The Immune System Chapter 15 www.freelivedoctor.com
Defense Mechanisms <ul><li>The Immune system </li></ul><ul><ul><li>All structures and processes that provide a defense aga...
Defense Mechanisms <ul><li>Immune defenses identify self from non-self </li></ul><ul><ul><li>Protect against microbes </li...
Defense Mechanisms <ul><li>Immunology </li></ul><ul><ul><li>Study of physiological defenses by which the host destroys or ...
Immunity <ul><li>Nonspecific immunity </li></ul><ul><ul><li>Characteristics </li></ul></ul><ul><ul><ul><li>Can respond imm...
The Players <ul><li>Cells </li></ul><ul><ul><li>All leukocytes </li></ul></ul><ul><ul><li>Notable derivatives or relations...
The Players <ul><li>Chemicals </li></ul><ul><ul><li>Cytokines </li></ul></ul><ul><ul><ul><li>Protein messengers released f...
Nonspecific Immunity <ul><li>General information: </li></ul><ul><ul><li>Also called nonspecific body defenses </li></ul></...
Nonspecific Immunity: MB <ul><li>Surface Membrane Barriers </li></ul><ul><li>First Line of Defense  </li></ul><ul><ul><li>...
Nonspecific Immunity: MB <ul><li>Protective Chemicals </li></ul><ul><ul><li>Acid pH of skin secretions </li></ul></ul><ul>...
Nonspecific Immunity: cells and chemicals <ul><li>OVERVIEW </li></ul><ul><li>Enormous number of cellular and chemical defe...
Nonspecific Immunity: cells and chemicals <ul><li>OVERVIEW: continued </li></ul><ul><li>Most significant methods: </li></u...
Nonspecific Immunity: cells and chemicals <ul><li>OVERVIEW: continued </li></ul><ul><ul><li>Antimicrobial Substances </li>...
Nonspecific Immunity: cells and chemicals <ul><li>Phagocytosis: ingestion and destruction of particulate matter </li></ul>...
Phagocytosis <ul><li>Method of Action </li></ul><ul><ul><li>Ingestion </li></ul></ul><ul><ul><ul><li>Form PHAGOSOME </li><...
Phagocytosis <ul><li>Neutrophils and monocytes are able to squeeze through tiny gaps between adjacent endothelial cells. <...
Phagocytosis <ul><li>Destruction </li></ul><ul><ul><li>By macrophages and neutrophils </li></ul></ul><ul><ul><li>Intracell...
Phagocytosis <ul><li>Phagocytes engulf particles similar to amoeba. </li></ul><ul><ul><li>Particle becomes surrounded by p...
Phagocytes Intracellular killing of microbes Regulate inflammation Extracellular killing Activation of clotting or anti-cl...
Natural Killer (NK) Cells <ul><li>Lymphocytes that are related to T cells. </li></ul><ul><li>Do not need specific antigen ...
Inflammatory Response <ul><li>Second major kind of nonspecific cellular and chemical defense </li></ul><ul><ul><li>Conside...
Inflammatory Response <ul><li>Principle effects </li></ul><ul><ul><li>Prevents spread of injurious agent </li></ul></ul><u...
Local Inflammation <ul><li>Inflammatory reaction initiated by phagocytosis and complement activation. </li></ul><ul><li>Co...
Local Inflammation <ul><li>Leukocytes interact with adhesion molecules in endothelial cell. </li></ul><ul><li>Chemotaxis a...
Local Inflammation <ul><li>Mast cells release histamine and secrete TNF-alpha. </li></ul><ul><ul><li>Increases membrane pe...
Local Inflammation <ul><li>Characteristic effects of inflammation: </li></ul><ul><ul><li>Redness and warmth.  </li></ul></...
Antimicrobial Substances <ul><li>Third major kind of nonspecific cellular and chemical defense </li></ul><ul><li>Includes ...
Complement <ul><li>Also called the complement system </li></ul><ul><li>General points </li></ul><ul><ul><li>Group of ~ 20 ...
Complement Proteins <ul><li>Complements (or enhances) nonspecific and specific defenses.  </li></ul><ul><li>The combinatio...
Activated Complement Proteins Direct destruction by MAC  (membrane attack complex) Vasodilation Increased capillary permea...
<ul><li>Two major pathways. </li></ul><ul><li>Classical : </li></ul><ul><ul><li>11 proteins </li></ul></ul><ul><ul><ul><li...
<ul><li>Classical </li></ul><ul><li>11 complement proteins, designated C-1 to C-9. </li></ul><ul><li>Complement proteins c...
Complement Fixation <ul><li>Complement proteins attach to the cell membrane and destroy it. </li></ul><ul><li>Antibodies o...
Complement Fixation <ul><li>C2 a  attaches to C4 b  and cleaves C3 into C3 a  and C3 b .  </li></ul><ul><li>Fragment C3 b ...
Complement Fixation <ul><li>Complement proteins C5 to C9 create large pores in membrane, causing osmotic influx of H 2 0. ...
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Complement Fragments <ul><li>Complement fragments: </li></ul><ul><ul><li>Chemotaxis:  </li></ul></ul><ul><ul><ul><li>Attra...
Interferon <ul><li>Interferons (cytokines) </li></ul><ul><ul><li>Nonspecific, short-acting resistance to viruses. </li></u...
Fever <ul><li>Third major kind of nonspecific cellular and chemical defense. </li></ul><ul><li>Hypothalamus regulates body...
Nonspecific Immunity <ul><li>Endogenous pyrogens: </li></ul><ul><li>Cell wall of gram – bacteria contains endotoxin. </li>...
Adaptive (Specific) Immunity <ul><li>General Information </li></ul><ul><ul><li>Third line of defense: the immune response ...
Adaptive (Specific) Immunity <ul><li>Two aspects: </li></ul><ul><ul><li>Humoral and Cell-mediated </li></ul></ul><ul><ul><...
Adaptive (Specific) Immunity <ul><li>Two aspects: continued </li></ul><ul><ul><li>Cell-mediated immunity </li></ul></ul><u...
Adaptive (Specific) Immunity <ul><li>Requires prior exposure </li></ul><ul><ul><li>Can be through immunization </li></ul><...
Antigens <ul><li>Molecules that stimulate the production of antibodies. </li></ul><ul><li>Combine specifically with antibo...
Haptens <ul><li>Small organic molecules can become antigens if they bind to proteins. </li></ul><ul><li>Become antigenic d...
Immunoassays <ul><li>Antigen-antibody complex reaction can produce clumping (agglutination). </li></ul><ul><li>Agglutinate...
