Functionally, we can divide this system into two components. Natural immunity – Barriers and relatively nonspecific responses. Acquired immunity. – Highly specific learned responses. o Physical barriers The Skin and surface fluids. o Inflammation Non-specific response to injury – It involves the blood vessels of any tissue in the body. – It can be triggered by any injury. Bee sting to bullet wound to myocardial infarction. o Natural Killer Cells A watchdog in natural immunity. o Acquired Immunity Acquired immunity is necessary because of the defense strategies adopted by infectious agents. This system is comprised of bone marrow derived cells. Monocyte/macrophage lineage Lymphoid cells T & B cells originate in the bone marrow. B cells continue development in the bone marrow. T cells leave the bone marrow to continue development in the thymus. – At the proper stage of maturation, these cells wander through the body. They are searching for microbial “enemies” and when they spot them, they inform other immune cells. o They are looking for molecules foreign to our body. The foreign molecules are called antigens . Antigens are molecules associated with microbes, foreign cells and anything else that does not belong in the body. o B Lymphocytes and their Role in Immunity o Ultimately, B lymphocytes differentiate into plasma cells. Plasma cells produce antibodies. – Antibodies are globular proteins (immunoglobulin) that react with (bind to) specific antigens.
They are like receptor molecules for which one small portion of an antigen (an epitoph) is their ligand. B cells usually don’t work alone. B cells usually internalize and process antigen, then present the antigen to T cells , which become activated and help the B cell to mount its response. Some B-cells turn into memory cells after being expose to foreign bacteria, viruses or particles. Memory cells are long-lived, and maintain a molecular memory of the event. If the same antigen is encountered again, they will generate a more specific and rapid response. This is the principle behind vaccination. o Vaccination allows your immune system to interact with non-pathogenic forms of antigens. Memory cells are generated by this encounter. If the pathogenic form is later encountered, a rapid and effective response can be initiated.
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- Spring '14
- cells, red blood cells, blood cells—immune cells