Immunity - The Nature of Disease The • • • • • • Pathogenic Organisms Genetic Disorders Toxic Chemicals Other Environmental Factors

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Unformatted text preview: The Nature of Disease The • • • • • • Pathogenic Organisms Genetic Disorders Toxic Chemicals Other Environmental Factors Physical Damage to Organs Nutritional Disorders Types of Pathogenic Organisms Organisms • • • • • • Viruses Bacteria Protozoan Fungi Animal Parasites Mechanisms of Disease by Pathogens Disease • Utilization of host nutritional Utilization resources resources • Physical damage to host tissues • Production of toxic substances • Chromosomal and gene damage • Body cells behave abnormally Viruse Viruse s Bacteria Bacteria Defense Mechanisms 1. External defense 2. Internal Defense 3. Immune Defense 1 barrier to microbes and viruses • Skin acts asLine of Defense - sweat has a low pH • Mucus traps foreign particles • Tears - Lysozyme has antimicrobial action • Gastric stomach acid Body Coverings: The Skin Body Coverings: The Skin epidermis sebaceous glands sweat gland Body Coverings: Body Coverings: Mucous Membranes mucus cilia columnar epithelium 2 Line of Defense • Phagocytic cells (WBCs) -N L ME B - Natural Killer (NK) Cells: attack virus infected cells • Inflammatory Response • Antimicrobial proteins - Lysozyme - Interferon - Antibodies Nonspecific Phagocytosis Nonspecific Neutrophils Monocytes Eosinophils Mechanism of Phagocytosis Mechanism of Phagocytosis Mechanism Macrophage Lymphatic System Inflammatory Response Histamine & prostaglandins released Capillaries dilate Clotting begins Chemotactic factors attract phagocytic cells Phagocytes consume pathogens & cell debris Characteristics of Immunity Characteristics of Immunity • Recognition of self versus non-self • Response is specific • Retains a “memory” allowing an accelerated second response • Can respond to many different materials • Involves lymphocytes and antibodies Types of Immunity Types of Immunity • Active Immunity - Naturally-Acquired Active Immunity - Artificially-Acquired Active Immunity • Passive Immunity - Naturally-Acquired Passive Immunity - Artificially-Acquired Passive Immunity Types of Acquired Immunity Immunity Active Immunity The production of antibodies against a The specific disease by the immune system. a Naturally acquired through disease Naturally a Artificially acquired through vaccination Artificially a • Vaccines include inactivated toxins, killed Vaccines microbes, parts of microbes, and viable but weakened microbes. weakened a Active immunity is usually permanent a A vaccinated person has a secondary vaccinated response based on memory cells when encountering the specific pathogen. encountering • Routine immunization against infectious Routine diseases such as measles and whooping cough, and has led to the eradication of smallpox, a viral disease. smallpox, • Unfortunately, not all infectious agents are Unfortunately, easily managed by vaccination. easily – HIV vaccine in the works Passive Immunity a Passive Immunity- Protection Protection against disease through antibodies produced by another human being or animal. a Effective, but temporary a Ex. Maternal antibodies a Colostrum. a Passive immunity can be transferred Passive artificially by injecting antibodies from an animal that is already immune to a disease into another animal. into • Rabies treatment: injection with antibodies Rabies against rabies virus that are both passive immunizations (the immediate fight) and active immunizations immunizations (longer term defense). immunizations Immune System Response to Immune System Response to Antigens Humoral Immunity • Involves antibodies (secreted from B cells) dissolved in the blood plasma. • Demonstrated as a immune response using only the blood serum. • Defense against bacteria, bacterial toxins, & viruses. Immune System Response to Antigens Cell-Mediated Immunity • Involves the activities of specific white blood cells (T cells). • Defense against cancer cells, virusinfected cells, fungi, animal parasites, & foreign cells from transplants. Lymphocyte Formation B Cells B Cells • Mature in bone marrow • Involved in humoral immunity • Once activated by antigen, proliferate into two clones of cells: plasma cells that secrete antibodies and memory cells that may be converted into plasma cells at a later time B Cells B Cells antibodies B Cells Cells B Cells Activation of B Cells by Antigen Antigen antigen Clonal Selection Clonal Selection Clonal Selection Clonal Selection plasma cells memory cells antibodies Overview of Immune System Responses antibody concentration Humoral Immune Response Humoral first exposure to antigen A time (days) antibody concentration Humoral Immune Response Humoral first exposure to antigen A primary response: concentration of second exposure antibody anti-A to antigen A time (days) antibody concentration Humoral Immune Response Humoral secondary response: concentration of anti-A antibody second exposure to antigen A