Lymphocytes <ul><li>Derived from stem cells in the bone marrow. </li></ul><ul><li>Stem cells produce the specialized blood...
Lymphocytes <ul><li>Lymphocytes that seed the thymus become T lymphocytes (T cells). </li></ul><ul><li>Have surface charac...
Lymphocytes <ul><li>Most of the lymphocytes that are not T cells are B lymphocytes (B cells). </li></ul><ul><li>Processed ...
B Lymphocytes <ul><li>Secrete antibodies that bind to antigens. </li></ul><ul><li>Stimulate production of memory cells: </...
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Antibodies <ul><li>Antibody proteins are also known as immunoglobulins. </li></ul><ul><li>Found in the gamma globulin clas...
Antibodies  www.freelivedoctor.com Immunoglobulin Functions lgG Main form of antibodies in circulation: production increas...
Antibody Structure  <ul><li>100 million trillion antibody molecules that contain 4 polypeptide chains. </li></ul><ul><li>F...
Active Immunity <ul><li>Primary response: </li></ul><ul><ul><li>First exposure to pathogen, immune response insufficient t...
Active Immunity <ul><li>Secondary response: </li></ul><ul><li>Subsequent exposure to same antigen. </li></ul><ul><li>Antib...
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Clonal Selection Theory <ul><li>B lymphocytes inherit the ability to produce a particular antibody. </li></ul><ul><li>T ly...
Clonal Selection Theory <ul><li>Exposure stimulates specific lymphocytes to divide many times until a large population of ...
Passive Immunity <ul><li>Immune protection produced by the transfer of antibodies to a recipient from a donor. </li></ul><...
Passive Immunity <ul><li>Immunological competence: </li></ul><ul><ul><li>Ability to mount a specific immune response. </li...
Monoclonal Antibodies <ul><li>Commercially prepared. </li></ul><ul><li>Exhibit specificity for one antigenic determinant o...
T Lymphocytes <ul><li>Thymus atrophies after puberty. </li></ul><ul><li>Colonies of T cells in lymph nodes and other organ...
Killer (cytotoxic) T Cells <ul><li>Cell mediated destruction. </li></ul><ul><li>Destroy specific cells with antigens on th...
Helper T Cells <ul><li>Indirectly participate by regulating the response of both T killer cells and B cells. </li></ul><ul...
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Suppressor T Cells <ul><li>Indirectly participate in the specific immune response. </li></ul><ul><li>Inhibit T cell and B ...
Lymphokines <ul><li>Interleukin-1: </li></ul><ul><ul><li>Secreted by macrophages and other cells. </li></ul></ul><ul><ul><...
Subtypes of Helper T Cells <ul><li>T H 1: </li></ul><ul><ul><li>Produce interleukin 2 and gamma interferon. </li></ul></ul...
Major Histocompatability Complexes (MHC) <ul><li>All cells except mature RBCs are genetically marked with histocompatabili...
Major Histocompatability Complexes <ul><li>MHC-class-1: </li></ul><ul><ul><li>Produced by all cells but RBCs. </li></ul></...
Major Histocompatability Complexes <ul><li>MHC-class-2: </li></ul><ul><ul><li>Produced only on antigen-presenting cells an...
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Destruction of T Lymphocytes <ul><li>Activated T cells must be destroyed after the infection has cleared. </li></ul><ul><l...
Tumor Immunology <ul><li>Tumors are interrelated with the functions of the immune system. </li></ul><ul><li>Division of tu...
Immunotherapy for Cancer <ul><li>Interleukin-2 activates both killer T cells and B lymphocytes. </li></ul><ul><li>Gamma in...
Diseases Caused by the Immune System <ul><li>Ability of immune system to tolerate self-antigens while it identifies and at...
Autoimmunity <ul><li>Those produced by failure in the immune system to recognize and tolerate self-antigens. </li></ul><ul...
Autoimmunity <ul><li>Antibodies may be produced that are directed against other antibodies. </li></ul><ul><ul><li>Rheumato...
Immune Complex Diseases <ul><li>Antigen-antibody combinations that are free rather than attached to bacterial or other cel...
Immediate Hypersensitivity <ul><li>Production of IgE antibodies. </li></ul><ul><li>Do not circulate in the blood. </li></u...
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Immunity

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Immunity

  1. 1. The Immune System Chapter 15 www.freelivedoctor.com
  2. 2. Defense Mechanisms <ul><li>The Immune system </li></ul><ul><ul><li>All structures and processes that provide a defense against pathogens. </li></ul></ul><ul><ul><ul><li>Pathogen: a disease-causing agent </li></ul></ul></ul><ul><ul><li>Is a functional system </li></ul></ul><ul><ul><ul><li>Includes cells that carry out immune defense </li></ul></ul></ul><ul><ul><ul><ul><li>Trillions of cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Inhabit lymphatic tissue </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Circulate in body fluid </li></ul></ul></ul></ul><ul><ul><ul><li>Most important </li></ul></ul></ul><ul><ul><ul><ul><li>Lymphocytes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>macrophages </li></ul></ul></ul></ul>www.freelivedoctor.com
  3. 3. Defense Mechanisms <ul><li>Immune defenses identify self from non-self </li></ul><ul><ul><li>Protect against microbes </li></ul></ul><ul><ul><ul><li>Viruses </li></ul></ul></ul><ul><ul><ul><li>Bacteria </li></ul></ul></ul><ul><ul><ul><li>Fungi </li></ul></ul></ul><ul><ul><ul><li>Parasites </li></ul></ul></ul><ul><ul><li>Isolate or remove nonmicrobial foreign substances </li></ul></ul><ul><ul><li>Destroy cancer cells </li></ul></ul><ul><li>Function is called Immune surveillance </li></ul>www.freelivedoctor.com
