Horse-human link provides vaccine hope

Friday July 15th, 2011

Genetic studies of an organism that infects both humans and horses could open the way to new vaccines, researchers said today.

Animal and human researchers have been comparing findings on the streptococcus bacteria - and found clues for future research.

The strains of streptococcus pyogenes and its equine counterpart streptococcus equi share “clever tricks”, says Dr Andrew Waller from the Animal Health Trust, of Suffolk, UK, who conducted a review on S. equi.

Streptococcus pyogenes is responsible for tonsillitis, scarlet fever and toxic shock syndrome in humans, while s.equi causes the disease strangles.

"These strains share clever tricks, like secreting 'superantigens' that allow the microbes to send the immune system into turmoil yet avoid detection themselves," he explains.

Another shared trait is the production of SlaA, a toxin related to the venom of the Australian brown snake that is associated with serious disease in humans.

"The resemblances between the two strains prove it is unrealistic to study human and animal pathogens in isolation, in our quest to understand and fight them," adds Dr Waller, who collaborated with Professor John Timoney from the University of Kentucky, USA.

Writing in the Journal of Medical Microbiology, Dr Waller said the genetic similarities could lead to novel vaccines for both man and horses.

"One vaccine against strangles that is currently being trialled uses antigenic components that share similarity with their S. pyogenes counterparts to stimulate immunity," said Dr Waller.

"If this approach can protect horses against S. equi, it is feasible that a similar cocktail of S. pyogenes antigens may be the basis for an effective vaccine for humans, which is an exciting prospect."

Journal of Medical Microbiology July 15 2011 doi: 10.1099/jmm.0.028233

Tags: General Health | Genetics | North America | UK News

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