First, a short question on IgA:
Q. I heard in lecture that IgA is bactericidal. How does that work, if IgA doesn’t bind to complement and does not have an available Fc receptor?
A. Good question. It is true that IgA does not bind complement. It is also true that IgA does not bind to immune cells by its Fc region. So the traditional types of antibacterial activity are not seen with IgA. However, IgA is a secreted immunoglobulin. When combined with lysozyme that is present in some secretions, like saliva, it does possess bactericidal activity against Gram-negative organisms.
1. When the innate immune system encounters a foreign antigen, what cell-surface molecule plays the role of recognizing the presence of a foreign antigen?
b. T cell receptor
c. The membrane attack complex of complement
d. Toll-like receptor *
e. HLA Class II
2. Binding of mannose-binding lectin to mannose-containing molecules on an antigen’s surface _____.
a. inactivates the complement cascade before it can do damage to host cells.
b. activates T cell proliferation and differentiation.
c. activates B cell proliferation and differentiation.
d. directly causes the release of histamine.
e. is an example of pattern recognition.*
3. Naïve CD4+ T cells _____.
a. are also known as cytotoxic T cells.
b. respond to IL-1 + IL-12 to become T1 helper T cells.*
c. respond to antigen presented by HLA Class I molecules.
d. are stimulated to rearrange the DNA for their T cell receptors in the bone marrow.
e. strongly respond to polysaccharide antigens.
4. The part of an antigen that is recognized by the adaptive immune system is called _____.
a. an epitope.*
b. an isotype.
c. a paratope.
d. a cytokine.
e. a chemokine.
5. Which part of the IgE antibody is responsible for binding to mast cells and basophils?
a. Light chain
b. Immunoglobulin fold
c. Fc region *
d. Complementarity-determining region
e. Complement binding site
6. Which of the following bonds is NOT responsible for linking an antibody to its cognate region of an antigen?
a. Van der Waals forces
b. Hydrophobic forces
c. Hydrogen bonds
d. Ionic bonds
e. Disulfide bonds *
7. Antibodies to Streptococcus pyogenes attack certain proteins in the heart valves, causing rheumatic fever. This is an example of _____.
a. an autoimmune disease.
c. passive immunization.
d. neutralization of antigens.
e. an immunodeficiency disease.
8. Two antibodies that have the same antigenic recognition sequence are called _____.
9. Identify the TRUE statement about T cell receptors on αβ T cells.
a. The T cell receptor is composed of a common α subunit and a unique β subunit.
b. The β subunit of T cell receptor is the product of rearranged V, D, and J segments that are combined with a constant region.*
c. The T cell receptor has a signal transduction region on its cytoplasmic side.
d. The T cell receptor on a given T cell will recognize all MHC molecules.
e. On average, a T cell receptor binds to its cognate antigen peptide more firmly than an antibody binds to its cognate antigen peptide.
10. Diversity of T cell receptors is increased by _____.
a. binding to different MHC receptors.
b. somatic cell mutations after T cell activation.
c. addition of N nucleotides at recombination junction sites.*
d. rearranging both beta chains of the T cell receptor at the same time.
e. combination of the beta chains of the T cell receptor with different forms of the CD3 complex.
11. Which of the following is true regarding MHC Class I molecules?
a. Multiple types of MHC Class I molecules can be expressed on a given cell.*
b. Each MHC Class I molecule binds to its own specific cognate antigen protein.
c. MHC Class I molecules can bind their antigen peptides more tightly than antibodies bind to their antigen peptides.
d. MHC Class I molecules can be expressed only on professional antigen-presenting cells.
e. MHC Class I molecules exhibit greater diversity than antibodies.
12. Identify the TRUE statement about MHC molecules.
a. T cells can recognize antigen bound to either self or non-self MHC.
b. MHC Class II is composed of one unique alpha chain and the common beta2 microglobulin chain.
c. MHC Class II is recognized by CD8+ T cells.
d. MHC Class I has the primary role of recognition of self-peptides.*
e. MHC Class I is expressed on a given T cell as either the cassette of MHC inherited from mom or as the cassette of MHC inherited from dad.
13. Dendritic cells _____.
a. constitutively express Class II antigens and B7.*
b. constitutively express Class I antigens but not B7.
c. constitutively express Class II antigens but not B7.
d. constitutively express B7 but not Class II antigens.
e. constitutively express Class II antigens but not Class I antigens.
14. Class II antigens present antigen peptides that _____.
a. have been digested by passing them through a proteasome.
b. have been transported through the endoplasmic reticulum by the TAP1/TAP2 dimer.
c. have been kept appropriately folded by Calnexin.
d. have been placed into the peptide groove on the CD1 chain of the MHC molecule.
e. have been loaded onto MHC by replacing CLIP.*
15. T cells mature in the thymus. Their maturation is driven by the ______ protein that is expressed by stromal cells in the thymus.
a. zeta protein of CD3
d. Notch *
16. Superantigens _____.
a. bind in the antigen-binding cleft of MHC Class I.
b. bind in the antigen-binding cleft of MHC Class II.
c. bind to non-antigen-specific regions of MHC and TCR.*
d. trigger clonal anergy.
e. activate Th1 cells that recognize the cognate antigen present on the superantigen.
17. In the direct antiglobulin test, _____.
a. antibody serves as the index molecule.
b. RBC’s serve as the indicator.*
c. Rh factor serves as the indicator.
d. fluorescence antibody serves as the agent detected.
e. enzyme-linked antibody serves as the agent detected.
18. Which of the following procedures or tests allows the identification and collecting of a particular type of cell that has been recognized by labeled antibody?
a. Western blot
c. Fluorescence-activated cell sorting *
e. Immunofixation test
19. A given macrophage producing IL-1 can induce cells in the brain to reset the body thermostat to a higher temperature. This represents ______ action of a cytokine.
b. endocrine *
20. The ability of several different cytokines to exert a similar activity is called ______.
a. redundancy *
e. transmembrane alteration
21. Identify the cytokine that is responsible for early development of B cells in the bone marrow. In its absence, B cells do not develop.
d. IL-7 *
22. Ig-α/Ig-β signaling in B cells is similar to CD3 signaling in T cells. Their signaling involves activation of _____ on their cytoplasmic tail.
b. ITAM *
d. Phospholipase C
* Note: The beautiful sculpture in the image above represents the BLyS (pronounced bliss) protein which stimulates lymphocyte proliferation, allowing production of antibodies in a mounting immune response.
- Kristine Krafts, M.D. Assistant Professor, Department of Pathology University of Minnesota School of Medicine May 2013: 81,433 unique visitors.
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