Adaptive Immunity

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Adaptive Immunity
2012-08-27 15:57:59
Adaptive Immunity

Adaptive Immunity terms
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  1. What is the chromosome number of:
    - heavy chain
    - kappa light chain
    - lambda light chain
    - alpha chain
    - beta chain
    - HLA complex
    • heavy chain: 14
    • kappa light chain: 2
    • lambda light chain: 22
    • alpha chain: 14
    • beta chain: 7
    • HLA complex: 6
  2. Epitope
    the part of an antigen to which an antibody binds
  3. Recombination Signal Sequence
    • two types
    • nonamer, heptamer, 12 bp spacer
    • nonamer, heptamer, 23 bp spacer
  4. 12-23 rule
    In order to join V, D, or J gene segments, you need a 12 spacer and a 23 spacer
  5. V(D)J Recombinase
    • set of enzymes used to recombine V, D, and J gene segments.
    • consists of RAG1 and RAG2
  6. Terminal deoxynucleotidyl transferase
    adds nucleotides to opened hairpin DNA strands
  7. Igalpha and Igbeta
    coreceptors for immunoglobulins that function to interact with intracellular signaling proteins.
  8. somatic hypermutation
    random introduction of single nucleotide substitutions throughout the variable regions of heavy and light chains
  9. Activated-induced cytidine deaminase (AID)
    converts cytosine --> uracil, so CG pairs become AT pairs
  10. affinity maturation
    B cells that have mutant high-affinity immunoglobulin receptors compete more effectively for binding of antigen, thus they are preferentially selected to mature into antibody secreting plasma cells.
  11. Isotype switching
    brings in a new constant region to interact with the variable region sequence
  12. TAP
    The TAP transporter dimer is critical for transfer of peptides from the cytosol into the endoplasmic reticulum
  13. ERAP
    in the ER, if the MHC class I molecule is loaded with a peptide that is too long, ERAP removes N-terminal amino acids until the peptide is abou 8-10 residues
  14. Invariant chain
    prevents peptides from binding to a MHC class II molecule until it reaches endocytic vesicles
  15. CLIP
    when the invariant chain is cleaved, CLIP is left behind and is bound to the MHC class II molecule
  16. HLA-DM
    catalyzes the release of CLIP from the MHC class II molecule, thus allowing for peptides to bind
  17. polymorphism
    each individual is likely to express 2 different allelic HLA molecules from each locus
  18. polygeny
    refers to the duplication of HLA genes
  19. c-kit ligand
    • c-kit (on B cell) binds to stem cell factor (of stromal cells in bone marrow).
    • kit causes the B cell to proliferate
  20. surrogate light chain
    • consists of VpreB and lambda 5
    • the binding of the surrogate light chain with the heavy chain on Pre-B cell receptors is the first checkpoint
  21. IL-4
    required for the differentiation of the pre-B cells to immature B cells
  22. Follicular dendritic cell
    • secrete chemokines in the lymph node that attract immature B cells to enter via the high endothelial venule.
    • they also secrete another chemokine that attracts the B cell to the primary follicle
    • interactions with the follicular dendritic cell and cytokines drives maturation of the B cell. This is indicated with the expression of more IgD compared to IgM.
  23. Thymic Involution
    T cell production decreases with age
  24. positive selection
    • T cell receptors that bind to MHC with a moderate affinity move to the next stage (which is negative selection)
    • double positive thymocyte becomes a CD4 T cell or CD8 T cell
  25. Negative selection
    T cells that bind too tightly to MHC on dendritic cells, macrophages, etc are signaled to die
  26. self MHC restriction
    A T lymphocyte can only respond to a peptide antigen in the conext of the same MHC type encountered during the selection process in the thymus.
  27. LFA-1
    LFA-1 is a cell surface adhesion molecule on the T cell that binds with ICAM-1 of the dendritic cell
  28. ICAM-1
    LFA-1 is a cell surface adhesion molecule on the T cell that binds with ICAM-1 of the dendritic cell
  29. alloreactivity
    • T cell response to foreign MHC
    • two modes of cross-reactive T cell recognition that may explain alloreactivity - peptide dominant and MHC dominant binding
  30. CD3
    • CD3 is a co-receptor that is always expressed with the T cell receptor.
    • CD3 is critical for transmitting the signal from the APC to the T cell
  31. immunoreceptor tyrosine-based activation motifs (ITAMs)
    • ITAMs are the cytoplasmic tails fo the CD3 proteins.
    • phosphorylation of the ITAM by Lck allows for ZAP-70 to bind to it
    • ZAP-70 initiates the intracellular signaling pathway¬† leading to T cell activation
  32. ZAP-70
    ZAP-70 binds to phosphorylated ITAMs, which then initiates the intracellular signaling pathway leading to T cell activation
  33. lck
    • phosphorylate ITAMs
    • get phosphorylated (activated) when the TCR/MHC/co-receptor complex binds together
  34. fyn
    same function as lck
  35. CD45
    protein tyrosine phosphatase that activates lck and fyn by removing the phosphate from the inhibitory site.
  36. what are the two independent signals required for activation of naive T cells
    • TCR/co receptor binding of MHC/peptide complex
    • CD28-B7 co-stimulation
  37. CD28
    • co-stimulatory molecule found on T cells
    • binds to B7
  38. B7
    • co-stimulatory molecule found on APC
    • binds to CD28
  39. Anergy
    T cell becomes permanently disabled when there is no co-stimulation
  40. CTLA-4
    • an inhbitory receptor expressed on T cells
    • CTLA-4 binds B7 more avidly than does CD28 and delivers inhibitory signals to activated T cells
  41. IL-2
    • function: promotes T cell proliferation
    • T cell activation causes the secretion of IL-2 and expression of IL-2 receptors
    • IL-2 binds to the IL-2 receptors to cause T cell growth in an autocrine fashion
  42. perforin
    released from granules of cytotoxic T cells and inserts into the target cell membrane to form pores
  43. granzymes
    serine proteases, which activate apoptosis once in the cytoplasm of the target cell
  44. granulysin
    has antimicrobial actions and can induce apoptosis
  45. IFN-gamma and CD40 ligand
    activate macrophages to destroy engulfed bacteria
  46. Fas ligand or LT
    kills chronically infected macrophages
  47. IL-3 + GM-CSF
    induces macrp[hage differentiation in the bone marrow
  48. TNF-alpha + LT
    activates endothelium to induce macrophage adhesion and exit from blood vessel at site of infection
  49. CXCL2
    causes macropphages to accumulate at site of infection
  50. Cytokines secreted by activated T1 helper cell
    • IFN-gamma and CD40 ligand
    • Fas ligand or LT
    • IL-2
    • IL-3 + GM-CSF
    • TNF-alpha + LT
    • CXCL2
  51. cytokines secreted by helper2 T cells
    • IL-4
    • IL-5
    • IL-10
    • IL-13
    • TGF-beta
  52. cytokines and cytotoxins secreted by cytotoxic T cells
    • IFN-gamma
    • LT
    • perforin
    • granzymes
    • granulysin
  53. Regulatory T cells
    limit the activities of effector and autoreactive CD4 and CD8 T cells