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The Immune System Period 2 May 23, 1999 The immune system is the most incredible part of our body. It has the task of keeping the body healthy by destroying pathogens and disease-producing organisms, and by neutralizing their toxins. The immune system employs the services of the skin, mucous membranes, hair, cilia, saliva, urine and other natural means of waste disposal to keep the body free of illness and pathogens, For instance, should foreign bacteria enter the body, the immune system will employ cells in the body to fight the invading bacteria, and to prevent their spread. Immune activity has a benefit and a cost. The negative side of immunity is the production of distressing symptoms, acute and chronic diseases.
The term hypersensitivity describes increased, damaging immune response. If you read a textbook of immunology, you get the impression that immune activity only happens occasionally when an infection threatens or an obvious allergic response occurs. You may not realize that immune activity is continuous and is likely to generate symptoms in every person on a regular basis. You do learn from the immunology text that there are many hypersensitivity diseases. You do not learn that non-specific hypersensitivity states are common and produce a variety of ill-defined illnesses. Immune cells circulating in the blood are collectively referred to as white blood cells.
White one the most common medical lab tests. WBC groups include lymphocytes, neutrophils, eosinophils, basophils, and monocytes. These cells are made in the bone marrow and the lymphatic tissues (lymph nodes, thymus, spleen, and gut-associated lymphatic tissue). Some cells identify the characteristic molecular shape of an antigen and respond by proliferation.
A virus, for example, will have protein identifiers stuck to its capsule which mark it, much like an ID badge. Several cell populations will emerge when the virus is present to identify and combat it. One cell group manufactures antibody, a protein specific to one antigen. Molecules in the food supply, especially proteins, act as antigens. Food additives and contaminants may increase the probability of allergic reactions to food. Immune cells do not know the difference between viral, bacterial or food antigens.
We expect and regularly observe similar immune reactions to different antigen sources. A diverse population of cells present antigens to other immune cells, initiating immune responses. These antigen-presenting cells are found, for example, on the surface of blood vessels especially in the liver and spleen. These cells act as monitors and filters of the blood stream. In tissues these cells are called macrophages. Lymphocytes are the cells which recognize antigens presented by macrophages, proliferate after contact with antigens, attack antigen-labelled cells, and manufacture antibodies.
These cells belong to many different functional groups which interact in a complex way, resembling a large military organization. Some T-Lymphocytes (Killer cells or K-cells) act directly to attack cells identified by specific antigen and are responsible for cell-mediated delayed immune-injury. Other T-lymphocytes act as controllers of the antibody-producing cells, the B-Lymphocytes. Controller T-cells fall into groups which remember how to respond to microphages (memory cells) and other groups which enhance immune response (helper cells). Helper cells secrete cytokines activation and growth factors such as interleukin's, which stimulate other cells to act and proliferate. B-lymphocytes are transformed to make antibodies to specific antigens.
B-lymphocytes leave the blood stream and enter the body tissue to produce antibody producers, called plasma cells. Other immune cells attack foreign cells or infecting organisms directly, removing them from the body space. Improperly labeled cells, such the wrong tissue transplanted into a body, will be rejected and destroyed. Transplant surgery is made possible by matching donor and recipient as closely as possible for the same cell labels, known as histocompatibility antigens. Imagine (but do not do) an experiment: make a small cut in the skin of your arm and place a few fibers of meat (ex. scraping from the surface of a steak) in the incision; tape the incision closed and cover with a protective dressing; observe at daily intervals.
The meat fibers include muscle cell components from an animal whose tissue is foreign to yours. Many of these cell components will act as antigens. Immune cells will swarm around the foreign cells and, within 48 hours, local inflammation will set in. The small wound will swell and fester. The typical signs of inflammation, redness, swelling, pain, heat will persist for many days, leaving a scarred lump behind as a permanent reminder of the event. This experiment would illustrate the transplant rejection reaction.
Similar zones of inflammation can be set up in your tissues by meat-fiber antigens arriving via an internal route. Food allergy can trigger events in target organs that resemble transplant rejection! Allergy is a form of hypersensitivity. Autoimmune diseases such as rheumatoid arthritis or multiple sclerosis are also expressions of hypersensitivity. Our basic theory of disease is that many patterns of illness can be explained if we recognize that substances inhaled in air and ingested as foods can trigger a variety of immune responses in any part of the body. Antibodies have a sensing end or antigen recognition site the tips of the y-shaped molecule, which encode antigen recognition in the hyper variable region.
Antibodies also have action sites, which activate complement and / or phagocytic cells the effector system. Antibodies may be free-floating in the serum and combine with antigen to form immune complexes. Or antibodies may be attached to cell-surface antigens, acting as receptors. Antibodies attaching to bacterial cell-surface antigens will activate complement or attract phagocytic cells to trigger bactericidal action.
Antibodies are secreted by B-lymphocytes (transformed to plasma cells in tissue spaces). There are 5 main antibody types: IgA: circulating and secreted on all defended body surfaces, as the first defense against invaders. Secretory (s IgA) is found in large amounts in breast milk, saliva, and gastrointestinal secretions. IgA may be an important and effective antibody in sites other than mucosal tissues, such as the central nervous system. IgA inhibits the binding of microorganisms to mucosal surfaces, preventing entry. IgA plays a similar role in reducing antigen entry through mucosal surfaces.
sIgA deficiency is associated with increased gastrointestinal tract permeability and increased manifestations of delayed patterns of food allergy. Ig D: a surface receptor on lymphocytes. IgE: the antibody which produces typical allergy or immediate hypersensitivity reactions such hay fever, asthma, hives, and anaphylaxis. Its normal function seems to be in anti-parasite defense. This class of immunoglobulins is distributed throughout the body, although the cells synthesizing IgE are predominantly found in association with mucosal tissues.
