Structural Model of Antibodies

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Structural Model of Antibodies 

Antibodies are immune system-related proteins called immunoglobulins. Each antibody consists of four polypeptides, two
heavy chains and two light chains
joined to form a "Y" shaped molecule. The amino acid sequence in the tips of the "Y" varies greatly among different antibodies.
This variable region, composed of 110-130 amino acids, give the antibody its specificity for binding antigen. The variable
region includes the ends of the light
and heavy chains. The constant region
determines the mechanism used to
destroy antigen. Antibodies are divided into five major classes, IgM, IgG, IgA, IgD, and IgE, based on their constant region structure and immune function. 





Role of Memory Cells in Immunity

Neither the killer T-cells nor the B-cells just die off after they kill the pathogen. When their job is done, they leave behind memory cells. These memory cells are cells that stay behind and watch for the pathogen. If they find one, they start multiplying to kill it. Memory killer T-cells make killer T-cells and memory B-cells make B-cells. This process is so immediate and so explosive that the pathogen is killed off before it has a chance to infect you. Because of that, you are immune to that

Allergies

Allergies are abnormal reactions to ordinarily harmless substances. These ensitizing substances, called allergens, may be inhaled, swallowed, or come intoc ontact with the skin. Allergens that most frequently cause problems are: pollens,mold spores, house dust mites, animal danders, foods, insect bites or stings, plants,insect spores, latex, viruses, bacteria, medications and environmental conditions( such as cold temperatures).Although allergies can develop at any age, the risk of developing allergies is genetic. It is related to ones family history of allergy. If neither parent is allergic, the chance for allergies is about 15%. If one parent is allergic, the risk increases to 30% and ifboth are allergic, the risk is greater than 60%. Allergens cause the production of immunoglobulin E (IgE), an antibody that all of us have in small amounts. Allergic persons, however, produce IgE in abnormally quantities. Normally, this antibody is important in protecting us from parasites, but not from other allergens. During the sensitization period in allergy, IgE is overproduced. It coats certain potentially explosive cells that contain chemicals including histamine. These chemicals, in turn, cause inflammation and the typical allergic symptoms. This is how the immune system becomes misguided and cause an allergic reaction when stimulated by an allergenom oldebolizom IST ovite brostodols boqolovob and it dom off ni The most common allergic conditions include hay fever (allergic rhinitis), asthma, allergic eyes (allergic conjunctivitis), allergic eczema, hives (urticaria), and allergic shock (also called anaphylaxis and anaphylactic shock). 

Autoimmune disorders 

Autoimmune disorders are diseases that occur when the body produces an inappropriate immune response against its own tissues. Sometimes the immune system will cease to recognize one or more of the body's normal constituents as "self and/or organs. This causes inflammation and damage and leads to autoimmune disorders.infection with bacteria triggers an immune response and the antibodies or T-cells. In a few types of autoimmune disease (such as rheumatic fever), a virus or attack normal cells because some part of their structure resembles a part of the infecting microorganism. Symptoms of autoimmune disorders vary by the particular disorder but many include fatigue, dizziness, and low grade fever. Symptoms can also vary in severity over time.

Some of the autoimmune diseases include:

*Lupus,

 A chronic disease marked by muscle and joint pain and inflammation(the abnormal immune response also may involve attacks on the kidneys and other organs)

*Juvenile rheumatoid arthritis,

 a disease in which the body's immune system acts as though certain body parts (such as the joints of the knee, hand, and foot)are foreign tissue and attacks them. 

*Scleroderma, 


a chronic autoimmune disease that can lead to inflammation and damage of the skin, joints, and internal organs 

*Ankylosing spondylitis, 

a disease that involves inflammation of the spine and joints, causing stiffness and pain 

Juvenile dermatomyositis,

 a disorder marked by inflammation and damage of the skin and muscles

 Role of T-cells and B-cells in Transplant Rejection

Transplantation is the act of transferring cells, tissues, or organs from one site
to another. The malfunction of an organ system can be corrected with transplantation of an organ (e.g kidney, liver, heart, lung, or pancreas) from a donor. However, the immune system remains the most formidable barrier to transplantation as a routine medical treatment. The immune system has developed elaborate and effective mechanisms to combat foreign agents. These mechanisms are also involved in the rejection of transplanted organs, which are recognized as foreign by the recipient's immune system. Major Histocompatibility Complex (MHC) proteins are involved in the presentation of foreign antigens to T-cells, and receptors on the surface of the T-cell (TCR) are uniquely suited to recognition of proteins of this type. MHC are highly variable between individuals, and therefore the T-cells from the host recognize the foreign MHC with a very high frequency leading to powerful immune responses that matched, and are therefore not subject to T-cell mediated rejection. cause rejection of transplanted tissue. Identical twins and cloned tissue are MHC matched, and are therefore not subject to the T-cell mediated rejection. 

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