Even though chronic gastritis was well established as a risk factor for the development of several gastric pathologies, such as peptic ulceration, gastric carcinoma, and lymphoma, before the discovery of Helicobacter pylori by Warren and Marshall in 1983 (Warren, 1983), the development of chronic gastritis was thought to be due to a plethora of possible causes such as stress, excessive alcohol consumption, ingestion of hot beverages and spicy food, among others (Mobley et al., 2001). With the association of Helicobacter pylori as the cause of chronic gastritis, the understanding of bacterial pathogenicity and the host response against the bacterium take enormous importance to understand the pathophysiology of the infection.