The immune system is designed to protect the host from infectious agents and tumor cells that may arise during a lifetime of exposure to a variety of insults, and to eliminate foreign, potentially toxic chemicals.
In a broad sense, there are two major effector pathways that the immune system uses to protect the host: innate and adaptive immunity. Both innate and adaptive immune responses contribute to the pathophysiology of all inflammatory diseases. Both adaptive and innate immunity share common effector molecules, particularly the proinflammatory cytokines such as TNFα and IL1 -beta;. These mediators are critical for cell-cell interactions, activation and migration of effector cells, and the generation of an effective immune response.
Image: Example of Innate Immunity
Innate immunity is designed to respond rapidly to foreign invaders (i.e., bacteria, viruses, and parasites), but does not develop a long-lasting memory. It is the first line of defense for the body.
Blocking the innate immune response may result in infection or malignancies.
Image: Example of Adaptive Immunity
Adaptive immunity takes longer to develop, occurring after the primary exposure to a pathogen, vaccination, or experimental immunization. In autoimmune disease, the adaptive immune response is directed against the body’s own tissues.
The adaptive immune response is long lasting and creates a pool of memory T cells (CD4+ T cells) that are kept permanently to fight future pathogens. In autoimmune disease, these T cells think the body is the invader, so they continue to attack the body for the rest of the person’s life. At this time, we cannot safely remove these T cells from the body so it is necessary to develop other ways to block their destructive action.