  4. 4. Defense Mechanisms <ul><li>Immunology </li></ul><ul><ul><li>Study of physiological defenses by which the host destroys or neutralizes foreign matter </li></ul></ul><ul><ul><ul><li>Both dead and living foreign matter </li></ul></ul></ul><ul><li>Immunity: also called immune defenses </li></ul><ul><ul><li>Nonspecific or innate: </li></ul></ul><ul><ul><ul><li>Inherited defense mechanisms. </li></ul></ul></ul><ul><ul><li>Specific or acquired: </li></ul></ul><ul><ul><ul><li>Prior exposure (lymphocytes). </li></ul></ul></ul>www.freelivedoctor.com
  5. 5. Immunity <ul><li>Nonspecific immunity </li></ul><ul><ul><li>Characteristics </li></ul></ul><ul><ul><ul><li>Can respond immediately to protect against any foreign substance or cell </li></ul></ul></ul><ul><ul><ul><li>Does not have to recognize specific identity </li></ul></ul></ul><ul><ul><ul><li>Is genetic </li></ul></ul></ul><ul><li>Specific Immunity </li></ul><ul><ul><li>Characteristics: </li></ul></ul><ul><ul><ul><li>Depends upon specific recognition </li></ul></ul></ul><ul><ul><ul><ul><li>By lymphocytes </li></ul></ul></ul></ul><ul><ul><ul><li>Attack is unique to the substance or cell </li></ul></ul></ul><ul><li>Work together: </li></ul><ul><ul><li>Nonspecific “sets the stage for specific </li></ul></ul>www.freelivedoctor.com
  6. 6. The Players <ul><li>Cells </li></ul><ul><ul><li>All leukocytes </li></ul></ul><ul><ul><li>Notable derivatives or relations </li></ul></ul><ul><ul><ul><li>Plasma cells </li></ul></ul></ul><ul><ul><ul><li>Macrophages </li></ul></ul></ul><ul><ul><ul><li>Macrophage-like cells (not descended from macrophages) </li></ul></ul></ul><ul><ul><ul><li>Mast cells </li></ul></ul></ul>www.freelivedoctor.com
  7. 7. The Players <ul><li>Chemicals </li></ul><ul><ul><li>Cytokines </li></ul></ul><ul><ul><ul><li>Protein messengers released from cells </li></ul></ul></ul><ul><ul><ul><ul><li>Regulate cell growth and development in both nonspecific and specific defenses </li></ul></ul></ul></ul><ul><ul><ul><li>Act as paracrine agents mostly </li></ul></ul></ul><ul><ul><ul><li>Sometimes have hormone effects </li></ul></ul></ul><ul><ul><ul><ul><li>Circulate in blood </li></ul></ul></ul></ul><ul><ul><ul><li>Physiology is complex </li></ul></ul></ul>www.freelivedoctor.com
  8. 8. Nonspecific Immunity <ul><li>General information: </li></ul><ul><ul><li>Also called nonspecific body defenses </li></ul></ul><ul><ul><li>Includes: </li></ul></ul><ul><ul><ul><li>Membrane barriers </li></ul></ul></ul><ul><ul><ul><li>Array of cells and chemicals on initial “battlefronts” </li></ul></ul></ul><ul><ul><li>Species resistance: inherited nonspecific resistance </li></ul></ul>www.freelivedoctor.com
  9. 9. Nonspecific Immunity: MB <ul><li>Surface Membrane Barriers </li></ul><ul><li>First Line of Defense </li></ul><ul><ul><li>Intact epithelial barriers </li></ul></ul><ul><ul><li>Are physical barriers </li></ul></ul><ul><li>External: epithelial membranes </li></ul><ul><ul><li>Skin. (cutaneous membrane) </li></ul></ul><ul><ul><ul><li>Keratin </li></ul></ul></ul><ul><ul><ul><ul><li>Resist weak acids and bases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Resist bacterial enzymes and toxins </li></ul></ul></ul></ul><ul><ul><li>Mucous membranes: </li></ul></ul><ul><ul><ul><li>Outer surface of eye </li></ul></ul></ul><ul><ul><ul><li>Lines exterior-exposed body cavities </li></ul></ul></ul><ul><ul><ul><ul><li>GI tract. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Respiratory tract. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Urinary tract. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Reproductive tract. </li></ul></ul></ul></ul>www.freelivedoctor.com
  10. 10. Nonspecific Immunity: MB <ul><li>Protective Chemicals </li></ul><ul><ul><li>Acid pH of skin secretions </li></ul></ul><ul><ul><ul><li>Decrease bacterial growth </li></ul></ul></ul><ul><ul><ul><li>SEBUM: contains chemicals toxic to bacteria </li></ul></ul></ul><ul><ul><ul><li>Vaginal secretion: very acidic </li></ul></ul></ul><ul><ul><li>Stomach mucosa: secretions kill pathogens </li></ul></ul><ul><ul><ul><li>HCL </li></ul></ul></ul><ul><ul><ul><li>Pepsin </li></ul></ul></ul><ul><ul><li>Saliva: washes oral cavity and teeth </li></ul></ul><ul><ul><ul><li>Contains LYSOZYME: kills bacteria </li></ul></ul></ul><ul><ul><li>Lacrimal fluid: washes external eye surface </li></ul></ul><ul><ul><ul><li>Contains LYSOZYME </li></ul></ul></ul><ul><ul><li>Mucus </li></ul></ul><ul><ul><ul><li>Traps microorganisms (sticky) </li></ul></ul></ul><ul><li>Other Protective devices </li></ul><ul><ul><li>cilia </li></ul></ul>www.freelivedoctor.com
  11. 11. Nonspecific Immunity: cells and chemicals <ul><li>OVERVIEW </li></ul><ul><li>Enormous number of cellular and chemical defenses </li></ul><ul><ul><li>Need way to distinguish self from nonself </li></ul></ul><ul><ul><li>Need general characteristic marking an invader </li></ul></ul><ul><li>Most common IDENTIY TAGS </li></ul><ul><ul><li>Classes of carbohydrate and lipid in bacterial cell walls </li></ul></ul><ul><ul><li>Can be recognized by immune cells and defense plasma proteins (eg: complement) </li></ul></ul><ul><ul><ul><li>Bind to invaders </li></ul></ul></ul><ul><ul><li>Key difference between specific and nonspecific defense </li></ul></ul>www.freelivedoctor.com
  12. 12. Nonspecific Immunity: cells and chemicals <ul><li>OVERVIEW: continued </li></ul><ul><li>Most significant methods: </li></ul><ul><ul><li>Phagocytosis and Natural killer cells </li></ul></ul><ul><ul><li>Inflammatory Response </li></ul></ul><ul><ul><ul><li>Cells enlisted: </li></ul></ul></ul><ul><ul><ul><ul><li>Macrophages </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mast cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>WBCs in general </li></ul></ul></ul></ul><ul><ul><ul><li>Many kinds of chemicals </li></ul></ul></ul><ul><ul><ul><ul><li>Some help kill pathogens </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Some help repair tissues </li></ul></ul></ul></ul>www.freelivedoctor.com
