Immunological reactions on H. pylori infection

Abstract

An immune network that responds to bacteria as a mucous membrane defense factor is called gut-associated lymphoid tissue (GALT), which is made up of distinctive tissues of B cell, T cell, and phagocytes. The purpose of GALT is to maintain stomach homeostasis via interaction between immune and nonimmune mechanisms. Actually stomach immune mechanism is mostly about Helicobacter pylori (H. pylori). Long-term H. pylori proliferation indicates failure of gastric immune mechanisms that causes chronic H. pylori inflammation, and various diseases emerge as a result. H. pylori delicately regulate innate and adaptive immunities to evade from host immunity. Especially, H. pylori disrupt T-cell activity such as Th1/ Th2 immunological reaction balance. Th1 produces cytokines like interferon-y and interleukin (IL)-2, and Th2 produces cytokines like IL-4, IL-5, IL-10, and IL-13 and engages with differentiation and activation of B cell. Finally it causes gastritis, peptic ulcer, and mucosa-associated lymphoid tissue (MALT) lymphoma and increases risk of gastric cancer.