ALS 2304 Animal Anatomy Final Exam: Immunity

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  1. Two Mechanisms of defense
    • 1. Nonspecific (innate) immunity
    • 2. Specific (acquired) immunity
  2. Nonspecific (innate) immunity
    • natural, nonspecific; essentially unregulated (i.e. always active)
    • Does not distinguish one threat from another
  3. Specific (acquired) immunity
    • specific, inducible, diverse, discriminatiory (self vs. non-self), self limiting, has "memory"
    • Turns on when a pathogen is detected.
    • Includes physical barriers, phagocytic cells, complement proteins, general inflammatory response and fever.
  4. What is included in the Specific immune system?
    • physical barriers
    • phagocytic cells
    • complement proteins
    • general inflammatory response ; fever
  5. What is the primary surface barrier?
    • skin, mucous membranes, secretions
    •      a. Stratified, desmosomes, keratinization.
    •           Hair fur
  6. How do secretions support the nonspecific immune system?
    • Secretions are acidic and contain bactericides, fatty acids, etc.
    • Saliva contains lysozyme-puts holes in bacteria
    • Mucous traps bacteria
  7. What is the role of mucous/ the respiratory elevator?
    • Mucous traps bacteria
    • Respiratory Elevator: cillia in bronchioles continuously move dust and debris up and away from the lungs.
  8. what are the 2 types of Cellular and Chemical defenses?
    • 1. Phagocytes
    • 2. Opsonization
  9. What is a Phagocyte?
    Phagocytes engulf particles in a phagosome which is then combined with lysosome to form a phagolysosome. Free radicals are also produced in the phagolysosome
  10. Phagolysosome
    the name of a combined lysosome and phagosome (phagocyte)
  11. What are the 2 major types of Phagocytic cells?
    • 1. Macrophages- monocytes
    • 1. Microphages- neutrophils and eosiniphils
  12. Macrophages
    • formed from monocytes that leave the bloodstream and enter tissue
    •      a. specific receptors for complement proteins and antibodies; can be "activated" ; nonspecific
    •      b. express antigen fragments of surface for interaction with T-cells
  13. Fixed macrophages are found only in specific areas of the body. What are these two areas?
    • Kupffer cells- liver
    • Alveolar macrophages- alveoli
  14. Neutrophils
    • Diapedesis- squeezing between endothelial cells of the blood vessels
    • Chemotaxis- attraction of neutrophils
    • Neutrophils can produce defensin, bleach, and hydrogen peroxide.
    •      a. self destruct after they engulf something
  15. Diapedesis
    squeezing between endothelial cells of the blood vessels
  16. Chemotaxis
    the attraction of neutrophils
  17. Eosinophils
    • weakly phagocytic
    • more important against parasites
  18. which type of denfense cell is more important agaisnt parasites?
  19. Mast cells
    usually associated with allergies, may have phagocytic properties
  20. Opsonization
    foreign particles coated with antibodies, complement proteins.
  21. Natural Killer Cells
    • 1. Lyse cancer cells and virus-infected cells
    • 2. large granular lymphocytes called null cells / third population cells (TPC)
    • 3. detect cell surface changes on ANY cell (nonspecific)
    • 4. destroy infected cell by release of cytolytic chemicals (perforins)
  22. What is the name of cytolytic chemicals released by Natural Killer cells?
  23. What is the name of tissue's response to injury?
  24. What is the purpose of inflammation?
    • 1. prevent spread of damaging agent
    • 2. dispose of cell debris and pathogens
    • 3. set stage for repair process
  25. Process of vasodilation involving Macrophages
    Macrophages lining boundary tissue contain surface receptors called Toll-like receptors. When stimulated, TLR cause release of cytokines with attract WBC
  26. Mediators released from cells to initiate vasodialition
    • Histamine, kinins, PGs, complement
    • Macrophages' Toll-like receptors release cytokines to attract WBC
  27. Edema
    Bacterial toxins and edema cause pain
  28. Defensins
    Broad spectrum antibiotics that come from neutrophils
  29. Leukocytosis
    Injured cells release chemicals which cause bone marrow to release neutrophils
  30. Margination (pavementing)
    • neutrophils line inner walls of capillaries
    • Diapedesis- squeeze between the endothelial cells and out of the blood vessel
    • Chemotaxis- monocytes follow the neutrophils and eventually convert to macrophages
  31. What is the name of Cell Adhesion Molecules located on neutrophils?
  32. What is the name of cell adhesion molecule produces by endothelial cells?
  33. What is pus?
    • dead and dying neutrophils, broken down tissue cells, and living and dead pathogens.
    • Abscess- sac of pus that can be walled off by collagen fibers
  34. What are the two categories of Antimicrobial Protein action?
    • 1. Interferon
    • 2. Complement proteins
  35. What is Interferon?
    what are its effects?
    • protein secreted by cells infected with viruses
    •      a. IFN are not virus specific
    • Causes neighboring cells to produce PKR which inhibits viral replication.