  13. 13. Nonspecific Immunity: cells and chemicals <ul><li>OVERVIEW: continued </li></ul><ul><ul><li>Antimicrobial Substances </li></ul></ul><ul><ul><ul><li>Antibacterial proteins </li></ul></ul></ul><ul><ul><ul><ul><li>Called COMPLEMENT: mostly made by hepatocytes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>in blood </li></ul></ul></ul></ul><ul><ul><ul><li>Antiviral proteins </li></ul></ul></ul><ul><ul><ul><ul><li>Called INTERFERON </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Released by virus-infected cells </li></ul></ul></ul></ul><ul><ul><li>Fever: </li></ul></ul><ul><ul><ul><li>Systemic response. </li></ul></ul></ul><ul><ul><ul><li>High temperature: </li></ul></ul></ul><ul><ul><ul><ul><li>Inhibits microbial replication. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Enhances body repair. </li></ul></ul></ul></ul>www.freelivedoctor.com
  14. 14. Nonspecific Immunity: cells and chemicals <ul><li>Phagocytosis: ingestion and destruction of particulate matter </li></ul><ul><ul><li>One of most important nonspecific defenses </li></ul></ul><ul><li>Based on ability to distinguish between the kinds of carbohydrates that are produced by mammalian cells and those produced by bacteria. </li></ul><ul><ul><li>Bacterial carbohydrates flag the cell for phagocytic attack. </li></ul></ul><ul><li>3 major groups of phagocytic cells: </li></ul><ul><ul><li>Neutrophils: 1 st to arrive at infection. </li></ul></ul><ul><ul><li>Mononuclear phagocyte system: </li></ul></ul><ul><ul><ul><li>Macrophages and monocytes. </li></ul></ul></ul><ul><ul><li>Organ-specific phagocytes. </li></ul></ul><ul><ul><ul><li>Kupffer cells </li></ul></ul></ul><ul><ul><ul><li>Langerhans cells </li></ul></ul></ul><ul><ul><ul><li>Histiocytes </li></ul></ul></ul>www.freelivedoctor.com
  15. 15. Phagocytosis <ul><li>Method of Action </li></ul><ul><ul><li>Ingestion </li></ul></ul><ul><ul><ul><li>Form PHAGOSOME </li></ul></ul></ul><ul><ul><ul><li>Fuse with lysosome </li></ul></ul></ul><ul><ul><ul><li>NOT ALWAYS SUCCESSFUL </li></ul></ul></ul><ul><ul><ul><ul><li>Must adhere first </li></ul></ul></ul></ul><ul><ul><ul><ul><li>“ Rougher” the surface the better </li></ul></ul></ul></ul><ul><ul><ul><ul><li>“ Roughened” by: </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Complement proteins </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>antibodies </li></ul></ul></ul></ul></ul>www.freelivedoctor.com
  16. 16. Phagocytosis <ul><li>Neutrophils and monocytes are able to squeeze through tiny gaps between adjacent endothelial cells. </li></ul>www.freelivedoctor.com
  17. 17. Phagocytosis <ul><li>Destruction </li></ul><ul><ul><li>By macrophages and neutrophils </li></ul></ul><ul><ul><li>Intracellular digestion </li></ul></ul><ul><ul><ul><li>Activate lysosomal enzymes </li></ul></ul></ul><ul><ul><ul><li>Produce RESPIRATORY BURST </li></ul></ul></ul><ul><ul><ul><ul><li>Liberates free radicals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Potent cell-killing abilities </li></ul></ul></ul></ul><ul><ul><li>Extracellular Destruction </li></ul></ul><ul><ul><ul><li>Neutrophils </li></ul></ul></ul><ul><ul><ul><li>Release oxidizing substances </li></ul></ul></ul><ul><ul><ul><li>Effectively kills cells </li></ul></ul></ul><ul><ul><ul><ul><li>Also kills neutrophils </li></ul></ul></ul></ul><ul><ul><ul><ul><li>May damage tissue cells </li></ul></ul></ul></ul>www.freelivedoctor.com
  18. 18. Phagocytosis <ul><li>Phagocytes engulf particles similar to amoeba. </li></ul><ul><ul><li>Particle becomes surrounded by pseudopods. </li></ul></ul><ul><ul><li>Forms vacuole. </li></ul></ul><ul><ul><li>Vacuole fuses with lysosomes which digest the particle. </li></ul></ul><ul><ul><li>Lysosomes can be released into the infected area. </li></ul></ul>www.freelivedoctor.com
  19. 19. Phagocytes Intracellular killing of microbes Regulate inflammation Extracellular killing Activation of clotting or anti-clotting Hormonal regulation Chemical secretion www.freelivedoctor.com
  20. 20. Natural Killer (NK) Cells <ul><li>Lymphocytes that are related to T cells. </li></ul><ul><li>Do not need specific antigen recognition </li></ul><ul><ul><li>Do not require prior exposure for sensitization to the tumor antigens </li></ul></ul><ul><ul><li>NK cells destroy tumors in a nonspecific fashion. </li></ul></ul><ul><li>Roam body in blood and lymph </li></ul><ul><li>Method of action: </li></ul><ul><ul><li>Lysis of cancer cells </li></ul></ul><ul><ul><li>Lysis of viras-infected body cells </li></ul></ul><ul><li>Act before Immune Response </li></ul><ul><ul><li>Provide first line of cell-mediated defense. </li></ul></ul><ul><ul><li>Stimulated by interferon. </li></ul></ul>www.freelivedoctor.com
  21. 21. Inflammatory Response <ul><li>Second major kind of nonspecific cellular and chemical defense </li></ul><ul><ul><li>Considered second line of defense </li></ul></ul><ul><ul><ul><li>Involves interaction of cells, chemicals and tissue fluid </li></ul></ul></ul><ul><ul><li>Occurs when: </li></ul></ul><ul><ul><ul><li>Surface barriers are breached </li></ul></ul></ul><ul><ul><ul><li>Tissues are injured by physical factors </li></ul></ul></ul><ul><ul><ul><ul><li>Heat/cold </li></ul></ul></ul></ul><ul><ul><ul><ul><li>UV radiation </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Ionizing radiation (x-rays) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Physical trauma </li></ul></ul></ul></ul>www.freelivedoctor.com
  22. 22. Inflammatory Response <ul><li>Principle effects </li></ul><ul><ul><li>Prevents spread of injurious agent </li></ul></ul><ul><ul><li>Disposes of cellular debris and pathogens </li></ul></ul><ul><ul><li>Sets stage for repair </li></ul></ul><ul><li>Acute inflammation </li></ul><ul><ul><li>Short term </li></ul></ul><ul><ul><li>4 cardinal signs </li></ul></ul><ul><ul><ul><li>Swelling </li></ul></ul></ul><ul><ul><ul><li>Redness </li></ul></ul></ul><ul><ul><ul><li>Heat </li></ul></ul></ul><ul><ul><ul><li>pain </li></ul></ul></ul>www.freelivedoctor.com
