Vaccination with the immunoglobulin M-degrading enzyme of Streptococcus suis, Ide, leads to protection against a highly virulent serotype 9 strain

Highlights • IdeSsuis vaccination of piglets significantly reduced survival of S. suis cps9 in blood.• IdeSsuis reactive T helper cells producing TNF-α, IL-17A or IFN-ɣ were detectable.• Vaccination resulted in protection against mortality induced by cps9 challenge.