NR 507 Week 1 Assignment; Immune Response

Type II Hypersensi琀椀vity Reac琀椀on A Type II hypersensi琀椀vity reac琀椀on is 琀椀ssue-speci昀椀c and usually occurs as a result of haptens that cause an IgG an琀椀body or IgM an琀椀body mediated response. The an琀椀bodies are speci昀椀cally directed to the an琀椀gen located on the cell membrane. A hapten is a small molecule that can cause an immune response when it a琀琀aches to a protein. Macrophages are the primary e昀昀ector cells of Type II responses. Typical examples of Type II reac琀椀ons are drug allergies, as well as allergies against infec琀椀ous agents. The Type II response begins with the an琀椀body binding to the an琀椀gen and may cause the following. • The cell to be destroyed by the an琀椀body • Cell destruc琀椀on through phagocytosis by macrophages • Damage to the cell by neutrophils triggering phagocytosis • Natural killer cells to release toxic substances that destroy the target cell • Malfunc琀椀on of the cell without destruc琀椀on Examples of type II reac琀椀ons include drug allergies, hemoly琀椀c anemia, blood transfusion mismatch with resul琀椀ng transfusion reac琀椀on and Rh hemoly琀椀c disease. Type III Immune-Complex Reac琀椀on The Type III hypersensi琀椀vity reac琀椀on is also an an琀椀gen-an琀椀body response. The major di昀昀erence between Type II and Type III responses is that in a Type II response, the an琀椀body binds to the an琀椀gen on the cell surface, but in Type III responses, the an琀椀body binds to the an琀椀gen in the blood or body 昀氀uids and then circulates to the 琀椀ssue. Type III reac琀椀ons are not organ speci昀椀c and use neutrophils as the primary e昀昀ector cell. In type III hypersensi琀椀vity reac琀椀ons immune complex deposi琀椀on (ICD) causes autoimmune diseases, which is o昀琀en a complica琀椀on. As the disease progresses a more accumula琀椀on of immune complexes occurs, and when the body becomes overloaded the complexes are deposited in the 琀椀ssues and cause in昀氀amma琀椀on as the mononuclear phagocytes, erythrocytes, and complement system fail to remove immune complexes from the blood. One of the classic Type III reac琀椀ons is serum sickness. Type IV Cell-Mediated, Delayed Reac琀椀on The type IV hypersensi琀椀vity reac琀椀ons are known as cell-mediated responses and use lymphocytes and macrophages as primary mediators. Unlike the 昀椀rst three types of responses, which are humoral immune func琀椀ons, a Type IV response is mediated by T-lymphocytes and does not use an琀椀bodies. A typical reac琀椀on from a Type IV cell-mediated response would be a localized contact derma琀椀琀椀s. When the individual comes in contact with the an琀椀gen, T cells are ac琀椀vated and move to the area of the an琀椀gen. The an琀椀gen is taken up, processed, and presented to macrophages, leading to epidermal reac琀椀ons characterized by erythema, cellular in昀椀ltra琀椀on and vesicles. This process is illustrated in contact derma琀椀琀椀s on the next page. ing immune system, the individual becomes suscep琀椀ble to opportunis琀椀c infec琀椀ons, cancer, neurological dis eases, was琀椀ng and death. • Primary o Chronic granulomatous Disease of Childhood o DiGeorge Syndrome o Job Syndrome o Common Variable Immunode昀椀ciency o Familial Mediterranean fever • Secondary o Human Immunode昀椀ciency Virus o Pneumocys琀椀s Carinii o Pneumonia o Sinus infec琀椀on o Lung cancer Autoimmunity Autoimmune Disease Autoimmunity is an altera琀椀on in the ability