in the "hole" of the "donut" - moves on to have some toxic activity. ​
You've probably heard of some of these bacterial "Trojan horses": ​
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Pertussis Toxin, from Bordatella pertussis, disrupts G-protein signalling and contributes to pertussis, or whooping cough.
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Shiga Toxin, from Shigella dysenteriae, inhibits ribosomes and leads to hemolytic uremic syndrome and bloody diarrhea associated with dysentery.
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Diphtheria Toxin, from Corynebacterium diphtheriae, blocks protein synthesis and contributes to diphtheria.
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Perhaps most famously, Cholera Toxin, from Vibrio cholerae, opens up ion channels and causes the watery diarrhea associated with cholera
We're just repurposing it. ​
In our lab, we take cholera toxin, remove the toxic Active subunit and replace it with a protein (antigen) of choice. Once we get the protein biochemistry right, we've created a vaccine.
We harness the power of the Binding subunit and use it as a delivery system to send payloads directly to the immune cells hanging out in the place Cholera Toxin likes to go - skin and mucosal linings in our respiratory tracts and guts. ​
The best part? This vaccine delivery system means no needles.