Innate immunity represents the first line of defense against a wide range of pathogens or damage signals and plays key roles in generating a protective inflammatory response as well as activating and instructing the adaptive immune response. It is present at birth and can pass down genetically from parents to children.
Previously, innate immunity was characterized by a rapid, nonspecific immune response to pathogens. However, recent studies demonstrate that innate immune responses show a greater degree of specificity to discriminate self from pathogens than previously appreciated. Furthermore, innate immunity is the master regulator of all immune responses and plays a key role in the activation of adaptive immunity. As the first line of defense, the innate immune system has three main components to allow for rapid and efficient removal of invading pathogens: barriers and cellular and humoral effector components.