Immuno - Lecture 1 - 2

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Immuno - Lecture 1 - 2
2014-10-05 17:36:58
Immuno Lecture
Immuno - Lecture 1
Immuno - Lecture 1
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  1. What is the main function of Regulatory T cells? INNATE IMMUNITY includes what?
    • Physical Barriers
    • Cellular Barriers
    • Chemical Barriers
  2. What are the Features of Innate Immunity?
    • First Line of Defense
    • Present on Birth
    • Non-specific
    • Resistance not improved by repeated infections
    • Physiological Barriers
    • Phagocytosis, Inflammation, Fever
  3. What are the characteristics of the Adaptive/Acquired Immunity?
    • Resistance improves after repeated infections
    • Cells involved include B lymphocytes, T lymphocytes and Macrophages
    • Primary and secondary lymphoid organs are involved in the process
  4. What is an IMMUNOGEN?
    Any agent inducing an immune response
  5. What are the characteristics of an immunogen?
    • Foreignness
    • High Molecular Weight
    • Chemical Complexity
  6. What is an Antigen?
    Any agent capable of binding specifically to components of immune response
  7. What are the antigens composed of?
    • Carbohydrates
    • Lipids
    • Nucleic Acids
    • Proteins
  8. What are Antibodies?
    Soluble globulin proteins
  9. What are the characteristics of antibodies?
    • Specificity
    • Distinct biological activity
    • Four chain structure: two identical light and two identical heavy chains
    • Three fragments of equal sizes
    • Fab fragment
    • Fc fragment
  10. What are the Functions of IgG?
    • Agglutination , precipitation and opsonisation
    • Conferral of immunity to fetus
    • ADCC
    • Activation of complement
    • Neutralization of toxins and viruses
    • Immobilization of bacteria
  11. What are the Properties of IgM?
    • Pentamer molecule
    • Synthesized after immunization
    • Elevated levels levels indicate recent infection
    • Synthesized by placenta and elevated levels in fetus indicative of congenital infection
    • Best agglutinating and complement-activating antibody
  12. What are the properties/functions of IgA?
    • Major immunoglobulin in secretions
    • Monomeric as well as Diameric
    • Role in Mucosal infections
    • Bactericidal Activity
    • Antiviral Activity
  13. What are the properties/functions of IgD?
    • Causes the differentiation of B cells to a more mature form
    • Present on the surface of B lymphocytes
    • Present in monomeric form
  14. What are the properties/functions of IgE?
    • Reaginic antibody
    • Protects against parasites
    • Important role in hypersensitivity
  15. How do Primary and Secondary Antibody Responses differ?
    • Time course; secondary response has a shorter lag phase and an extended plateau and decline
    • Antibody titer: greater in secondary response
  16. What are the LYMPHOID CELLS?
    • T cells: develop in the thymus
    • B cells: differentiate in fetal liver and adult bone marrow
    • NK cells: does not possess T cell or B cell receptors
  17. What are the characteristics of T Cells?
    • The definitive T cell marker is the cell antigen receptor (TCR)
    • TCR-1 (Composed of ϒ and Ϭ chains, 5%)
    • TCR-2 (Composed of α and β chains, 95%)
    • Both receptors are associated with a complex of polypeptides making up the CD3 complex.
  18. The TCR-2 cells are divided into two major subsets, what are they?
    • CD4+ (Helper T cells)
    • CD8+ (Cytotoxic T cells)
  19. CD4+ (Helper T cells) TCR-2 cells are divided into what subgroups?
    • CDw29+ (positively influence the immune response of T cells and B cells-the helper function)
    • CD45R+ (Induce cytotoxic function in CD8+ cells)
  20. Their principal functions include a negative feedback after the generation of an immune response and to protect from autoimmunity.
  21. CD4+ T cells mediate ________________independent of CD8+ T cells.
    suppressor function
  22. ____________ maintain self tolerance and suppress responses to foreign antigens.
    Regulatory T-cells
  23. ______________T cells are mature T cells with a distinct regulatory function.