  23. 23. Local Inflammation <ul><li>Inflammatory reaction initiated by phagocytosis and complement activation. </li></ul><ul><li>Complement activation attracts new phagocytes to the area. </li></ul><ul><li>B lymphocytes are stimulated to produce antibodies against specific antigens. </li></ul><ul><ul><li>Activates complement. </li></ul></ul><ul><ul><li>Antibodies promote phagocytic activity. </li></ul></ul>www.freelivedoctor.com
  24. 24. Local Inflammation <ul><li>Leukocytes interact with adhesion molecules in endothelial cell. </li></ul><ul><li>Chemotaxis attracts leukocytes. </li></ul><ul><li>Via diapedesis, leukocytes guide more leukocytes to site of infection. </li></ul><ul><li>First to arrive are neutrophils, then monocytes, and T lymphocytes. </li></ul>www.freelivedoctor.com
  25. 25. Local Inflammation <ul><li>Mast cells release histamine and secrete TNF-alpha. </li></ul><ul><ul><li>Increases membrane permeability. </li></ul></ul><ul><ul><li>Vasodilation. </li></ul></ul><ul><ul><li>Recruit neutrophils. </li></ul></ul>www.freelivedoctor.com
  26. 26. Local Inflammation <ul><li>Characteristic effects of inflammation: </li></ul><ul><ul><li>Redness and warmth. </li></ul></ul><ul><ul><li>Swelling (edema). </li></ul></ul><ul><ul><li>Pus (dead leukocytes). </li></ul></ul><ul><ul><li>Pain. </li></ul></ul><ul><ul><li>Endogenous pyrogens. </li></ul></ul>www.freelivedoctor.com
  27. 27. Antimicrobial Substances <ul><li>Third major kind of nonspecific cellular and chemical defense </li></ul><ul><li>Includes complement and interferon </li></ul><ul><li>Considered a second line of defense </li></ul>www.freelivedoctor.com
  28. 28. Complement <ul><li>Also called the complement system </li></ul><ul><li>General points </li></ul><ul><ul><li>Group of ~ 20 plasma proteins </li></ul></ul><ul><ul><li>Usually inactive </li></ul></ul><ul><ul><li>Major system to destroy foreign substances </li></ul></ul><ul><ul><li>Nonspecific </li></ul></ul><ul><ul><li>Works with and overlays other methods of defense </li></ul></ul>www.freelivedoctor.com
  29. 29. Complement Proteins <ul><li>Complements (or enhances) nonspecific and specific defenses. </li></ul><ul><li>The combination of antibodies with antigens does not cause destruction of the antigens or pathogen. </li></ul><ul><li>Antibodies serve to identify the targets for immunological attack. </li></ul><ul><li>Identified antibodies activate the complement against specific invaders. </li></ul>www.freelivedoctor.com
  30. 30. Activated Complement Proteins Direct destruction by MAC (membrane attack complex) Vasodilation Increased capillary permeability Chemotaxis Opsinization (antibodies stimulate phagocytosis) www.freelivedoctor.com
  31. 31. <ul><li>Two major pathways. </li></ul><ul><li>Classical : </li></ul><ul><ul><li>11 proteins </li></ul></ul><ul><ul><ul><li>C1 – C9 </li></ul></ul></ul><ul><ul><ul><ul><li>C1 actually 3 protein </li></ul></ul></ul></ul><ul><ul><li>Initiation </li></ul></ul><ul><ul><ul><li>Antibodies bind to pathogen </li></ul></ul></ul><ul><ul><ul><li>C1 binds to AP complex </li></ul></ul></ul><ul><ul><ul><li>Complement activated in sequence. </li></ul></ul></ul><ul><li>Alternate Pathway </li></ul><ul><ul><li>Triggered by interaction of 3 plasma proteins </li></ul></ul><ul><ul><ul><li>Factors B, D, and P </li></ul></ul></ul><ul><ul><ul><li>These interact with carbos on cell surface of </li></ul></ul></ul><ul><ul><ul><ul><li>Bacteria </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Parasites </li></ul></ul></ul></ul><ul><ul><ul><ul><li>fungi </li></ul></ul></ul></ul>Complement Types www.freelivedoctor.com
  32. 32. <ul><li>Classical </li></ul><ul><li>11 complement proteins, designated C-1 to C-9. </li></ul><ul><li>Complement proteins can be subdivided into 3 components: </li></ul><ul><ul><li>C1: recognization. </li></ul></ul><ul><ul><li>C4, C2, C3: activation. </li></ul></ul><ul><ul><li>C5-C9: attack (complement fixation). </li></ul></ul>Complement Types www.freelivedoctor.com
  33. 33. Complement Fixation <ul><li>Complement proteins attach to the cell membrane and destroy it. </li></ul><ul><li>Antibodies of IgG and IgM attach to antigens on invading cell membranes, bind to C1 activating the process. </li></ul><ul><li>Activated C1 hydrolyzes C4 into C4 a and C4 b . </li></ul><ul><li>C4 b binds to the cell membrane. </li></ul><ul><li>C4 b splits C2 into C2 a and C2 b . </li></ul>www.freelivedoctor.com
  34. 34. Complement Fixation <ul><li>C2 a attaches to C4 b and cleaves C3 into C3 a and C3 b . </li></ul><ul><li>Fragment C3 b becomes attached to the complex in the cell membrane. </li></ul><ul><li>C3 b converts C5 to C5 a and C5 b . </li></ul><ul><li>C5 b and C6 through C9 become fixed to the cell membrane. </li></ul>www.freelivedoctor.com
  35. 35. Complement Fixation <ul><li>Complement proteins C5 to C9 create large pores in membrane, causing osmotic influx of H 2 0. </li></ul><ul><li>Complement proteins kill the cell. </li></ul>www.freelivedoctor.com
  36. 36. www.freelivedoctor.com
  37. 37. Complement Fragments <ul><li>Complement fragments: </li></ul><ul><ul><li>Chemotaxis: </li></ul></ul><ul><ul><ul><li>Attract phagocytes. </li></ul></ul></ul><ul><ul><li>Opsinization: </li></ul></ul><ul><ul><ul><li>Phagocytes have receptors for C3 b . </li></ul></ul></ul><ul><ul><ul><li>Form bridges between phagocyte and victim cell. </li></ul></ul></ul><ul><ul><li>Histamine release: </li></ul></ul><ul><ul><ul><li>Increase blood flow and capillary permeability. </li></ul></ul></ul><ul><ul><ul><li>Bring in more phagocytes. </li></ul></ul></ul>www.freelivedoctor.com
