immuno chapter 5.txt

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immuno chapter 5.txt
2011-03-02 21:01:13
immuno chapter

immuno chapter 5
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  1. TCR is made up of...
    Antigen-binding site, constant and variable region, CDR regions
  2. How many polypeptide chains make up a TCR?
  3. What characteristics does a TCR have?
    all the TCR on the same cell are the same. each cell expresses a different TCR
  4. Tc, TCL, CTL
    cytotoxic t cell
  5. MHC=
  6. What are the differences between TCR and BCR
    TCR only has one binding site, they do not bind to soluble antigens, they have no rearrangement after antigen engagement, Matures in thymus, only used for recognition, no secreted receptor
  7. How many CDR loops does a TCR have?
    6 (3 on each chain)
  8. What does TCR bind?
    MHC-peptide complex
  9. Calpha has how many options for rearrangment?
  10. Cbeta has how many options for rearrangment?
  11. what sections does the alpha chain have?
  12. What sections does the beta chain have?
  13. Where does rearrangment occur?
  14. What is a RAG proteins?
    recombination enzyme specific to T and B cells
  15. What two parts make up a transposon?
    Transposase (RAG) and Inverted repeates (RSS)
  16. What are the functions of CD3 and zeta?
    help transport the TCR to the cell surface and transmission of signal extracellular to intracellular
  17. SCID
    Severe combined immunodeficiency disease. people with SCID are susceptible to infections. lymphocyte profile (T- B- NK+), bone marrow transplant cna cure
  18. Omenn syndrome
    RAG proteins have reduced activity. patient is T+ but low, B- NK+
  19. CD3delta and CD3epsilon deficiency diseases
    mutations in some CD3 genes. patient is either T+/TCR- or T- and B+ NK+
  20. alpha:beta T cells make up how much of the population?
  21. gamma:delta T cells make up how much of the population and where do they occur?
    5%, predominate in epithelial tissue; recognize more than MHC-peptide complex
  22. Which TCR genes are together on a locus and what does this mean?
    delta and alpha chain genes share a locus meaning that if the alpha chain is rearranged then the delta chain cannot be made. This is the decision point for a t cell to become an alpha:beta or gamma:delta
  23. Antigen Processing-
    antigen is broken up and brought to surface
  24. Antigen presentation
    MHC=peptide complex is displayed on the cell surface
  25. Antigen Presenting Cell
    cell with a surface MHC-peptide
  26. Professional APC
    super presenters that are leukocytes
  27. What do t cells do after recognizing an antigen?
    they induce changes in other cells
  28. What do CD4 helper t cells do?
    help other cells
  29. What does Th1 do?
    changes a macrophage
  30. What does TH2 do?
    changes a b cell or dendritic cell
  31. What does CD8 CTL do?
    kills other cells
  32. What are CD4 and CD8?
    co receptors that help bind to MHC I and MHC II
  33. CD8 T CELL + virus infected cell =
    dead virus infected cell
  34. CD4 T cell + macrophage =
    activated macrophage
  35. CD4 T cell + B cell =
    Plasma cell
  36. How does MHC I display an antigen?
    the pathogen replicates in the cell and proteins are degraded in the cytoplasm of the cell. peptides are then transported into the ER and bind to MHC I and then transported to the cell surface. MHC I expressing cells present to CD8 T cells. CD8 T cells (CTLS) kills the host cell using perforin and granzymes... NO ANTIBODIES
  37. How does MHC II display an antigen?
    Pathogen is recognized and internalized by a professional APC. Phagolysosomes degrade the protein into peptides. The peptide-MHC II complex is transported to the cell surface. Professional APC contacts CD4 T cells. CD$ Th cells secrete cytokines to signal B cell maturation...Antibodies needed (recognize pathogen on APC)
  38. Which MHC binds to larger peptides?
    MHC II
  39. What is peptide binding groove?
    the binding spot on MHC binds to many different peptides that have similar features
  40. What on MHC I does CD8 bind?
    alpha 3
  41. What on MHC II does CD4 bind?
    beta 2
  42. What cells express MHC I?
    most human cells
  43. What cells express MHC II?
    leukocytes and thymic stromal epithelial cells
  44. IFN-gamma
    increases expression of MHC I and II
  45. Alleles
    DIfferent forms of one gene
  46. Allotypes
    different forms of one protein (isoforms)
  47. Polymorphic
    Alternative forms of one gene (many alleles)
  48. Oligomorphic
    A few forms of one gene (few alleles)
  49. Monomorphic
    no polymorphism
  50. Homozygous
    same allele on both inherited chromosomes
  51. Heterozygous
    different allele on both inherited chromosomes
  52. HLA- A, B, C
    present peptide antigens to CD8 t cells and interact with NK cells
  53. HLA- E, G
    interact with NK cells
  54. HLA- DP, DQ, DR
    present peptides to CD4 T cells
  55. IFN- alpha, beta, gamma
    increase expression of HLA class I heavy chain, B2 microglobulin, TAP, and proteasome subunits
  56. IFN- gamma
    increases expression of HLA class II
  57. Anchor residues
    residues in the peptide that anchor it to the MHC
  58. MHC restriction
    TCR recognizes the complex of both the peptide and MHC by interacting with exposed amino acid residues
  59. How many peptide chains of MHC class II contribute to plymorphism?
  60. How many peptide chains of MHC class I contribute to plymorphism?
  61. Peptide binding motif
    combination of anchor residues
  62. Balancing selection
    favors multiple alleles
  63. Directional selesction
    favors a single allele
  64. Haplotype
    the combination of alleles in a region of the chromosome
  65. why do heterozygous individuals have an advantage over homozygous individuals?
    they can recognize more peptides