Bmsc210 final p3

  1. Case of PLL hapten and BSA
    • -Hapten PLL doesn't evoke immune response
    • -after immunization to BSA, PLL-BSA is able to precipitate
    • -after this PLL will precipitate serum on its own.
    • - Thus the antibody could bind PLL and yet PLL could not induce the formation of antibody.
    • -proved binding of antigen to antibody-like receptors of the precursor cell doesn't induce production of this antibody
  2. Direct Antigen Binding Model for Precursor Cell Activation
    -Antigen supposedly binded directly to precursor cell

    • - did not explain how haptens could bind to antibodies(precipitation) but not induce antibody production(PLL-BSA)
    • -proof that B-cells and T-cells are need to induce response(irradiated mice)
  3. immunogenic substance
    A substance that can induce antibody production
  4. non-immunogenic substance
    • -small molecules do not elicit immune responses (hapten)
    • -can still be rather larger than the size of an amino acid
  5. Hapten
    • -small molecules that cannot elicit immune responses
    • -some macromolecules haptens exist that can bind antigens but do not produce immune response which is confusing
  6. hapten-carrier conjugate
    • -immunogenic macromolecule that are conjugated to haptens
    • -If a hapten bound to one foreign substance elicits an immune response it will do so if found on another even if the other is non-immunogenic
  7. thymectomy
    Removal of thymus
  8. immunoincompetent
    unable to form immune response
  9. in order for irradiated mice to produce antibodies they need to be injected with:
    bone marrow cells AND thymus cells(thymocytes)
  10. Antigen Bridge model of B cell/ T helper
    (relation to PLL)
    • -T cell and B cell both bind to antigen from opposite sides
    • -absence of response to PLL would be due to lack of PLL specific T helper to complete the bridge
    • -PLL-BSA is recognized because there are many BSA specific T helpers so b binds to PLL side and T helper binds to BSA side
    • Downfall:
    • helper CD4+ T cells do not bind to antigens they bind to class II MHC bound proteins
  11. MHC-restricted B cell/T helper cell interaction model
    (relation to PLL)
    • -B cells recognize specific antigens and engulf them through endocytosis, digest them and display antigen specific proteins on their Class II MCH structures.
    • -T helper cells then bind onto said proteins and give signals to B cell for induction

    -if PLL B cell engulfs PLL-BSA it can display BSA on MHC II and be activated by BSA T CELL creating PLL anti bodies
  12. process of SELF TOLERANCE(3 points)
    -receptor-bearing precursor cell arises from a stem cell with out receptors

    -if the cell, when it first expresses a receptor, interacts with antigen, it will die (usually a self antigen because they are always present)

    -Cells with receptors that do not interact with a self antigen will not die, and will mature into a different state that is inducible
  13. antigen-specific inactivation
    • -when an antigen interacts with a B cell before maturity it results in the death of the B cell.
    • -ensuring that anti-self B cells are eliminated
  14. epitope
    • The area on an antigen molecule complementary to an antibody molecule
    • ex: MSA and RSA(mouse/rat serum albumin)
  15. crossreactivity
    the ability of an antibody to precipitate antigens with epitopes in common
  16. induction of autoimmunity
    • -when a foreign antigen is cross reactive with a self-antigen autoantibodies can be created if the self-B cells have not all been weeded out
    • -B cells can mistake cross reactive antigens for each other

    -this is viable for both theories of B-T Cell collaboration
  17. 2 Examples of cross reactive antigens causing autoantibodies
    • -group A streptococci cross react with heart tissue
    • -development of rheumatic heart disease is believed to be due to an autoimmune response to heart tissue following such an infection

    -Rabbit thyroglobulin cross-reacts with turkey thyroglobulin
  18. CD4 T cells
    (effects on other cells)
    • -Th Helper cells
    • -Bears Thy1 antigen which activates B cells to produce progeny
    • (B cells die if they interact with antigens and no CD4 T cells bond)
    • -Bond to MHCII (macrophages/B cells)
  19. the induction of different classes of immunity is often ___
  20. 4 examples where cell-mediated immunity is better than just humoral or both.
    • leprosy
    • Mycobacterium leprae

    • tuberculosis
    • Mycobacterium tuberculosis


    visceral leishmaniasis
  21. What are humoral responses well suited for?
    toxin neutralization
  22. humoral immune deviation
    • -caused by Th2 CD4 cells that inhibit cell mediated immunity(DTH) when antibodies are produced
    • -caused mainly by secretion of IL4 which increases IgG and IgE response
  23. cell-mediated immune deviation
    • -caused by abnormal Th1 CD4+ cells that inhibit antibody production when cell-mediated immunity is induced
    • -mainly caused by IFNy
  24. delayed-type hypersensitivity (DTH)
    A cell mediated immune response
  25. a T cell specific for an antigen will be present once in about ___ spleen cells
  26. IL2
    • -a particular growth hormone for T cells
    • -one T cell, stimulated with antigen in the presence of IL2, will give rise to upwards of a million identical cells
  27. cytokines
    (secreted by__, When, to ___)
    • -Molecules secreted by CD4 T cells after bonding to B cells
    • -molecules are normally delivered to target cells when the producing cell binds to the target cell with its receptor
    • -either positively or negatively regulate the growth and differentiation of other cells, including other T cells
    • -Different T cell secrete different Cytokines
  28. Th1 CD4+ cells produce ___ and ___
    IL2(growth Factor for T cells)

    IFN-y(Can prevent viral multiplication and activate Macrophages)

    -These functions suggest a central role for Th1 cells in cell-mediated immunity
  29. Pathogens that infect macrophages(3)
    Mycobacterium leprae 

    Mycobacterium tuberculosis 

  30. Virus-specific CD8+ T cells
    • -generated upon viral infection,
    • -often deliver IFNy to and are cytotoxic for virus-infected cells.
    • -a central component of the cell-mediated response.
  31. angry macrophages
    macrophages activated by IFN-y
  32. Th2 CD4 cells secrete ___ and ___
    IL4: increases IgG and IgE responses


    -These functions suggest a central role for Th2 cells in Humoral immunity
  33. Th1 cells inhibit Th2 cells with ___
    Th2 cells inhibit Th1 cells with ___
    • IFNy-activation of macrophages/AVP
    • IL-4-increased response of anti bodies
  34. it is possible to make tumor cells express the antigen ___ required to stimulate T cells.
    • B7
    • -this increases the magnitude of the CD8+ T cell cytotoxic response in tumor bearing hosts resulting in all tumor cells being killed more readily
Card Set
Bmsc210 final p3
Bmsc210 final p3