* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Helper T cells - Plain Local Schools
Survey
Document related concepts
Immunocontraception wikipedia , lookup
Sociality and disease transmission wikipedia , lookup
DNA vaccination wikipedia , lookup
Lymphopoiesis wikipedia , lookup
Hygiene hypothesis wikipedia , lookup
Monoclonal antibody wikipedia , lookup
Sjögren syndrome wikipedia , lookup
Immune system wikipedia , lookup
Molecular mimicry wikipedia , lookup
Adaptive immune system wikipedia , lookup
Psychoneuroimmunology wikipedia , lookup
Adoptive cell transfer wikipedia , lookup
Cancer immunotherapy wikipedia , lookup
Immunosuppressive drug wikipedia , lookup
Transcript
31.1 Infectious disease caused by pathogens Germ theory _______________________________________________________________________ _______________________________________________________________________ Germ theory was pioneered by the work of several scientists whose discoveries each built upon one another Louis Pasteur Pasteur(a French chemist) is best known for his method of sterilizing milk (pasteurization) using gentle heat Pasteur made several observations involving interference with alcohol fermentation by microorganisms ________________________________________________________________________ ________________________________________________________________________ Joseph Lister ________________________________________________________________________ ________________________________________________________________________ Influenced by Pasteur’s notion that microorganisms cause disease he began treating his surgical equipment with chemicals to kill any microbes that may be present Death from infection rates in the hospital he worked in dropped significantly after he started this practice _______________________________________________________________________ _______________________________________________________________________ Robert Koch _______________________________________________________________________ _______________________________________________________________________ This methodology (known as Koch’s Postulates) is still used today (see handout) 1 Disease Transmission Infectious disease can be transmitted by one of the following ways: 1. 2. 3. 4. 5. 31.2 The Body’s defense The Human body has three lines of defense against infectious disease: 1. Barriers - External Nonspecific Defenses 2. Internal Nonspecific Defenses 3. 1) Barriers (physical and chemical) _____________________________________________________________________ ______________________________________________________________________ Sweat glands in skin secrete acids and oils which act as a chemical barrier to pathogens Sweat contains an enzyme (lysozyme) which breaks down cell walls of many bacteria _____________________________________________________________________ _____________________________________________________________________ Your nose is protected by the fine hairs inside which are lined with mucus Mucus also is found in the digestive and respiratory pathways and is a sticky barrier which germs often get stuck in ________________________________________________________________________ _________________________________________________________________________ 2) Internal Nonspecific Defenses a) Pathogen-destroying white blood cells Macrophages (big eater) – a large type of WBC that engulfs foreign bodies and destroys them by phagocytosis…once inside the macrophage, enzymes are used to kill the pathogen Neutrophils – smaller and more numerous than macrophages… like macrophages neutrophils engulf invaders and release chemicals to kill them but these chemicals kill the neutrophil as well 2 ________________________________________________________________ b) Inflammatory response If a pathogen gets past the first line of defense it may trigger the inflammatory response When the skin is broken, like in a cut, the broken tissue (mast cells) secretes chemicals called histamines that cause vessels to expand (dilate)…this will increase blood flow to the area and cause the swelling, redness, and heat associated with an injury _______________________________________________________________________ _______________________________________________________________________ If pathogens get into the blood stream and circulate throughout the body…your entire body may trigger an inflammatory response (we call it a fever) A fever may be dangerous if it rages out of control…but a mild fever can help stimulate more WBC’ s which can help destroy the pathogen c) Specialized proteins Chemicals produced by cells in response to being infected by a virus ______________________________________________________________________ ______________________________________________________________________ The infected cell may die but the specialized protein it produces will stimulate nearby cells to do the same…a large number of cells together may produce enough of the specialized protein to destroy the viruses or block their reproduction…ex. – Interferon 3) Targeted Defense The third line of defense against infectious disease is your body’s immune system The immune system targets specific pathogens, cancer cells, and certain chemicals _______________________________________________________________________ ________________________________________________________________________ The attack may take longer but is longer lasting and more effective 31.3 The Immune System Antigens The surfaces of viruses, bacteria, fungi, cancer cells, pollen and other cells contain certain molecules called antigens 3 ______________________________________________________________________ ______________________________________________________________________ Antigen means “antibody-generating” Each pathogen’s antigen has it’s own unique shape Antibodies Antibodies are proteins that attach to particular antigens Antibodies are found on the surface of certain white blood cells or in blood plasma _____________________________________________________________________ _____________________________________________________________________ These binding sites shapes fit specifically to certain antigens that are the same shape (like two pieces of a puzzle) Antibodies “tag” invaders by binding to the antigen molecules Antibodies neutralize or destroy invaders in a variety of ways: a. it could prevent a virus from entering a host cell b. ____________________________________________________________________ c. it could cause pathogens to clump together