Synthetic Sugar Based Vaccine Offers Prospects for Broader Protection for Pigs from Strep Suis

A never before used approach to the creation of vaccines in veterinary medicine, developed in partnership with Swine Innovation Porc, offers the prospects of more effective protection for pigs from infections caused by Streptococcus suis.

Strep suis is a bacterial agent that causes different diseases, mostly in nursery pigs, including septicemia with sudden death, meningitis which affects the central nervous system or arthritis impacting the joints.

With funding from Swine Innovation Porc, scientists are exploring novel methods of vaccine development.Dr. Marcelo Gottschalk, the Director of the International Reference Laboratory for Streptococcus suis at the University of Montreal, says two different but complementary approaches have been taken.

Quote-Dr. Marcelo Gottschalk-University of Montreal:

What has been done is an approach to identify a protein which is present in the surface of the bacteria.We have identified one of these proteins, which is called SAO, Streptococcal Antigen-1 and this antigen has been proved to give a certain level of protection against infection, so the idea is to complement that with another kind of candidate.

What we have done is to use synthetic sugars.Strep suis is surrounded by what we call a capsule which is a kind of armor that will envelope the bacteria and protect the bacteria against the immune system.

This capsule is made by sugars, only sugar, and sugars are very bad to induce good antibody production.The host, the pig doesn't see the bacteria when the bacteria enters because it's covered by the sugars.

We've demonstrated in the past that, if we take the sugars from the capsule and we link it to a protein, then the immune system can see the sugar and produce antibodies.

Dr. Gottschalk acknowledges, while linking sugars from the capsule to a protein empowers the immune system to respond, these extracted sugars are too expensive to use as a vaccine so researchers have shifted their focus to the development of synthetic sugars.