IgE attaches to mast cells and acts as a receptor to antigen. IgE-bearing cells are found in large numbers in the neonatal GALT, which on maturation revert to IgA and IgM synthesis. Little is known of the traffic of IgE-bearing or IgE-producing cells. If there is traffic of IgE cells it is less extensive than the IgG system; IgE is not found in breast milk, and only in very low amounts in other secretions such as saliva. IgG is the major circulating antibody which enters tissues freely, and participates in diverse immune events.
The IgG antibodies represent a large vocabulary of antigen recognition molecules. There are four subgroups, currently labeled with number suffixes, (IgG 1 to 4). In some mucosal tissues (e. g. mammary glands of ruminants), the IgG 1 class of immunoglobulin-producing cells predominates. IgG (and IgM) activate complement.
IgM: the big, multivalent antibody, capable of capturing and binding antigens to form large insoluble complexes, which are readily cleared from the blood. The isohemagglutinins (anti-A, anti-B), rheumatoid factor, and antibodies to microorganisms are IgM. IgM levels may be elevated in patients with delayed patterns of food allergy, and probably manifest a protective defense response. Secretory IgA is essential to mucosal surface defenses and deficiency of this antibody impairs antigen-exclusion mechanisms. Patients with IgA deficiency are likely to have increased gut permeability to antigens and may show increased evidence of delayed patterns of food allergy and diseases that are related to type 3 and 4 mechanisms i.
e. the autoimmune diseases. An increased incidence of celiac disease, rheumatoid arthritis, SLE, pernicious anemia, pulmonary hemosiderosis has been reported in IgA deficient patients. There is increased incidence of antibodies to food antigens. The diet of patients with IgA deficiency may require adaptive diet revision if symptoms develop the therapeutic strategy is to reduce food antigen loading to compensate for increased antigen entry. This can be done with the Core Program approach to diet revision.
When you get sick, your body is not able to work properly or at its full potential. There are many different ways for you to get sick here are some of them: 1. Mechanical damage. If you break a bone or tear a ligament you will be sick (your body will not be able to perform at its full potential). The cause of the problem is something that is easy to understand and visible.
Vitamin or mineral deficiency. If you do not get enough vitamin D your body is not able to metabolize calcium properly and you get a disease known as rickets. People with rickets have weak bones (they break easily) and deformities because the bones do not grow properly. If you do not get enough vitamin C you get scurvy, which causes swollen and bleeding gums, swollen joints and bruising. If you do not get enough iron you get anemia, and so on. 2. Organ degradation.
In some cases an organ is damaged or weakened. For example, one form of heart disease is caused by obstructions in the blood vessels leading to the heart muscle, so that the heart does not get enough blood. One form of liver disease, known as Cirrhosis, is caused by damage to liver cells (drinking too much alcohol is one cause). 3. Genetic disease. A genetic disease is caused by a coding error in the DNA. The coding error causes too much or too little of certain proteins to be made, and that causes problems at the cellular level.
For example, albinism is caused by a lack of an enzyme called Tyrosinase. That missing enzyme means that the body cannot manufacture melanin, the natural pigment that causes hair color, eye color and tanning. Because of the lack of melanin, people with this genetic problem are extremely sensitive to the UV rays in sunlight. 4. Cancer. Occasionally a cell will change in a way that causes it to reproduce uncontrollably. For example, when cells in the skin called melanocytes are damaged by ultraviolet radiation in sunlight they change in a characteristic way into a cancerous form of cell.
The visible cancer that appears as a tumor on the skin is called melanoma. (See the HSW article on sunburn for more information) 5. Viral or bacterial infection. When a virus or bacteria (also known generically as a germ) invades your body and reproduces, it normally causes problems. Generally the germs presence produces some side effect that makes you sick. For example, the strep throat bacteria (Streptococcus) releases a toxin that causes inflammation in your throat.
The polio virus releases toxins that destroy nerve cells (often leading to paralysis). Some bacteria are benign or beneficial (for example, we all have millions of bacteria in our intestines and they help digest food), but many are harmful once they get into the body or the bloodstream. Viral and bacterial infections are by far the most common causes of illness for most people. They cause things like colds, influenza, measles, mumps, malaria, AIDS and so on.
The job of your immune system is to protect your body from these infections. The immune system protects you in three different ways: 1. It creates a barrier that prevents bacteria and viruses from entering your body. 2. If a bacteria or virus does get into the body, the immune system tries to detect and eliminate it before it can make itself at home and reproduce. 3.
If the virus or bacteria is able to reproduce and start causing problems, your immune system is in charge of eliminating it. The immune system also has several other important jobs. For example, your immune system can detect cancer in early stages and eliminate it in many cases. Once inside the body, a germ deals with the immune system at a different level. The major components of the immune system are: 1. Thymus 2.
Spleen 3. Lymph system 4. Bone marrow 5. White blood cells 6.
Antibodies 7. Complement system 8. Hormones AIDS (Acquired Immune Deficiency Syndrome) is a disease caused by HIV (the Human Immunodeficiency Virus). This is a particularly a problem causing disease for the immune system because the virus actually attacks immune system cells.
In particular, it reproduces inside Helper T cells and kills them in the process. Without Helper T cells to orchestrate things, the immune system eventually collapses and the victim dies of some other infection that the immune system would normally be able to handle. This page shows the reproductive process of HIV very clearly.
Free research essays on topics related to: rheumatoid arthritis, autoimmune diseases, white blood cells, bone marrow, producing cells
Research essay sample on White Blood Cells Rheumatoid Arthritis
