Pathophys Test 2

  1. Review the role of the Major Histocompatibility Complex (MHC). (p.8)
    • Nucleated cells have histocompatibility molecules.
    • - On cell surface membrane
    • - Antigens or glycoproteins
    • - Identify cell as belonging to the host
    • - Also called HLA = human leukocyte antigens
    • Genes that code for MHC (HLA) located on chromosome 6 – area known as major Histocompatibility complex (MHC)
    • Important to cellular recognition events
    • Immunological activity influenced by antigens
    • - Activity of Cytotoxic T Cell
    • - Interaction between Macrophage and T Helper Cell
    • - Interaction between T Helper Cells and B Cells
  2. What are Class I antigens?
    Where would you find them?
    • Found on surface of virtually all nucleated somatic cells and platelets (not on RBCs)
    • - Coded by gene loci – HLA-A, HLA-B, -C
    • - Bind foreign peptides and present them as foreign antigens to Cytotoxic T cells (CD8 cells)
  3. What are Class II antigens?
    Where would you find them?
    • Found on immune cells – macrophages, B-cells, dendritic cells, Langerhan cells of skin, venular endothelial cells
    • - Bind to receptors on Helper T cells (CD4 cells)
    • - Coded by gene loci – HLA-DR, -DP, -DQ
  4. What is the role of Class I and Class II antigens in immune response?
    Present antigens to the immune system.
  5. What is an allele?
    • Different form or variation of the same gene.
    • Base sequence may be difference
  6. Cell surface membranes of T Cells also contain antigens called clusters of differentiation (CD).
    CD4 and CD8 antigens are associated with what cells? (p.11)
    • CD4 and CD8 antigens are adhesion glycoproteins, called clusters of differentiation that are expressed on T lymphocytes
    • CD8 proteins – expressed on suppressor or cytotoxic T cells
    • - Associated with Class I MHC molecules
    • CD4 proteins – expressed on helper T cells
    • - Associated with Class II MHC molecules
  7. HIV affects what subset of T cells?
    CD4 Helper T cells
  8. What are criteria (CD4 cell count) for diagnosis of AIDS?
    CD4 count < 200 = diagnosis of AIDS
  9. What cell surface antigens are routinely identified prior to tissue transplantation and why? (p.8)
    • Histocompatibility for HLA – HLA-A, HLA-B, HLA-DR
    • Class I antigens involved in transplant rejections
Card Set
Pathophys Test 2