making them an easy target for phagocytes All of these responses involve a specific recognition followed by a non-specific destruction Lymphocytes This is the name given to white blood cells that recognize specific invaders _______________________________________________________________________ Two types of lymphocytes are B and T cells B and T cells differ from one another and amongst themselves as well ________________________________________________________________________ Humoral Immunity Provided by B cells B cells provide immunity and protection outside of cells in body fluids 4 _______________________________________________________________________ All the plasma cells will produce the same antibody (the one that works) until the invader is destroyed or stopped Cell-Mediated immunity Provided by T cells T cells operate by attacking infected body cells ________________________________________________________________________ If a T cell has a matching receptor site then it activates and produces a clone army (cytotoxic T cells…aka killer T cellls) The army will bind to other infected cells and poke holes in them by producing a chemical called perforin _______________________________________________________________________ T cells are also critical to the “in house” prevention of cancer T cells can kill cancer cells in the same way that they destroy infected body cells Why this system sometimes fails is a critical aspect of cancer research Helper T cells Helper T cells help boost both humoral and cell mediated immunity Like other WBC’ s, helper T cells have binding sites that bind to known antigens _______________________________________________________________________ Once a pathogen antigen is identified on a macrophage the helper T cells begin secreting chemicals that call cytotoxic T cells and B cells into action Primary Immunity The first time that T or B cells battle a new pathogen it is known as the primary immune response The primary response is slow and weak because time is needed for the proper cell with the correct binding site to be found as well as the tome needed to generate a clone army large enough to defeat the invader 5 _____________________________________________________________________ These memory cells will be used if there is ever a repeat visit by the intruder Secondary Immunity After the primary immune response, the memory T or B cells that remain in the body are poised to spring into action immediately if the pathogen ever returns ________________________________________________________________________ This stronger and quicker response to infection is called the secondary response 31.4 Vaccinations Vaccines and natural immunity Natural immunity is gained after being infected by a pathogen or receiving a vaccination ________________________________________________________________________ A vaccine is a dose of a weakened or inactive pathogen...or part of a pathogen’s antigen that stimulates the primary immune response ________________________________________________________________________ What is a vaccine made of? Some vaccines are made of only the pathogen’s antigen ________________________________________________________________________ Some vaccines consist of a slightly different version of the pathogen that “fools” the body into reacting (EX. Cowpox for Smallpox) Booster shots are given for some vaccines to boost antibody production and strengthen the memory cells that were created after the first exposure Active Immunity Active immunity is developed whenever a body produces it’s own antibodies against an infection 6 ________________________________________________________________________ Passive Immunity Receiving already synthesized antibodies gives us passive immunity ________________________________________________________________________ Passive immunity provides only temporary protection against infection because the antibodies will disintegrate over time…and no memory cells will be produced…remember only the primary immune response can provide long term protection 31.5 Immune system disorders Allergies ________________________________________________________________________ Most allergens stimulate mast cells to produce histamine Histamine triggers the inflammatory response, which produces the characteristic symptoms of watery eyes, runny nose, sneezing, etc. Some allergies may be life threatening if serious enough to cause a sudden dramatic drop in blood pressure and a breathing arrest – a condition known as anaphylactic shock ________________________________________________________________________ Autoimmune Disease Occurs when the bodies immune system turns against it’s own molecules (can’t distinguish “self” from “non-self”) Examples: a. ___________________________________________________________________ ___________________________________________________________________ b. Rheumatoid arthritis – the immune system attacks cartilage and bone joints causing damage and painful debilitating inflammation c. Multiple Sclerosis- T cells attack parts of nerve cells and interfere with the transmission of nerve signals – symptoms range from fatigue and numbness to difficulties with walking, talking, concentrating, and even memory loss Autoimmune disorders are treated by either replacing lost “self” molecules, suppressing the immune system, or just treating the symptoms themselves 7 AIDS – A Disease of the Immune System Stands for Acquired Immune Deficiency Syndrome AIDS is caused by HIV – Human Immunodeficiency Virus HIV attacks primarily the helper T cells ________________________________________________________________________ Both humoral and cell mediated immunity are affected…leaving the body open to infections such as pneumonia or death from certain forms of cancer AIDS is transmitted primarily through sexual contact or through contaminated blood via shared drug needles Because HIV is a retrovirus it mutates rapidly…therefore no vaccine can be produced Organ Transplants Transplanted organs are often viewed as “non-self” by the bodies immune system and are attacked ________________________________________________________________________ These drugs however leave the body vulnerable to infection from other sources Transplants that have the fewest complications are those between identical twins Healthy Immune system A healthy Immune system is supported by a balanced diet…good hygiene…good sleep…and an avoidance of stress ________________________________________________________________________ 8