Journal article
Clearance of Virulent but Not Avirulent Rhodococcus equi from the Lungs of Adult Horses Is Associated with Intracytoplasmic Gamma Interferon Production by CD4+ and CD8+ T Lymphocytes
Clinical and diagnostic laboratory immunology, Vol.10(2), pp.208-215
03/2003
Handle:
https://hdl.handle.net/2376/107961
PMCID: PMC150533
PMID: 12626444
Abstract
Rhodococcus equi
is a gram-positive bacterium that infects alveolar macrophages and causes rhodococcal pneumonia in horses and humans. The virulence plasmid of
R. equi
appears to be required for both pathogenicity in the horse and the induction of protective immunity. An understanding of the mechanisms by which virulent
R. equi
circumvents protective host responses and by which bacteria are ultimately cleared is important for development of an effective vaccine. Six adult horses were challenged with either virulent
R. equi
or an avirulent, plasmid-cured derivative. By using a flow cytometric method for intracytoplasmic detection of gamma interferon (IFN-γ) in equine bronchoalveolar lavage fluid (BALF) cells, clearance of the virulent strain was shown to be associated with increased numbers of pulmonary CD4
+
and CD8
+
T lymphocytes producing IFN-γ. There was no change in IFN-γ-positive cells in peripheral blood, suggesting that a type 1 recall response at the site of challenge was protective. The plasmid-cured strain of
R. equi
was cleared in horses without a significant increase in IFN-γ-producing T lymphocytes in BALF. In contrast to these data, a previous report in foals suggested an immunomodulating role for
R. equi
virulence plasmid-encoded products in downregulating IFN-γ expression by equine CD4
+
T lymphocytes. Intracytoplasmic detection of IFN-γ provides a method to better determine whether modulation of macrophage-activating cytokines by virulent strains occurs uniquely in neonates and contributes to their susceptibility to rhodococcal pneumonia.
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Details
- Title
- Clearance of Virulent but Not Avirulent Rhodococcus equi from the Lungs of Adult Horses Is Associated with Intracytoplasmic Gamma Interferon Production by CD4+ and CD8+ T Lymphocytes
- Creators
- Stephen A Hines - Department of Veterinary Microbiology and PathologyDiana M Stone - Department of Veterinary Microbiology and PathologyMelissa T Hines - Department of Veterinary Microbiology and PathologyDebby C Alperin - Department of Veterinary Microbiology and PathologyDonald P Knowles - Department of Veterinary Microbiology and PathologyLinda K Norton - Department of Veterinary Microbiology and PathologyMary J Hamilton - Department of Veterinary Microbiology and PathologyWilliam C Davis - Department of Veterinary Microbiology and PathologyTravis C McGuire - Department of Veterinary Microbiology and Pathology
- Publication Details
- Clinical and diagnostic laboratory immunology, Vol.10(2), pp.208-215
- Academic Unit
- Veterinary Medicine, College of; Veterinary Microbiology and Pathology, Department of
- Publisher
- American Society for Microbiology
- Identifiers
- 99900547170401842
- Language
- English
- Resource Type
- Journal article