Micro I10, I11, I14

  1. True/False: Bacteria and other antigens must be phagocytosed by APCs in the peripheral tissue in order to reach lymph nodes and activate the T cells.
    False: They can also passively diffuse into the lymph vessels and travel to nodes, where macrophages and B cells endocytose them.
  2. Effective B cell activation begins with what kind of interaction with bacterial antigens?
    Crosslinked interaction (must involve several BCRs to activate the cell)
  3. In B cell activation, the Syk kinase signal is analogous to what kinase signal in T cells?
    Zap70. Both will trigger production of NFAT, NF-kappaB, and AP-1.
  4. What type of MHC receptor do B cells use to present peptide antigens to CD4+ T cells?
    Class II (CD4+ cells are Th cells, which always use MHC class II receptors.)
  5. Are intracellular peptide antigens presented using MHC class I or II receptors?
    Class I (All cells express class I so that they can defend against intracellular antigens. Only professional APCs express class II extracellular).
  6. Ig switching in B cells refers to changing to any type of Ig other than:

    C) IgM
  7. Differentiation of B cells requires Th mediation via what two signal molecules?
    CD40 and cytokines
  8. In a primary B cell response to infection, which type of immunoglobulin is detected int he serum first: IgM or IgG?
    IgM. This is detected ~1wk after the onset of infection. IgG is not detected until ~10days.
  9. What are some of the T-cell mediated features which are lacking in a T-Independent (TI) immune response?
    • Only IgM is formed since there is no class switching
    • No somatic hypermutation or affinity maturation
    • No production of memory B cells.
  10. Maternal IgG crosses over the placenta into the fetus. Is this movement specific or non-specific transport?
    It is specific. The FcRB binds IgG and facilitates its movement.
  11. How does Interferon type I work to prevent viral infection?
    It helps inhibit viral replication in cells, and causes increased expression of class I MHCs on infected cells.
  12. True/False: One example of a primary immunodeficiency would be a spontaneous mutation in a previously healthy soldier resulting in Hodgkin's lymphoma.
    False: neoplasm is a secondary immunodeficiency. Primary immunodeficiencies refer to genetic (ie congenital) deficiencies.
  13. A B cell deficiency would lead to increased susceptibility to infection by

    B) extracellular bacteria
  14. X-linked Agammaglobulinemia (XLA) is a genetic deficiency of what type of immune cell?
    B cells
  15. What is the difference in immunoglobulin deficiency between XLA and X-linked Hyper-IgM syndrome?
    In XLA, there is no IgM, IgG, or IgA present in the serum (B cells do not develop). In XLHS, there are no IgG or IgA, but IgM is greater than normal (no class-switching due to lack of CD40 ligand in T cells.)
  16. X-linked SCID results in what immunological phenotype regarding B, T and NK cells?
    B+, T-, NK- phenotype.
  17. What immune disorder is characterized by defective phagocyte oxidase resulting in failure to produce superoxide anions?
    Chronic Granulomatous Disease
Card Set
Micro I10, I11, I14
Adaptive Immunity III, Immunity to Infection, Immunodeficiencies