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Immune System

Immune System. Chris Schneider. Immune System Function. The purpose of the immune system is to keep infectious microorganisms, such as certain bacteria, viruses, and fungi, out of the body, and to destroy any infectious microorganisms that do invade the body .

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Immune System

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  1. Immune System Chris Schneider

  2. Immune SystemFunction • The purpose of the immune system is to keep infectious microorganisms, such as certain bacteria, viruses, and fungi, out of the body, and to destroy any infectious microorganisms that do invade the body. • The immune system is made up of a complex and vital network of cells and organs that protect the body from infection.

  3. Immune SystemHow it recognizes • Through a process called affinity maturation. Affinity maturation involves a subset of lymphocytes, called B-cells because they mature in the bone marrow. A B-cell is activated by binding to the pathogen. It secretes a soluble form of its receptors, called antibodies, which bind to pathogens and inactivates them, or identify them to phagocytes and other innate system defenses, which allows the innate system to eliminate them.

  4. Immune SystemInnate and aquired immunity • Theinnate immune system consists of cells and proteins that are always present and ready to mobilize and fight microbes at the site of infection. • The main components of the innate immune system are 1) physical epithelial barriers, 2) phagocytic leukocytes, 3) dendritic cells, 4) a special type of lymphocyte called a natural killer (NK) cell, and 5) circulating plasma proteins. • Theadaptive immune system, on the other hand, is called into action against pathogens that are able to evade or overcome innate immune defenses. • Components of the adaptive immune system are normally silent; however, when activated, these components “adapt” to the presence of infectious agents by activating, proliferating, and creating potent mechanisms for neutralizing or eliminating the microbes. • There are two types of adaptive immune responses: humoral immunity, mediated by antibodies produced by B lymphocytes, and cell-mediated immunity, mediated by T lymphocytes.

  5. Immune SystemPassive immunity • Passive immunity is attained 2 ways. First, is that when you're born, you receive antibodies from your mother, actually most frequently from breast milk. Another way is to receive an antibody serum, called an "antidote" in movies...this treatment exists, but is rare and impractical. • Passive immunity can help in an emergency, but such emergencies are rare. Active immunity, if you have the time to allow antibodies to be built up, then this is the best method.

  6. Immune SystemActive immunity • Active immunity is immunity that occurs when YOUR BODY makes the antibodies. That is, if you get strep throat, your body makes antibodies for streptococcus whatever. You will be resistant to this bacteria for years, maybe you'll never get sick from it again. The same goes for illnesses like chicken pox, the flu, and many colds. • Active immunity is also attained by receiving a vaccine. A dead or attenuated virus is injected in your bloodstream and you make antibodies.

  7. Immune SystemHumoral immunity • The humoral response involves B cells that recognize antigens or pathogens that are circulating in the lymph or blood. The response follows this chain of events: • Antigens bind to B cells. • Interleukins or helper T cells costimulate B cells. In most cases, both an antigen and a costimulator are required to activate a B cell and initiate B cell proliferation. • B cells proliferate and produce plasma cells. The plasma cells bear antibodies with the identical antigen specificity as the antigen receptors of the activated B cells. The antibodies are released and circulate through the body, binding to antigens. • B cells produce memory cells. Memory cells provide future immunity.

  8. Immune SystemCell Mediated immunity • The cell-mediated response involves mostly T cells and responds to any cell that displays aberrant MHC markers, including cells invaded by pathogens, tumor cells, or transplanted cells. The following chain of events describes this immune response: • Self cells or APCs displaying foreign antigens bind to T cells. • Interleukins (secreted by APCs or helper T cells) costimulate activation of T cells. • If MHC-I and endogenous antigens are displayed on the plasma membrane, T cells proliferate, producing cytotoxic T cells. Cytotoxic T cells destroy cells displaying the antigens. • If MHC-II and exogenous antigens are displayed on the plasma membrane, T cells proliferate, producing helper T cells. Helper T cells release interleukins (and other cytokines), which stimulate B cells to produce antibodies that bind to the antigens and stimulate nonspecific agents (NK and macrophages) to destroy the antigens.

  9. Immune SystemBacteria vs Virus • Antibiotics do not work on viruses because viruses are not alive. • A bacterium is a living, reproducing life form. • A virus is just a piece of DNA. • A virus injects its DNA into a living cell and has that cell reproduce more of the viral DNA. • With a virus there is nothing to "kill," so antibiotics don't work on it.

  10. Immune SystemHIV/AIDS • AIDS is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight the organisms that cause disease. • HIV is a sexually transmitted infection. It can also be spread by contact with infected blood, or from mother to child during pregnancy, childbirth or breast-feeding. It can take years before HIV weakens your immune system to the point that you have AIDS.

  11. Immune SystemHIV/AIDS • The majority of people infected by HIV develop a flu-like illness within a month or two after the virus enters the body. This illness, known as primary or acute HIV infection, may last for a few weeks. Possible symptoms include: • Fever • Muscle soreness • Rash • Headache • There are 1.1 million people in the U.S. with aids. That is about .6% • There is currently no cure to HIV/AIDS

  12. Immune SystemImmunodeficiency • Primary immunodeficiency disorders — also called primary immune disorders or primary immunodeficiency — weaken the immune system, allowing repeated infections and other health problems to occur more easily. • Signs and Symptoms include • Frequent and recurrent ear infections, pneumonia, meningitis, bronchitis, sinus infections or skin infections • Blood infections • 1 in every 1200 people has this disease. • One can take place in stem cell transplantation.

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