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The cytotoxic protein YopE of Yersinia obstructs the primary host defence
R Rosqvist1, A Forsberg, M Rimpiläinen
1Department of Cell and Microbiology, Swedish Defence Research Establishment, Umeå.
Abstract:
It has previously been shown that the plasmid-encoded YopE protein of Yersinia pseudotuberculosis is a virulence determinant. In this study, HeLa cells, macrophages and mice were used as different model systems to determine the actual role of YopE in the virulence process. The YopE protein mediates a cytotoxic response on a confluent layer of HeLa cells. A prerequisite of this activity is that the pathogen binds to the cell surface. YopE also induces a cytotoxic response on mouse macrophages where it influences the ability of the pathogen to resist phagocytosis. Bacterial mutants defective in their ability to express YopE are avirulent after oral or intraperitoneal infection but virulent following intravenous injection. On the basis of these results, we propose a role for YopE in the virulence process of Yersinia.
Insights
The Yersinia pseudotuberculosis YopE protein is crucial for virulence, causing cell damage and affecting bacterial resistance to phagocytosis. Mutants lacking YopE show reduced virulence in mice, confirming its role in infection.
Area of Science:
- Microbiology
- Pathogen-host interactions
- Bacterial virulence factors
Background:
- The plasmid-encoded YopE protein from Yersinia pseudotuberculosis is a known virulence determinant.
- Understanding the specific mechanisms and roles of YopE in infection is essential.
Purpose of the Study:
- To elucidate the precise role of the YopE protein in the virulence process of Yersinia.
- To investigate YopE's cytotoxic effects and impact on host-pathogen interactions using various model systems.
Main Methods:
- Utilized HeLa cells, mouse macrophages, and live mice as model systems.
- Assessed YopE's cytotoxic activity on cell monolayers.
- Evaluated the influence of YopE on bacterial resistance to phagocytosis.
- Tested the virulence of YopE-deficient mutants following different infection routes (oral, intraperitoneal, intravenous).
Main Results:
- YopE mediates a cytotoxic response on HeLa cells, requiring bacterial adherence.
- YopE induces cytotoxicity in mouse macrophages and impacts bacterial resistance to phagocytosis.
- Mutants lacking YopE expression were avirulent after oral and intraperitoneal infections but remained virulent after intravenous injection.
Conclusions:
- YopE plays a significant role in the virulence of Yersinia.
- The function of YopE appears to be dependent on the route of infection and host environment.