    • Interferons also activate macrophages and natural killer cells
  36. How do Complement proteins work?
    • group of plasma proteins which, when activated, enhance inflammation and cause lysis.
    • Two Pathways:
    •      a. classical
    •      b. alternative
    • Important component of humoral immunity
  37. What is the classical pathway of Complement proteins?
    • Antibodies bind to invader and change its shape exposing complement binding site of C region
    • C3 is cleaved into C3a and C3b
    • C3b causes the insertion of Membrance Attack Complex (MAC)
    • In addition, C3b coat microorganism providing sites that macrophages recognize and attack (opsinization)
  38. How is C-reactive protein involved in the classical pathway of Complement proteins?
    C-reactive protein is formed by liver in response to inflammatory molecules. Binds to C1 of the classical pathway and results in deposition of C3 on bacteria wall
  39. Alternative pathway of Complement proteins
    • Complement does not require antibodies
    • MAC forbed by other substances in yeasts, viruses, virus-infected cells, and protozoan parasites.
    • part of nonspecific immune responce
  40. Specific Body Defenses (Adaptive immune system)
    • specificity- eliminates particular antigens by producing specialized lymphocytes and antibodies
    • Diversity- recognizes millions of antigens
    • Self/ non-self recognition
    • memory
  41. Humoral Immunity
    • Involves antibodies secreted from lymphocytes and complement
    •      a. 5 classes of Ab
    • Against toxins, free bacteria, and viruses
  42. Cell-mediated immunity
    • Direct action of cells
    • bacteria and viruses inside host's cells; fungi, protozoans and worms
    • tissue transplants
  43. Definition of Antigen
    Substances that can mobilize the immune system and provoke and immune response.
  44. 2 classes of antigens
    • 1. complete- stimulate prolifereation of specific lymphocytes
    • reactivity: ability to react with activated lymphocytes
    • 2 incomplete- by themselves cannot cause immune response, but when linked to bodies own proteins can then be recognized.
  45. Antigen Determinants
    Only the antigen determinant part of an antigen is immunogenic
  46. Self Antigens: MHC proteins
    • on the surface of all cells
    • practically infinite number if gene combinations for MHC, like a finger print
  47. 2 main classes of Major Histomatibility Complexes
    • Class I- nucleated cells
    •      a. display self antigens (endogenous antigens)
    • Class II- macrophages and B lymphocytes
    •      a. can display foreign antigens ( exogenous)
  48. Cells of Adaptive Immune System
    Includes Lymphocytes and Antigen-Presenting Cells
  49. 2 Classes of lymphocytes
    • 1. B-cells- bone marrow; humoral immunity
    • 2. T-Cells- bone marrow to Thymus gland; cell-mediated immunity
  50. how are T-cells selected?
    • Positive selection: fetal T-cells that can recognize self MHC are retained. If unable to recognize self, then they undergo apoptosis
    • Negative selection: T-cells that bind too strongly to self MHC are eliminated
  51. How are B-cells selected?
    • 1. Anergy: Self reactive B cells are inactivated by process called anergy
    • 2. Clonal deletion: Other B-Cells killed outright or physically eliminated.
  52. Antigen-Presenting Cells
    • Engulf antigens and present fragments of antigens on their surface in MHC class II.
    • Includes Macrophages and activated B lymphocytes.
  53. Specific locations of  some APC
    • Dendritic cells- in connective tissue
    • Langerhan's cells- skin epidermis
  54. How are T cells activated (adaptive immune system)
    • Dendritic cells and macrophages secrete soluble proteins that activate T cells
    • Activated T cells then mobilize and cause maturation of dendritic cells and activate macrophages.
  55. how do Lymphocytes leave the blood system?
    Lymphocytes leave system because of cell adhesion molecules CAM found of endothelial cells.
  56. Humoral Immunity Response (2 steps)
    • 1. Antigen binds to receptor on B-cell
    • 2. Macrophages and helper t-cells
  57. Clonal Selection and Differentiation of B-cells
    A B-cell is activated by binding an antigen to its surface, then internalizing it. The B-cell grows and creates clones. Most progeny become plasma cells; some become memory cells
  58. Immunlogical Memory
    • 1. Primary immune response- 3-6 day lag
    • 2. Secondary immune response- quicker and more aggressive
  59. What is the structure of an antibody?
    • Image Upload4 polypeptide chains linked by disulfide bridge: 2 light chains and 2 heavy chains.
    •      a. constant region
    •      b. variable region- antigen binding site
  60. what portion of blood are antibodies located in?
    Constitute gamma globulin portion of blood
  61. How do immunoglobulins interact with antigens?
    • Soluble proteins: interact with epitope on antigens
    • epitope: a small, restricted site on an antigen molecule that induces immunity through specific binding with either an antibody or a T-cell receptor.
  62. how many classes of antibodies are there?