  38. 38. Interferon <ul><li>Interferons (cytokines) </li></ul><ul><ul><li>Nonspecific, short-acting resistance to viruses. </li></ul></ul><ul><ul><li>Act as messengers that protect other cells in the vicinity from viral infection. </li></ul></ul><ul><ul><li>Produced by most body cells </li></ul></ul><ul><ul><ul><li> inhibit viral replication, increases NK cells, induces MHC-I antigens. </li></ul></ul></ul><ul><ul><ul><li> inhibit viral replication, increases NK cells, induces MHC-I antigens. </li></ul></ul></ul><ul><ul><li>Produced by  certain lymphocytes, NK cells </li></ul></ul><ul><ul><ul><li> activates macrophages, induces MHC-II antigens. </li></ul></ul></ul><ul><ul><ul><li>Defense against infection and cancer </li></ul></ul></ul>www.freelivedoctor.com
  39. 39. Fever <ul><li>Third major kind of nonspecific cellular and chemical defense. </li></ul><ul><li>Hypothalamus regulates body temp </li></ul><ul><ul><li>Thermoregulatory center. </li></ul></ul><ul><li>Reset upward by endogenous pyrogen </li></ul><ul><ul><li>May be interleukin-1 beta </li></ul></ul><ul><ul><ul><li>First produced as a cytokine by WBCs </li></ul></ul></ul><ul><ul><ul><li>Then produced by the brain. </li></ul></ul></ul>www.freelivedoctor.com
  40. 40. Nonspecific Immunity <ul><li>Endogenous pyrogens: </li></ul><ul><li>Cell wall of gram – bacteria contains endotoxin. </li></ul><ul><li>Endotoxin stimulates monocytes and macrophages to release cytokines: </li></ul><ul><ul><li>Interleukin-1, interleukin-2, TNF (tumor necrosis factor): </li></ul></ul><ul><ul><li>Increased activity of neutrophils. </li></ul></ul><ul><ul><li>Increased production of interferon. </li></ul></ul><ul><ul><li>Produce fever, increase sleepiness, and decrease plasma iron. </li></ul></ul>www.freelivedoctor.com
  41. 41. Adaptive (Specific) Immunity <ul><li>General Information </li></ul><ul><ul><li>Third line of defense: the immune response </li></ul></ul><ul><ul><li>Functions: </li></ul></ul><ul><ul><ul><li>Amplify the inflammatory response </li></ul></ul></ul><ul><ul><ul><li>Activate complement </li></ul></ul></ul><ul><ul><ul><li>Specific defense against specific antigens </li></ul></ul></ul><ul><ul><ul><li>Adaptive defense </li></ul></ul></ul><ul><ul><ul><li>Has memory </li></ul></ul></ul>www.freelivedoctor.com
  42. 42. Adaptive (Specific) Immunity <ul><li>Two aspects: </li></ul><ul><ul><li>Humoral and Cell-mediated </li></ul></ul><ul><ul><li>Humoral Immunity </li></ul></ul><ul><ul><ul><li>Involves B-cells </li></ul></ul></ul><ul><ul><ul><ul><li>Produce antibodies </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Kinds </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Plasma cells </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Memory cells </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Attack: </li></ul></ul></ul><ul><ul><ul><ul><li>Bacteria </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Free viruses </li></ul></ul></ul></ul>www.freelivedoctor.com
  43. 43. Adaptive (Specific) Immunity <ul><li>Two aspects: continued </li></ul><ul><ul><li>Cell-mediated immunity </li></ul></ul><ul><ul><ul><li>Involves T-cells </li></ul></ul></ul><ul><ul><ul><ul><li>Direct cellular attack </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Also release chemical mediators </li></ul></ul></ul></ul><ul><ul><ul><li>Kinds </li></ul></ul></ul><ul><ul><ul><ul><li>Regulatory cells </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Helper T (2 kinds) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Suppressor T </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Effector cell </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Cytotoxic T </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Memory T </li></ul></ul></ul></ul><ul><ul><ul><li>Attack </li></ul></ul></ul><ul><ul><ul><ul><li>Cells infected with viruses, intracellular parasites </li></ul></ul></ul></ul>www.freelivedoctor.com
  44. 44. Adaptive (Specific) Immunity <ul><li>Requires prior exposure </li></ul><ul><ul><li>Can be through immunization </li></ul></ul><ul><li>Results in the production of antibodies </li></ul><ul><ul><li>Responsible for the immunity </li></ul></ul><ul><ul><li>Are specific in action </li></ul></ul><ul><ul><li>Produced by B-lymphocytes </li></ul></ul><ul><ul><li>Produced in response to antigens </li></ul></ul>www.freelivedoctor.com
  45. 45. Antigens <ul><li>Molecules that stimulate the production of antibodies. </li></ul><ul><li>Combine specifically with antibodies produced. </li></ul><ul><li>Foreign to blood and other body fluids. </li></ul><ul><li>Immune system can distinguish “self” molecules from nonself antigens. </li></ul><ul><li>Large, complex molecules can have different antigenic determinant sites. </li></ul>www.freelivedoctor.com
  46. 46. Haptens <ul><li>Small organic molecules can become antigens if they bind to proteins. </li></ul><ul><li>Become antigenic determinant sites on the proteins. </li></ul>www.freelivedoctor.com
  47. 47. Immunoassays <ul><li>Antigen-antibody complex reaction can produce clumping (agglutination). </li></ul><ul><li>Agglutinated particles can be used to assay a variety of antigens. </li></ul>www.freelivedoctor.com
  48. 48. Lymphocytes <ul><li>Derived from stem cells in the bone marrow. </li></ul><ul><li>Stem cells produce the specialized blood cells. </li></ul><ul><li>Replace themselves by cell division so the stem cell population is not depleted. </li></ul><ul><li>Lymphocytes seed the thymus, spleen, and lymph nodes. </li></ul>www.freelivedoctor.com
  49. 49. Lymphocytes <ul><li>Lymphocytes that seed the thymus become T lymphocytes (T cells). </li></ul><ul><li>Have surface characteristics and immunological function that differ from other lymphocytes. </li></ul><ul><li>Do not secrete antibodies. </li></ul><ul><li>Must come in close or direct contact to destroy them. </li></ul><ul><li>T cells are 65 – 85% of the lymphocytes in blood and most in the germinal centers of lymph nodes and spleen. </li></ul>www.freelivedoctor.com
