Journal article
Rhodococcus equi Secreted Antigens Are Immunogenic and Stimulate a Type 1 Recall Response in the Lungs of Horses Immune to R. equi Infection
Infection and immunity, Vol.71(11), pp.6329-6337
11/2003
Handle:
https://hdl.handle.net/2376/109574
PMCID: PMC219552
PMID: 14573652
Abstract
Rhodococcus equi
is an opportunistic pathogen in immunocompromised humans and an important primary pathogen in young horses. Although
R. equi
infection can produce life-threatening pyogranulomatous pneumonia, most foals develop a protective immune response that lasts throughout life. The antigen targets of this protective response are currently unknown; however,
Mycobacterium tuberculosis
is a closely related intracellular pathogen and provides a model system. Based on previous studies of
M. tuberculosis
protective antigens released into culture filtrate supernatant (CFS), a bacterial growth system was developed for obtaining
R. equi
CFS antigens. Potential immunogens for prevention of equine rhodococcal pneumonia were identified by using immunoblots. The 48-h CFS contained five virulence-associated protein bands that migrated between 12 and 24 kDa and were recognized by sera from
R. equi
-infected foals and immune adult horses. Notably, the CFS contained the previously characterized proteins VapC, VapD, and VapE, which are encoded by genes on the
R. equi
virulence plasmid.
R. equi
CFS was also examined for the ability to stimulate a type 1-like memory response in immune horses. Three adult horses were challenged with virulent
R. equi
, and cells from the bronchoalveolar lavage fluid were recovered before and 1 week after challenge. In vitro stimulation of pulmonary T-lymphocytes with
R. equi
CFS resulted in significant proliferation and a significant increase in gamma interferon mRNA expression 1 week after challenge. These results were consistent with a memory effector response in immune adult horses and provide evidence that
R. equi
CFS proteins are antigen targets in the immunoprotective response against
R. equi
infection.
Metrics
6 Record Views
Details
- Title
- Rhodococcus equi Secreted Antigens Are Immunogenic and Stimulate a Type 1 Recall Response in the Lungs of Horses Immune to R. equi Infection
- Creators
- Andrea K Kohler - Department of Veterinary Microbiology and PathologyDiana M Stone - Department of Veterinary Microbiology and PathologyMelissa T Hines - Department of Veterinary Microbiology and PathologyBarbara A Byrne - Department of Veterinary Microbiology and PathologyDebra C Alperin - Department of Veterinary Microbiology and PathologyLinda K Norton - Department of Veterinary Microbiology and PathologyStephen A Hines - Department of Veterinary Microbiology and Pathology
- Publication Details
- Infection and immunity, Vol.71(11), pp.6329-6337
- Academic Unit
- Veterinary Medicine, College of; Veterinary Microbiology and Pathology, Department of
- Publisher
- American Society for Microbiology
- Identifiers
- 99900547241301842
- Language
- English
- Resource Type
- Journal article