Scientists working on a new tuberculosis (TB) vaccine, effective in humans and cattle, have achieved a major step forward by showing that a TB antigen and vaccine adjuvant can be protected from heat damage.
The technique, which has been developed at the University of Bath, prevents these crucial vaccine components from spoiling outside a fridge.
Researchers say it presents a “big step forward” in helping to develop thermally stable vaccines for livestock by making vaccines that don’t need to be kept in the fridge, making it cheaper for farmers to vaccinate their stock.
How the technique works
Ensilication, a method developed at the University of Bath, “shrink-wraps” vaccine proteins in position using layers of silica that build up into a cage around the molecules – so they don’t unravel when exposed to temperatures that would usually break them down.
See also: 5 ways to improve TB control in the UK
The proteins are held in place until they are ready to be removed from the silica cage and delivered.
The research team from the Departments of Biology & Biochemistry and Chemistry first demonstrated that the TB antigen ag85b and a vaccine fused with the adjuvant protein Sbi are sensitive to breaking down outside of refrigerated temperatures.
They then proved these vaccine components were protected from heat damage when ensilicated and kept on a shelf at room temperature for long periods of time without loss of structure and function.
This is the first time ensilication has been used to improve the thermal stability of proteins in a vaccine setting, after proof-of-principle work using model proteins.
Researchers say ensilication could be used for many different kinds of vaccines.
The study is published in Scientific Reports and was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
First author Ayla Wahid, added: “To make the vaccine as effective as possible, it needs to be thermally stable – or, in other words, not spoil outside of a fridge – which is why we’re really encouraged by these results. Cold-chain storage leads to a lot of wastage and expense that could be avoided by ensilication.”