  50. 50. Lymphocytes <ul><li>Most of the lymphocytes that are not T cells are B lymphocytes (B cells). </li></ul><ul><li>Processed in the bone marrow. </li></ul><ul><li>Function in specific immunity. </li></ul><ul><li>B cells combat bacterial infections as well as some viral infections by secreting antibodies into the blood and lymph. </li></ul><ul><li>Provide humoral immunity (blood and lymph are body fluids (humors). </li></ul>www.freelivedoctor.com
  51. 51. B Lymphocytes <ul><li>Secrete antibodies that bind to antigens. </li></ul><ul><li>Stimulate production of memory cells: </li></ul><ul><ul><li>Important in active immunity. </li></ul></ul><ul><li>Others are transformed into plasma cells: </li></ul><ul><ul><li>Produce 2000 antibody proteins/sec when exposed to antigen. </li></ul></ul><ul><ul><li>These antigens may be isolated molecules or may be molecules at the surface of an invading foreign cell. </li></ul></ul>www.freelivedoctor.com
  52. 52. www.freelivedoctor.com
  53. 53. Antibodies <ul><li>Antibody proteins are also known as immunoglobulins. </li></ul><ul><li>Found in the gamma globulin class of plasma proteins. </li></ul><ul><li>Different antibodies have different structure, as the antibodies have specific actions. </li></ul>www.freelivedoctor.com
  54. 54. Antibodies www.freelivedoctor.com Immunoglobulin Functions lgG Main form of antibodies in circulation: production increased after immunization; secreted during secondary response lgA Main antibody type in external secretions, such as saliva and mother’s milk lgE Responsible for allergic symptoms in immediate hypersensitivity reactions lgM Function as antigen receptors on lymphocyte surface prior to immunization; secreted during primary response lgD Function as antigen receptors on lymphocyte surface prior to immunization; other functions unknown
  55. 55. Antibody Structure <ul><li>100 million trillion antibody molecules that contain 4 polypeptide chains. </li></ul><ul><li>F ab regions are variable, provide a specific bonding site for antigen. </li></ul><ul><li>B lymphocytes have antibodies that serve as receptors for antigens </li></ul><ul><li>Provides active immunity. </li></ul>www.freelivedoctor.com
  56. 56. Active Immunity <ul><li>Primary response: </li></ul><ul><ul><li>First exposure to pathogen, immune response insufficient to combat disease. </li></ul></ul><ul><ul><li>Latent period of 5-10 days before measurable amounts of specific antibodies appear in blood. </li></ul></ul>www.freelivedoctor.com
  57. 57. Active Immunity <ul><li>Secondary response: </li></ul><ul><li>Subsequent exposure to same antigen. </li></ul><ul><li>Antibody production is much more rapid. </li></ul><ul><ul><li>Maximum antibody concentration reached in < 2 hrs. </li></ul></ul><ul><ul><li>Maintained longer period of time. </li></ul></ul>www.freelivedoctor.com
  58. 58. www.freelivedoctor.com
  59. 59. Clonal Selection Theory <ul><li>B lymphocytes inherit the ability to produce a particular antibody. </li></ul><ul><li>T lymphocytes inherit the ability to respond to particular antigens. </li></ul><ul><li>Inherited specificity reflected in antigen receptor proteins on surface of lymphocytes. </li></ul>www.freelivedoctor.com
  60. 60. Clonal Selection Theory <ul><li>Exposure stimulates specific lymphocytes to divide many times until a large population of genetically identical cells (clone) is produced. </li></ul><ul><li>Antigens select lymphocytes that are already able to make antibodies. </li></ul>www.freelivedoctor.com
  61. 61. Passive Immunity <ul><li>Immune protection produced by the transfer of antibodies to a recipient from a donor. </li></ul><ul><li>Donor has been actively immunized. </li></ul><ul><li>Occurs naturally in mother to fetus during pregnancy and mother to infant during nursing. </li></ul>www.freelivedoctor.com
  62. 62. Passive Immunity <ul><li>Immunological competence: </li></ul><ul><ul><li>Ability to mount a specific immune response. </li></ul></ul><ul><ul><li>Does not develop until 1 month after birth. </li></ul></ul><ul><ul><li>Passive immunity disappears when infant is 1 month old. </li></ul></ul><ul><ul><ul><li>Infant did not itself produce lymphocyte clones. </li></ul></ul></ul>www.freelivedoctor.com
  63. 63. Monoclonal Antibodies <ul><li>Commercially prepared. </li></ul><ul><li>Exhibit specificity for one antigenic determinant only. </li></ul><ul><li>Results in more sophisticated clinical laboratory tests. </li></ul><ul><li>May aid in the diagnosis of cancer. </li></ul>www.freelivedoctor.com
  64. 64. T Lymphocytes <ul><li>Thymus atrophies after puberty. </li></ul><ul><li>Colonies of T cells in lymph nodes and other organs produce T cells under stimulation of thymus hormones. </li></ul><ul><li>Thymus secretes: </li></ul><ul><ul><li>Thymopoietin I and thymopoietin II </li></ul></ul><ul><ul><ul><li>Promote transformation of lymphocytes into T cells. </li></ul></ul></ul>www.freelivedoctor.com
  65. 65. Killer (cytotoxic) T Cells <ul><li>Cell mediated destruction. </li></ul><ul><li>Destroy specific cells with antigens on their surface. </li></ul><ul><li>Must be in actual contact with their victim cells. </li></ul><ul><li>Defend against viral and fungal infections. </li></ul><ul><li>Secrete perforins: </li></ul><ul><ul><li>Perforins polymerize in the cell membrane and form cylindrical channels through the membrane. </li></ul></ul>www.freelivedoctor.com
  66. 66. Helper T Cells <ul><li>Indirectly participate by regulating the response of both T killer cells and B cells. </li></ul><ul><li>B cells must be activated by helper T cells before they produce antibodies. </li></ul>www.freelivedoctor.com
  67. 67. www.freelivedoctor.com
  68. 68. Suppressor T Cells <ul><li>Indirectly participate in the specific immune response. </li></ul><ul><li>Inhibit T cell and B cell activities. </li></ul><ul><li>Affects the amount of antibodies secreted. </li></ul><ul><li>Moderate immune response. </li></ul>www.freelivedoctor.com
