OralImmunology - 0516 - L1,2

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  1. The Immune System protects by _________.
    Self vs. non-self discrimination
  2. Antigen = compounds known to cause __________.
    antibody response to be generated
  3. Two broad means by which the Immune system deals
    • with pathogens
    • Acquired (Specific or Adaptive) Immunity
    • Innate (Nonspecific or Natural) Immunity
  4. Innate immunity
    • immediate: 0-4 hours
    • Infection ->
    • Recogntion by preformed, nonspecific and broadly specific effectors ->
    • Removal of infectious agent
  5. Early induced innate response
    • early: 4-96 hours
    • Infection ->
    • Recruitment of effector cells ->
    • Recognition of PAMPS. Activation of effector cells and inflammation ->
    • Removal of infectious agent
  6. Adaptive immune response
    • late: >96 hours
    • Infection ->
    • Transport of antigen to lymphoid organs ->
    • Recognition by naive B and T cells ->
    • Clonal expansion and differentiation to effector cells ->
    • Removal of infectious agent
  7. Comparison of Innate and Adaptive Immunity
    • Innate Immunity: No time lag; Not antigen specific; No memory
    • Adaptive Immunity: A lag period; Antigen specific; Development of memory
  8. Schematic structure of antigen receptors
    • Variable region - antigen binding; fine tuning
    • Constant region - effector
    • Similar between Ab and T-cell surface receptor
  9. Structure of Ig
    • Two heavy chains - disulfide bonds
    • Two light chains - linked to heavy chains via disulfide bonds
    • Both chains are made of variable and constant regions.
  10. ________ are the molecules recognized by the immune response; ______ are regions to which ______ bind.
    • Antigens
    • Epitopes
    • antigen receptors (of Abs), aka paratope
  11. Papain cleaves Ig into __________; pepsin cleaves Ig into __________.
    • 2 Fab (fragment antigen binding) and Fc (fragment crystalizable)
    • F(ab')2 interconnected and 2 pFc' (multiple pieces due to multi-site cleavage)
  12. The course of a typical antibody response
    • lag phase + primary response (novel antigen)
    • Secondary response
  13. In a primary response the first class of Ab detected is usually ___. _______ is said to occur when the constant heavy chain of the Ab changes to other isotypes.
    • IgM
    • Isotype switching
  14. The immunoglobulin isotypes are encoded by ______.
    a cluster of Ig heavy-chain C-region genes
  15. In secreted form, IgA is in the form of a ___ that is hooked by the ____; IgM ____ (hexamer of IgM also exists but is rare).
    • dimer
    • J chain
    • pentamer by J chain
  16. Valency and avidity of Ab-Ag interactions
    • how many valent bonds used per Ig to bond Ag - monovalent, bivalen, polyvalent.
    • the level of interaction: more bond, higher avidity. low, high, very high
  17. Highest molecular size of Ig of different classes
    IgM, most labial, degrades easily
  18. Serum level of Ig
    • IgG is the highest, followed by IgA
    • IgE is the lowest
  19. Half life of Ig
    IgD and IgE are the shortest.
  20. Ig light chain isotypic variants
    • kappa (Κ)
    • lambda (Λ)
    • Encoded by different genes at different loci
    • Either type can combine with any heavy chain
  21. T cell receptors
    • alpha and beta chains
    • both have variable and constant regions
  22. Cytokines:
    • Released by leukocytes & other cells
    • Chemical messengers
    • Balance between cell mediated & adaptive immunity
    • Pleiotrophy (more than one action; contrary to redundancy)
    • Autocrine (act on producing cells)
    • Paracrine (act on cells other than producers)
    • Antagonism (one cytokine may act against another)
    • Lymphokines are produced by lymphocytes (no longer valid definition); Monokines are produced by monocytes and macrophages (no longer valid definition); Old names have stuck!
  23. Chemokines:
    • Chemoattractant cytokines produced in earliest
    • phase of infection and other immune responses; attract other cells.
    • CXC (two invariant cysteines separated by a single AA) chemokines
    • CC (two invariant cysteines) chemokines
  24. Cluster of differentiation Ags
    • CD
    • Cluster of antigens with which Ab react, and that characterize cell surface molecules
  25. Two major types of Cells involved in Host Defense:
    B and T cells
  26. B cells mature into _______ – making
    • _________ (“______” arm of host defense)
    • antibody producing plasma cells
    • immunoglobulins
    • humoral
  27. heavy chain
    • - Ig classes - IgM, IgD, IgG, IgA, & IgE. Determined by H chain
    • Ig isotypes are determined by sequences in the H (µ, δ, γ, α and ε, respectively), and light (L) chains (λ and κ)
  28. T cells constitute the ____ arm of host defense.
    cellular
  29. Components of the immune system:
    • 1. Many are actually cellular in nature and not associated with any specific organ but rather are embedded or circulating in various tissues located throughout the body.
    • 2. Many are proteins that circulate to direct or attract cells of the immune system to their target sites.
  30. Distribution of lymphoid tissues in the body
    • Central (primary) lymphoid organs
    • Peripheral (Secondary) lymphoid organs
  31. Central (primary) lymphoid organs
    • Bone marrow
    • Thymus
  32. Peripheral (Secondary) lymphoid organs
    • Sites of activation
    • lymph nodes
    • Spleen
    • Mucosa associated:
    • - gut-associated tonsils
    • - Peyer’s patches - small nodes lining the small intestines
    • - appendix
  33. The spleen
    • Red pulp: Site of RBC destruction
    • White pulp: Lymphoid cells; from circulation.
    • - contains central arteriole surrounded by lymphoid sheath with lymphoid cells, B-cell area, etc.
    • Structure is similar to lymph nodes.
  34. The spleen has no connection with the lymphatic
    • system; all cells enter the spleen from _____ and
    • exit directly back into it.
    • the blood
  35. Lymph node
    • Paracortical area - T cells
    • Primary lymphoid follicle - naive/virgin B cells
    • Secondary lymphoid follicle - in the germinal center, B cells exposed to antigens coming from the lymphatics and developed, producing antibodies, fine tuned by variable region changes. If have mistakes, will self-destroy. Susceptible to oncogene mutations which lead to lymphoma.
    • Senescent germinal center - self-dissolve germinal center at the late stage.
  36. Peyer's patch - small bumps lining small intestine; contains _____ and _____, covered by small intestine _______ containing specialized _____ which have characteristic ________, through which they capture antigens passing by and bring them inside.
    • germinal centers
    • T cell area
    • epithelial layer
    • M cells
    • membrane ruffles
  37. Other mucosa areas
    • Gut mucosa
    • NALT (nasal-associated lymphoid tissue)
    • BALT (bronchus-associated lymphoid tissue)
    • All arranged in similar way as small intestine mucosa.
  38. Thymus
    • Cortex - training area
    • Medulla
  39. Lymphocyte recirculation
    Lymphatics carry lymph which takes Ags from sites of infection to draining lymphoid organs. Activated & nonactivated lymphocytes return to bloodstream, and reach sites of infection.
  40. Afferent lymphatics go to lymph nodes.
    not the Peyer's patch
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OralImmunology - 0516 - L1,2
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Oral Immunology - 0516 - L1,2
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