The Type III secretion system of pathogenic Yersinia
There are three human pathogenic strains of Yersinia; Y.pestis , Y.pseudotuberculosis and Y.enterocolitica . Y.pestis is the causative agent of plague; and was responsible for the Black death during the 14th century. This family of bacteria harbours a common virulence plasmid which encodes a number of secreted proteins collectively called Yops (Yersinia outer proteins). These proteins are expressed during infection and they are major antihost factors.
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