Journal article
Virulence Plasmid of Rhodococcus equi Contains Inducible Gene Family Encoding Secreted Proteins
Infection and immunity, Vol.69(2), pp.650-656
02/2001
Handle:
https://hdl.handle.net/2376/113973
PMCID: PMC97935
PMID: 11159951
Abstract
Rhodococcus equi
causes severe pyogranulomatous pneumonia in foals. This facultative intracellular pathogen produces similar lesions in immunocompromised humans, particularly in AIDS patients. Virulent strains of
R. equi
bear a large plasmid that is required for intracellular survival within macrophages and for virulence in foals and mice. Only two plasmid-encoded proteins have been described previously; a 15- to 17-kDa surface protein designated virulence-associated protein A (VapA) and an antigenically related 20-kDa protein (herein designated VapB). These two proteins are not expressed by the same
R. equi
isolate. We describe here the substantial similarity between VapA and VapB. Moreover, we identify three additional genes carried on the virulence plasmid,
vapC
, -
D
, and -
E
, that are tandemly arranged downstream of
vapA
. These new genes are members of a gene family and encode proteins that are approximately 50% homologous to VapA, VapB, and each other.
vapC
, -
D
, and -
E
are found only in
R. equi
strains that express VapA and are highly conserved in VapA-positive isolates from both horses and humans. VapC, -D, and -E are secreted proteins coordinately regulated by temperature with VapA; the proteins are expressed when
R. equi
is cultured at 37°C but not at 30°C, a finding that is compatible with a role in virulence. As secreted proteins, VapC, -D, and -E may represent targets for the prevention of rhodococcal pneumonia. An immunologic study using VapA-specific antibodies and recombinant Vap proteins revealed no evidence of cross-reactivity despite extensive sequence similarity over the carboxy terminus of all four proteins.
Metrics
8 Record Views
Details
- Title
- Virulence Plasmid of Rhodococcus equi Contains Inducible Gene Family Encoding Secreted Proteins
- Creators
- Barbara A Byrne - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040John F Prescott - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Guy H Palmer - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Shinji Takai - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Vivian M Nicholson - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Debra C Alperin - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040Stephen A Hines - Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040
- Publication Details
- Infection and immunity, Vol.69(2), pp.650-656
- Academic Unit
- Paul G. Allen School for Global Animal Health; Veterinary Medicine, College of
- Publisher
- American Society for Microbiology
- Identifiers
- 99900547463301842
- Language
- English
- Resource Type
- Journal article