Abstract
The enteropathogenic bacteria can bring on infection by overcoming host-defense system such as the intestinal immunity and Flora. The first stage for the bacterial infection is the physical contact between the bacterium and the host cell. The enteropathogenic bacteria adhere or invade the host cell by taking advantage of the physical contact, and can proliferate. Recently, it became clear that one of the tools used by the bacterium upon the bacterium-host contact was the type III secretion machinery. The type III secretion machinery is one of the protein secretion systems for many pathogenic gramnegative bacteria including the enteropathogenic bacteria. The enteropathogenic bacterium send virulence factors directly into the epithelial cell through the type III secretion machinery when coming in contact with the epithelial cell. Therefore, they come to demonstrate the pathogenic without receiving the influence of host-defense system. In 1998, Kubori et al. purified the type III secretion machinery from Salmonella for the first time and clarified its supramolecular structure. Since then, the analysis of type III secretion machinery has advanced rapidly, and the mystery behind host cell infection by pathogenic bacteria is gradually becoming clear. Thus, the type III secretion machinery is one of the clever strategies used so that the enteropathogenic bacteria may bring on infection.
