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Molecular determinants of Yersinia pathogenesis
1Microbial Pathogenesis Unit, International Institute of Cellular and Molecular Pathology (ICP), Brussels, Belgium.
Microbiologia (Madrid, Spain)
|June 1, 1996
Summary
Pathogenic Yersinia species resist host immunity using a virulence plasmid (pYV) encoding Yops. These Yop proteins are secreted via a type III secretion system and directly enter host cells, aiding bacterial pathogenesis.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- The genus Yersinia comprises three pathogenic species: Yersinia pestis, Y. pseudotuberculosis, and Y. enterocolitica.
- These species share tropism for lymphoid tissues and resist host immune responses.
- Virulence is largely mediated by a conserved 70-kb virulence plasmid (pYV).
Purpose of the Study:
- To elucidate the genetic determinants of Yersinia virulence, focusing on the pYV plasmid.
- To describe the role of Yop proteins and their secretion system in pathogenesis.
- To identify additional virulence factors encoded on the Y. enterocolitica chromosome.
Main Methods:
- Analysis of genes encoded by the pYV virulence plasmid.
- Characterization of Yop proteins, including their secretion and internalization mechanisms.
- Identification of chromosomal virulence factors in Y. enterocolitica, such as enterotoxin (Yst), fibrillae (Myf), and invasin (Inv).
Main Results:
- The pYV plasmid encodes key virulence factors: YlpA, YadA, and at least 11 Yop proteins.
- A type III secretion system, encoded by pYV, is responsible for Yop secretion.
- Yop proteins are directly translocated into the host cell cytosol, a novel pathogenic mechanism.
Conclusions:
- The pYV plasmid is crucial for Yersinia's ability to resist host immunity and establish infection.
- Type III secretion of Yops represents a significant virulence strategy in Yersinia pathogenesis.
- Chromosomal factors like Yst, Myf, and Inv further contribute to the virulence of Y. enterocolitica.