The Interaction Study Of Helicobacter Pylori And Gastric Epithelial Cells

Helicobacter pylori (H.pylori) is a spiral-shaped Gram-negative micro-aerophilic bacterium discovered in 1983. It colonizes the human stomach and persists for several decades, causing many digestive disease, such as chronic gastritis and peptic ulcer diseases. Recent epidemiological studies have further indicated that H. pylori infection is closely associated with the development of gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue lymphoma. WHO has regarded this bacterium as the first carcinogenic factor. But the carcinogenesis mechanism of H.pylori is not clear now.CagA is a very important virulence factor secreted by H.pylori.The H. pylori cagA gene encodes the 120- to 145-kDa CagA protein. Recent research have shown that CagA positive strains are considered to be more virulent than cagA -negative strains.Consistently, molecular epidemiological studies have suggested that cagA-positive H. pylori infection significantly increases the risk of gastric carcinoma compared with CagA -negative strain. During the infection of cagA -positive strains, the CagA protein is translocated from the bacteria into the attached epithelial cells via the bacterial type IV injection apparatus. The translocated CagA protein then localizes...