Skip to main content
SLU publication database (SLUpub)
Research article - Peer-reviewed, 2006

IdeE, an IgG-endopeptidase of Streptococcus equi ssp equi

Lannergard J, Guss B


Streptococcus equi ssp. equi is the causative agent of strangles, a highly contagious and serious disease in the upper respiratory tract of horses. The present study describes the characterization of IdeE, a homolog of the secreted IgG-specific protease IdeS/Mac of Streptococcus pyogenes. The activity of IdeE is compared with the activity of IdeZ, the corresponding enzyme of the closely related S. equi ssp. zooepidemicus. A study of the proteolytic activity of recombinant IdeE and IdeZ on IgG from a selection of mammals shows that only antibodies containing the substrate site of IdeS/Mac are cleaved, indicating that the specificities of these enzymes are similar. Interestingly, IgG from horse is less effectively cleaved than IgG from e.g. dog or humans, as the dominating IgG isotype in horse sera (IgG4) lacks a distinct substrate site for IdeE/IdeZ. IgG-degradation is observed when S. equi ssp. equi is grown in the presence of horse serum, but not when grown with purified IgG. As the fraction of degraded IgG contains IgG4, the observed activity might be due to the expression of an unknown enzyme rather than IdeE. In a similar assay, no proteolysis of IgG was detected in the growth media of S. equi ssp. zooepidemicus

Published in

FEMS Microbiology Letters
2006, Volume: 262, number: 2, pages: 230-235

      SLU Authors

    • UKÄ Subject classification

      Animal and Dairy Science
      Veterinary Science

      Publication Identifiers


      Permanent link to this page (URI)