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Discussion on Research Study: Why is Strangles so Hard on Horses?
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Moderator:
DrO
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Posted on Thursday, May 8, 2008 - 10:05 am:
Why is Strangles, a strep infection of the upper airway, such a serious disease with severe symptoms in horses. Here a study has found one of the possible reasons. The organism releases a chemical which greatly attenuates the ability of the horses WBC's to fight the disease. Specifically the Strangles organism prevents phagocytosis by the neutrophils. Hopefully such information will lead to better treatment and vaccinations.
DrO
Vet Immunol Immunopathol. 2008 Mar 15;122(1-2):76-82.
IdeE reduces the bactericidal activity of equine neutrophils for Streptococcus equi.
Timoney JF, Yang J, Liu J, Merant C.
Department of Veterinary Science, University of Kentucky, Lexington, KY 40546-0099, USA. jtimoney@email.uky.edu
Streptococcus equi (S. Sequi) causes equine strangles, a highly contagious and widespread purulent lymphadenitis of the head and neck. Highly resistant to phagocytosis, it produces long extracellular chains in affected lymph nodes. In a screen of clones reactive with convalescent serum from a gene library of S. Sequi CF32 we identified IdeE, an IgG-endopeptidase and homologue of the leukocyte receptor Mac-1 (CD11b). IdeE is expressed during S. Sequi infection eliciting both serum and mucosal antibody responses which persisted at significant levels in serum for over 200 days. Release from S. Sequi into culture medium was detected during the exponential phase of growth. The closely related Streptococcus zooepidemicus appeared to store the protein but not to release it. Antiphagocytic activity for equine neutrophils was dose-dependent and neutralized by IdeE-specific antiserum. Biotinylated IdeE bound weakly to about 77% of purified equine neutrophils and strongly to the remainder.
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Member:
imogen
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Posted on Friday, May 9, 2008 - 8:48 am:
Wow! That should get the interest of a few animal health companies...
Imogen
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