Synthesized Sugar Based Vaccines Allow Pigs’ Immune Systems to Recognize Strep Suis

Farmscape for September 27, 2023

Full Interview 9:00 Listen

Scientists with the Universities of Montreal and Alberta are developing new compounds that will allow the immune system of the pig to recognise and respond to Strep suis. Researchers with the University of Montreal and the University of Alberta, with funding provided by Swine Innovation Pork, have developed a Streptococcus suis vaccine based on the protective sugar coating that envelopes the bacteria and to improve production capability are synthesising that sugar. Dr. Todd Lowary, an organic chemist and professor emeritus with the University of Alberta’s Department of Chemistry, explains his team creates complex sugar molecules by using smaller pieces to make longer chain carbohydrates, much like putting beads on a string, and these molecules are then used in the formulation of vaccines.

Quote-Dr. Todd Lowary-University of Alberta:
All bacteria are coated with a layer of sugar and these sugars do a number of things. It keeps the surface of the bacteria intact.
It also interacts with the immune system of the host and these are good antigens, so they’re good for vaccine development.
If you go about this there are a couple of ways that you can think about developing a vaccine based on this sugar. One is to take the sugar that you isolate from nature and use that. The problem with that approach is that doing that isolation can be quite challenging and it’s very difficult to get large quantities of material.

The other approach, that we have done, is to build this up from the bottom up essentially, using chemistry.
There are advantages in the sense that we can make more amounts of material, we can generally make things in higher purity but the disadvantage is that it’s slower so, at the moment, we’re trying to figure out the best way to make these so that it can be sped up and be more economical. Certainly, the structures of these sugars have been known for a long time so it provides us a roadmap to know what we make. It’s important to have that information before we go in to try to make something.

Dr. Lowary says his lab has created several of these sugars, all of which have been tested and some of which have worked out.
He says the next steps are to streamline the approach and look at different vaccine formulations focussing on improving performance and bringing down the cost of manufacturing.

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