first exposure to antigen B time (days) antibody concentration Humoral Immune Response Humoral primary response: concentration of anti-B antibody first exposure to antigen B time (days) Antibody Molecule Antibody Molecule antigen binding sites antigen light chains heavy chains Mechanisms on Antibody Mechanisms on Antibody Action • • • • • • Precipitation of soluble antigens Agglutination of foreign cells Neutralization Enhanced phagocytosis Complement activation leading to cell lysis Stimulates inflammation a The binding of antibodies to antigens to form The antigen-antibody complexes is the basis of several antigen disposal mechanisms. several The classical complimentary pathway, resulting in lysis of a target cell T Cells Cells • Mature in thymus • Involved in cell-mediated immunity • Activated when another cell presents antigen to them • Several types of T cells: cytoxic T cells, helper T cells, suppressor T cells, and memory T cells T Cells – Helper T cells (TH) - stimulates B and cytotoxic T lymphocytes – Cytotoxic T cells (TC) – lyses cells – Suppressor T cell (TS) suppresses antibody production after successfully tackling an invading organism – Memory T cell (TM) – rapidly divides upon reexposure to the same antigen – Natural Killer cells (NK) - mechanism similar to T cytotoxic cells, but less specific response. Important in elimination of tumors and virus- Cytotoxic T Cell Cytotoxic perforin pores in target cell Helper T Cells Helper T Cells bacterial T cell receptor bacterium antigens helper T cell macrophage interleukin 1 The central role of helper T cells a The central role in Helper T cells in an The infected cell infected a T-dependent T-dependent antigens- can trigger a antigens can humoral immune response by B cells only with the participation of helper T cells. cells. Tissue/Organ Transplants Tissue/Organ • Major Histocomatibility Complex (MHC) - Bone marrow - Organs ABO Blood Types ABO Blood Type O A B AB AB Rh Rh Antigen Antigen A B AB + Antibody Antibody antibody anti a & b antibody anti b antibody anti a - Universal Donor ? Universal Recipient ? Abnormal immune function can Abnormal lead to disease lead a Malfunctions of the immune system may Malfunctions result in: result • minor inconvenience of some allergies minor • serious and often fatal consequences of serious certain autoimmune and immunodeficiency diseases. diseases. Abnormal Immune Abnormal Immune Function • Autoimmune Disease • Allergy • Immunodeficiency Autoimmune Disease Autoimmune • • • • • • Rheumatoid arthritis Type I Diabetes MS Lupis Crohn’s disease Grave’s disease Allergy (Immune Hypersensitivity) Hypersensitivity) • Hypersensitive response to certain environmental allergens • Food, pollen, pet dander, asthma, bee sting • Anaphylactic shock - epinephrine a Mast cells, IgE, Mast and the allergic response. response. AIDS Problems Acquired Immunodeficiency Syndrome HIV (virus) attacks T-cells Weakens or eliminates immune system Susceptible to many fatal diseases a Transmission of HIV requires the transfer of Transmission body fluids containing infected cells, such as semen or blood, from person to person. semen • • • Unprotected sex Unprotected Nonsterile needles Nonsterile HIV transmission among heterosexuals is HIV rapidly increasing as a result of unprotected sex with infected partners. with • HIV in Africa and Asia- primarily by heterosexual HIV sex sex AIDS AIDS • In 1983, a retrovirus, now called human immunodeficiency virus (HIV), had been identified as the causative agent of AIDS. HIV budding Living w/AIDS Cumulative cases HIV/AIDS in Hawaii 2720 2833 2770 2585 3,000 2,500 2,000 1,500 987 1,000 500 2461 1070 1247 1318 1271 2000 2001 2002 2003 2004 a With the AIDS mortality close to 100%, HIV With is the most lethal pathogen ever encountered. encountered. • Molecular studies reveal that the virus probably Molecular evolved from another HIV-like virus in chimpanzees in central Africa and appeared in humans sometimes between 1915 and 1940. humans – These first rare cases of infection and AIDS went These unrecognized. unrecognized. AIDS AIDS AIDS AIDS a HIV Testing: • The HIV antibody test has be used to screen The all blood supplies in the U.S. since 1985. all – May take weeks or months before anti-HIV May antibodies become detectable. antibodies - Drug treatment available - Best prevention is education and protected sex 1. What are the proteins secreted by plasma cells called? 2. Which cell terminates or decreases the immune response? 3. Which type of T cell lyses cells that have been infected with a virus? 4. Which cell provides an accelerated immune response upon second exposure to a particular antigen? 5. A disease in which a person’s immune system attacks a persons own normal tissue is called _____? INQUIRY ...
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This note was uploaded on 04/19/2011 for the course BIOL 101 taught by Professor Wong during the Fall '09 term at University of Hawaii, Manoa.

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