Journal article
Antibodies to a Surface-Exposed, N-terminal Domain of Aggregation Substance Are Not Protective in the Rabbit Model of Enterococcus faecalis Infective Endocarditis
Infection and immunity, Vol.69(5), pp.3305-3314
05/2001
DOI: 10.1128/IAI.69.5.3305-3314.2001
PMCID: PMC98289
PMID: 11292753
Abstract
The aggregation substance (AS) surface protein from
Enterococcus faecalis
has been implicated as an important virulence factor for the development of infective endocarditis. To evaluate the role of antibodies specific for Asc10 (the AS protein from the conjugative plasmid pCF10) in protective immunity to infective endocarditis, an N-terminal region of Asc10 lacking the signal peptide and predicted to be surface exposed (amino acids 44 to 331; AS
44–331
) was cloned with a C-terminal histidine tag translational fusion and expressed from
Escherichia coli
. N-terminal amino acid sequencing of the purified protein revealed the correct sequence, and rabbit polyclonal antisera raised against AS
44–331
reacted specifically to Asc10 expressed from
E. faecalis
OG1SSp, but not to other proteins as judged by Western blot analysis. Using these antisera, flow cytometry analysis demonstrated that antibodies to AS
44–331
bound to a surface-exposed region of Asc10. Furthermore, antibodies specific for AS
44–331
were opsonic for
E. faecalis
expressing Asc10 in vitro but not for cells that did not express Asc10. New Zealand White rabbits immunized with AS
44–331
were challenged intravenously with
E. faecalis
cells constitutively expressing Asc10 in the rabbit model of experimental endocarditis. Highly immune animals did not show significant differences in clearance of organisms from the blood or spleen or in formation of vegetations on the aortic valve, in comparison with nonimmune animals. Although in vivo expression of Asc10 was demonstrated by immunohistochemistry, these experiments provide evidence that immunity to Asc10 does not play a role in protection from experimental infective endocarditis due to
E. faecalis
and may have important implications for the development of immunological approaches to combat enterococcal endocarditis.
Details
- Title: Subtitle
- Antibodies to a Surface-Exposed, N-terminal Domain of Aggregation Substance Are Not Protective in the Rabbit Model of Enterococcus faecalis Infective Endocarditis
- Creators
- John K McCormick - Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455Helmut Hirt - Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455Christopher M Waters - Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455Timothy J Tripp - Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455Gary M Dunny - Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455Patrick M Schlievert - Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455
- Resource Type
- Journal article
- Publication Details
- Infection and immunity, Vol.69(5), pp.3305-3314
- DOI
- 10.1128/IAI.69.5.3305-3314.2001
- PMID
- 11292753
- PMCID
- PMC98289
- NLM abbreviation
- Infect Immun
- ISSN
- 0019-9567
- eISSN
- 1098-5522
- Publisher
- American Society for Microbiology
- Language
- English
- Date published
- 05/2001
- Academic Unit
- Microbiology and Immunology; Internal Medicine
- Record Identifier
- 9984001211402771
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