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Association of Streptococcus equi with equine monocytes
Catherine Mérant1, Abhineet Sheoran, John F Timoney
1Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
Veterinary Immunology and Immunopathology
|July 15, 2011
Summary
Equine strangles bacteria, Streptococcus equi, are killed by blood monocytes, not just neutrophils. This suggests monocytes and macrophages clear infections and transport bacteria to lymph nodes.
Area of Science:
- Veterinary Immunology
- Equine Infectious Diseases
- Bacteriology
Background:
- Streptococcus equi (Se) causes equine strangles and resists neutrophil phagocytosis, typically considered extracellular.
- The clearance of Se from tonsillar tissues during convalescence remains poorly understood.
Purpose of the Study:
- To investigate the role of equine blood monocytes in the clearance of Streptococcus equi.
- To explore the mechanisms underlying the elimination of Se during the acute phase of equine strangles.
Main Methods:
- Utilized an opsono-bactericidal assay to assess Se killing by monocytes.
- Employed cytometry and confocal microscopy to visualize Se internalization by monocytes.
Main Results:
- Demonstrated that equine blood monocytes effectively interiorize and kill Streptococcus equi.
- Provided evidence for monocyte involvement in the clearance of Se.
Conclusions:
- Equine monocytes play a crucial role in eliminating Streptococcus equi, challenging its classification solely as an extracellular pathogen.
- Monocytes and macrophages may mediate adaptive immune clearance and facilitate bacterial transport from tonsils to lymph nodes in horses.