  63. Why/ how are antibodies so diverse?
    Enbryonic DNA has multiple variable, four joiner regions and one constant region. These can be manipulated to form nearly infinite combinations
  64. Antibody Targets and Function
    • 1. Complement fixation and activation
    • 2. Neutralization: Binding of antigen causes neutralization
    • 3. Agglutination: think of lots of people tackling a gunman
    • 4. Precipitation
  65. What properties of monoclonal antibodies allow them to be used for clinical testing?
    very specific; can be produced by fusing tumor cells and B lymphocytes to form hybridomas. Hybridomas proliferate indefinitely in culture and produce a single type of antibody.
  66. Cell- Mediated immunity targets pathogens where?
    cell mediated immunity battles pathogens already inside cells
  67. What is the key component of cell mediated immunity?
    • T-cells
    • 2 major populations:
    •      a. CD4- helper T cells
    •      b. CD8-cytotoxic T-cells
  68. CD4- Helper T cells
    • activate B cells to secrete Antibodies; also activate other T-cells
    • Only recognizes antigen in type II MHC, Antigen Presenting Cells (macrophages and B-cells)
    • For Helper T-cells to activate other lymphocytes, cytokines must be present.
  69. CD8- Cytotoxic T-cells
    • destroy other cells; only T cells that actually kill other cells
    • recognize antigens associated with class I MHC markers
    • Cytotoxic T-cells attack as long as appropriate antigen and co-stimulatory signal present.
  70. T-cells
    • not activated by free antigens; activated only by antigenic epitopes displayed on surfaces of bodies own cells.
    • must be able to recognize foreign and self through MHC
  71. Class I MHC
    • displayed on virtually all cells of body except for red blood cells.
    • recognized by CD8- Cytotoxic T-cells
  72. Class II MHC
    • found on some mature B cells, some T cells and Antigen Presenting Cells
    • enable cells of the immune system to recognize each other.
    • Class II MHC only recognizes exogenous antigens (foreign antigens phagocytized and borken down in phagolysosome)
    • are recognized by CD4 helper T-cells
  73. What is the role of cytokines in Helper T cell actions?
    • Cytokines are molecules which regulate neighboring cells
    • For helper T-cells to activate other lymphocytes, cytokines must be present
  74. How is Interleukin-1 produced and what is its effect?
    • Binding of helper T-cells causes macrophages to release interleukin-1
    • interleukin-1 signals helper t-cells to release interleukin-2
    • Stimulates helper T-cells to grow and divide
  75. What kinds of cytokines can activated T cells produce?
    • interleukin-1
    • Tumor necrosis factor-kills cells
    • interferon- enhances ability of macrophages.
    • interleukin-2 stimulates B-cells to produce Ab
    • Cytokines can also stimulate T-lymphocytes to differentiate into cytotoxic T-cells
  76. T-cell independent antigens
    • Antigens that stimulate B cells without help from T-helper cells
    • produce weak responses
  77. T-cell dependent antigens
    • require T-helper cells
    • more potent antigens
  78. What do Cytotoxic T-cells target?
    only T-cells that actually kill other cells: attach virus-infected cells, and cells infected by intracellular bacteria, parasites, cancer cells, and foreign cells
  79. What is the "lethal hit sequence" of cytotoxic T-cells?
    • Tc release perforin and granzymes which form lesion in infected cell's membrane
    • with calcium present, perforin polymerize and create transmembrane hole
    • granzymes enter target cell through holes and then degrade cellular contents causing apoptosis
    • some Tc release lymphotoxin, TNF, or gamma interferon to cause cell death
  80. What is perforin?
    puts hole in cell membrane. part of Tc lethal hit sequence
  81. what are granzymes?
    interfere with the membrane of a cell and degrade cellular contents as part of Tc lethal hit sequence
  82. Other types of T cells (other than Helper and Cytotoxic)
    Suppressor T-cells: suppress activity of B cells and other T cells; helps keep immune system in check.
  83. Autoimmune diseases
    • 1. Lupus erythematosis and rheumatoid arthritis
    • 2. Insulin-dependent diabetes: attacking own beta cells
    • 3. Rheumatic fever
    • 4. Grave's disease- attack Thyroid
    • 5. Multiple Schlerosis- attack myelin sheath
  84. is AIDS an autoimmune disease, and allergy, or an immunodeficiency?
  85. Blood groups
    • Explanation: type A blood has A antigens, so if you put A blood in a type B person, formation of "anti A antigens" antibodies will occur.
    • Rh factor: Rh-negative mother can develop antibodies against fetus, treat mother with anti-Rh antibodies after birth
  86. What is responsible for tissue rejection in tissue grafts?
    • MHC is responsible for tissue rejection
    • causes cytotoxic T-cells to mount cell-mediated immune response.
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ALS 2304 Animal Anatomy Final Exam: Immunity
2014-12-03 13:31:29
VT Animal Anatomy Final Exam

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