The superantigenic toxin of Yersinia pseudotuberculosis: a novel virulence factor?
Recently, a superantigenic toxin designated YPM (Yersinia pseudotuberculosis-derived mitogen) was characterized in the supernatant of Y. pseudotuberculosis, a Gram-negative bacterium involved in human enteric infection. To assess the role of YPM in pathophysiology of Y. pseudotuberculosis, a superantigen-deficient mutant was constructed and its virulence was tested in a murine model of infection and compared with the virulence of the wild-type strain (wt). Determination of the survival rate after intravenous inoculation of mice clearly demonstrated a higher survival rate when animals were infected with the superantigen-deficient strain. This decreased virulence of the mutant strain could not be explained by a lower bacterial growth rate in spleen, liver or lung of infected animals. Therefore, production of IFNgamma, TNFalpha, IL-2, IL-6 and IL-10 was followed during the course of infection by cytokine assay in the blood and mRNA detection in the spleen. IL-6 and IFNgamma were the two major cytokines detected whereas TNFalpha production was never observed.
Carnoy
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Equipe Mixte INSERM E 9919, Université JE 2225, Institut de Biologie de Lille, France. christophe.carnoy@ibl.fr
Müller-Alouf
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Desreumaux
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Mullet
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Grangette
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Simonet
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D000818:Animals; D001426:Bacterial Proteins / Q000633:toxicity*; D006801:Humans; D008934:Mitogens / Q000633:toxicity*; D018089:Superantigens / Q000633:toxicity*; D014774:Virulence; D015011:Yersinia pseudotuberculosis / Q000472:pathogenicity*
D001426:Bacterial Proteins; D008934:Mitogens; D018089:Superantigens; C093313:Yersinia pseudotuberculosis-derived mitogen