  69. 69. Lymphokines <ul><li>Interleukin-1: </li></ul><ul><ul><li>Secreted by macrophages and other cells. </li></ul></ul><ul><ul><li>Activates T cells. </li></ul></ul><ul><li>Interleukin-2: </li></ul><ul><ul><li>Released by helper T cells. </li></ul></ul><ul><ul><li>Activates killer T cells. </li></ul></ul><ul><li>Interleukin-3: </li></ul><ul><ul><li>Serves as a growth factor. </li></ul></ul><ul><ul><li>Activates killer T cells. </li></ul></ul><ul><li>Interleukin-4: </li></ul><ul><ul><li>Secreted by T cells. </li></ul></ul><ul><ul><li>Required for proliferation and clone development of B cells. </li></ul></ul>www.freelivedoctor.com
  70. 70. Subtypes of Helper T Cells <ul><li>T H 1: </li></ul><ul><ul><li>Produce interleukin 2 and gamma interferon. </li></ul></ul><ul><ul><ul><li>Activate killer T cells. </li></ul></ul></ul><ul><li>T H 2: </li></ul><ul><ul><li>Secrete interleukin-4 and interleukin-5. </li></ul></ul><ul><ul><ul><li>Stimulate B lymphocytes. </li></ul></ul></ul>www.freelivedoctor.com
  71. 71. Major Histocompatability Complexes (MHC) <ul><li>All cells except mature RBCs are genetically marked with histocompatability antigens on the membrane surface. </li></ul><ul><li>Also called human leukocyte antigens (HLAs). </li></ul><ul><li>The histocompatability antigens are coded for a group of genes called MHC located on chromosome 6. </li></ul><ul><li>MHC of genes produces 2 classes of MHC molecules: </li></ul><ul><ul><li>Class-1 </li></ul></ul><ul><ul><li>Class-2 </li></ul></ul>www.freelivedoctor.com
  72. 72. Major Histocompatability Complexes <ul><li>MHC-class-1: </li></ul><ul><ul><li>Produced by all cells but RBCs. </li></ul></ul><ul><ul><li>Picks up cytoplasmic peptides and transports to membrane. </li></ul></ul><ul><ul><li>Killer T cells (cytotoxic) interact with antigens. </li></ul></ul><ul><ul><li>Coreceptor CD8 permits each type of T cell to interact only with a specific class of MHC molecules. </li></ul></ul>www.freelivedoctor.com
  73. 73. Major Histocompatability Complexes <ul><li>MHC-class-2: </li></ul><ul><ul><li>Produced only on antigen-presenting cells and B cells </li></ul></ul><ul><ul><li>Appear only on cell membrane when cell is processing antigens. </li></ul></ul><ul><ul><li>Activate T cells. </li></ul></ul><ul><ul><li>Helper T cells react with antigens. </li></ul></ul><ul><ul><li>Coreceptor CD4 interact with only a specific class of MHC molecule. </li></ul></ul>www.freelivedoctor.com
  74. 74. www.freelivedoctor.com
  75. 75. Destruction of T Lymphocytes <ul><li>Activated T cells must be destroyed after the infection has cleared. </li></ul><ul><li>T cells produce a surface receptor called FAS. </li></ul><ul><li>Production of FAS increases during the infection. </li></ul><ul><li>Activated T cells begin to produce FAS ligand. </li></ul><ul><li>FAS binds to FAS ligand and triggers apoptosis (cell suicide). </li></ul>www.freelivedoctor.com
  76. 76. Tumor Immunology <ul><li>Tumors are interrelated with the functions of the immune system. </li></ul><ul><li>Division of tumor cells is not effectively controlled by normal inhibitory mechanisms. </li></ul><ul><li>Tumor cells also dedifferentiate (become similar to less specialized cells of an embryo). </li></ul><ul><li>As tumor cells dedifferentiate, they reveal surface antigens that can stimulate the immune destruction of the tumor. </li></ul>www.freelivedoctor.com
  77. 77. Immunotherapy for Cancer <ul><li>Interleukin-2 activates both killer T cells and B lymphocytes. </li></ul><ul><li>Gamma interferon are also used to treat cancer. </li></ul><ul><li>Preliminary results promising. </li></ul>www.freelivedoctor.com
  78. 78. Diseases Caused by the Immune System <ul><li>Ability of immune system to tolerate self-antigens while it identifies and attacks foreign antigens that can be deranged. </li></ul><ul><li>Diseases caused by the immune system can be grouped into 3 categories: </li></ul><ul><ul><li>Autoimmune disease. </li></ul></ul><ul><ul><li>Immune complex diseases. </li></ul></ul><ul><ul><li>Allergy or hypersensitivity. </li></ul></ul>www.freelivedoctor.com
  79. 79. Autoimmunity <ul><li>Those produced by failure in the immune system to recognize and tolerate self-antigens. </li></ul><ul><li>Failure due to: </li></ul><ul><ul><li>An antigen that does not normally circulate in the blood may be exposed to the immune system. </li></ul></ul><ul><ul><ul><li>Thyroglobulin. </li></ul></ul></ul><ul><ul><li>A self-antigen that is otherwise tolerated may be altered by combining with a foreign hapten. </li></ul></ul><ul><ul><ul><li>Thrombocytopenia. </li></ul></ul></ul>www.freelivedoctor.com
  80. 80. Autoimmunity <ul><li>Antibodies may be produced that are directed against other antibodies. </li></ul><ul><ul><li>Rheumatoid arthritis. </li></ul></ul><ul><li>Antibodies produced against foreign antigens may cross-react with self-antigens. </li></ul><ul><ul><li>Rheumatic fever. </li></ul></ul><ul><li>Self-antigens may be presented to the helper T cells together with class-2 MHC molecules. </li></ul><ul><ul><li>Type I diabetes. </li></ul></ul>www.freelivedoctor.com
  81. 81. Immune Complex Diseases <ul><li>Antigen-antibody combinations that are free rather than attached to bacterial or other cells. </li></ul><ul><li>Activates complement proteins and promotes inflammation. </li></ul><ul><ul><li>Hepatitis B. </li></ul></ul>www.freelivedoctor.com
  82. 82. Immediate Hypersensitivity <ul><li>Production of IgE antibodies. </li></ul><ul><li>Do not circulate in the blood. </li></ul><ul><li>Attach to mast cells and basophils. </li></ul><ul><li>When exposed again to same allergen, histamine and prostaglandin D are secreted. </li></ul><ul><li>Produce symptoms. </li></ul>www.freelivedoctor.com

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