  24. What are the main Regulatory T cells?
    • CD4+ CD25+ T cells,
    • peripheral Treg cells,
    • IL-10 secreting Tr1 cells
    • TGFβ secreting TH3 cells,
    • CD8+CD28- T cells, CD8+CD122+ T cells, Qa-1-restricted CD8+ T cells,
    • γ/δ T cells
  25. What are the features of Memory T cells?
    • Memory T cells persist even after the invading pathogen has been eliminated.
    • There are two types of memory T cells, central memory T cells and effector memory T cells.
    • They are either CD4+ or CD8+ and respond quickly after they see the antigen at a second time.
  26. What are the features of NKT cells?
    • They perform cytotoxicity and mostly are not MHC-restricted.
    • They recognize antigens which are glycolipids and require CD1d.
    • They release cytokines including IL-4, IFN-γ, GM-CSF. and others.
  27. What are the features of NKT cells?
    • NKT cells bridge innate and acquired immune responses.
    • Abnormal NKT cell function may be associated with cancer and autoimmune disease.
  28. What are the features of B lymphocytes?
    • These lymphocytes are unique due to their ability to secrete immunoglobulins (Defined by the presence of immunoglobulins)
    • B cells are produced in the bone marrow.
    • The development of B cells occur at various stages
    • Express both IgM and IgD molecules
    • Expression of IgG, IgA and IgE on the cell surface is not common in circulation
    • Majority of B cells carry MHC class II antigens
  29. What are the features of Natural Killer cells?
    • NK cells are the third largest class of lymphocytes.
    • They develop in bone marrow from common lymphoid progenitor.
    • NK cells share effector function and the ability to produce cytokines with T cells. They do not express either T cell or B cell receptors.
    • Large granular lymphocytes.
    • NK cells participate in innate immunity and are the first responders against infection and possibly tumors.
    • They carry CD56 antigen
    • The killing ability of NK cells is associated with the expression of MHC Class I molecules.
  30. What are the Antigen Presenting cells?
    • Macrophages
    • B cells
    • Dendritic cells
    • Langerhan cells
    • Interdigitating cells
  31. What are the features of Macrophages?
    • Macrophages participate in innate as well as acquired immune response.
    • They are phagocytes which continuously remove self proteins which are degraded and presented to T cells
    • The most important role of macrophages is antigen presentation.
    • They also play a role in inflammatory responses, anti-tumor activity, microbicidal activity, lymphocyte activation and tissue reorganization.
    • Most of their effects are mediated via cytokines.
    • They release oxygen dependent free radicals, collagenases, and angiogenesis factors.
  32. What are the features of Dendritic Cells?
    • Dendritic cells are antigen presenting cells.
    • They are distributed in small quantities in various tissues including skins, inner lining of the nose, lungs, stomach and intestine.
    • The blood contains immature dendritic cells.
    • After activation, dendritic cells migrate to the lymphoid tissue to initiate an acquired response after interacting with B and T cells.
    • There are two most common types of dendritic cells, myeloid dendritic cells and lymphoid dendritic cells.
  33. What are the features of Myeloid dendritic cells?
    • Secrete IL-12 and are very similar to monocytes
    • mDC can be divided into at least two subsets, mDC1 and mDC2.
    • mDC1 stimulates T cells, whereas mDC2 may have a role in fighting wound infection.
  34. What are the features of Lymphoid dendritic cells?
    • Similar to plasma cells and produce high levels of interferon-ϒ.
    • The dendritic cells are of hematopoietic origin.
    • The myeloid dendritic cells are of myeloid origin and lymphoid dendritic cells are of lymphoid origin.
  35. What are the features of Neutrophils/Polymorphonuclear leukocytes?
    • They are produced in the bone marrow.
    • Neutrophils are phagocytes.
    • They utilize a number of bactericidal substances, lytic enzymes, and both oxygen-dependent and oxygen-independent pathways to kill microbes.
  36. What are the features of Eosinophils/Polymorphonuclear leukocytes?
    • Eosinophils develop in bone marrow, where they also mature.
    • Eosinophils are also capable of phagocytosis.
    • They are involved in combating parasitic infection and play a role in allergic disease.
  37. What are the features of Basophils and Mast cells?
    • Basophils are of bone marrow origin.
    • They secrete a number of mediators including histamine, leukotrienes, and several cytokines.
    • Mast cells are similar to basophils, but they have different precursor cells in the bone marrow. The precursor cells for both basophils and mast cells express CD34.