For this first section, circle the letter that precedes the best answer for each of the following multiple-choice questions. LOOK AT ALL ALTERNATIVES BEFORE CHOOSING YOUR ANSWER. 1. The TcR (T cell receptor) is an essential element of T cell interactions with: a. soluble proteins floating in the serum b. CD45 molecules c. molecules presented to the T cell in the context of MHC class I or class II molecules d. cell surface molecules expressed on gram negative bacteria e. viral capsid proteins on intact viral particle 2. Signaling through the TcR initiates a cascade that relies upon multiple enzymatic steps. Biochemical events that occur during the signal transduction cascade include: a. protein kinase activation b. protein tyrosine phosphatase activation c. IL-2 activation d. nuclear factor redistribution e. all of the above 3. There are three different ways in which the complement cascade can be activated. These separate pathways to activation are: a. the classical, lectin-mediated, and the alternate pathways. b. the humoral, innate, and the cellular pathway c. the immediate, acute, and the delayed hypersensitivity pathways. d. the primary, secondary and the tertiary immune response e. the ben and jerry response with an ice cream headache chaser. 4. Complement activation has a variety of consequences. Active subunits of complement can result in the: a. establishment of a chemotactic gradient b. opsonization of cellular targets c. disruption of membrane integrity d. damage to nearby normal tissues e. all of the above 5. The Major Histocompatibility Complex is a cluster of linked genes, many of which with importance to immune function. The types of genes found in the MHC do NOT include: a. class I genes b. class II genes c. complement genes d. Ig H chain genes e. any of the above 6. 1. Which of the following is NOT a component of MHC class I molecule? a. An α polypeptide chain b. A β polypeptide chain c. A transmembrane domain d. A small cytosolic domain e. A β2 microglobulin domain 7. The MHC class I gene products combine to form an antigen presenting platform that: a. binds to small peptides of about 8-10 amino acids in length b. interacts with the T cell receptor in the thymus during negative selection c. is expressed on almost all cells. d. displays endogenous antigens e. all of the above are true 1/7
8. Where do the pre-t cells originate that migrate to the Thymus? a. liver b. bone marrow c. spleen d. lymph nodes e. peer s patches 9. Dual recognition as defined by Zinkernagel and Doherty showed that: a. T cells must recognize antigen from tumor cells b. macrophage phagocytosis results in tumor cell killing c. cytokine binding to cytokine receptors depends on both the cytokine and the receptor d. T cell receptor recognition of antigen occurs in the context of the MHC determinant e. either CD4 or CD8 are required as co-receptor for the T cell 10. Immature CD4+, CD8+ double positive T cells that have a TcR (T cell receptor) which recognize self antigens are eliminated in the thymus through which process: a. cytotoxic T cell killing b. negative selection c. positive selection d. necrosis 11. What components make up the ZAS formulation used to initiate chemotaxis? a. Yeast and serum b. Zap70 and serum c. G protein coupled receptors. d. Chicken soup e. All of the above 12. Interleukins are the class of cytokines that a. are produced by red blood cells b. are signals between different leukocytes c. the aging process in white blood cells d. are responsible for the process of positive regulation in the thymus e. activate macrophage phagocytosis in the presence of complement 13. Th1 and Th2 cells can be distinguished from one another by a. the expression of specific differentiation antigens on the plasma membrane. b. the speed with which they proliferate in response to antigen stimulation c. the fact that the Th1 cells make IL-2 while the Th2 cells make IL-4 d. the fact that the Th1 cells stimulate endocrine function while the Th2 cells stimulate paracrine function e. the fact that Th1 cells are immortal while the Th2 cells have limited lifespan 14. The establishment of the T cell response can result in a. the immediate synthesis of nuclear binding proteins such as NF-kB and c-fos b. the early synthesis of gamma-interferon and IL-2 cytokines c. the later synthesis of cell surface molecules such as MHC and adhesion molecules d. all of the above 15. Apoptosis is a critical form of cell behavior. When cells undergo apoptosis a. they die b. they form vesicles (blebs) on the plasma membrane 2/7
c. they can fragment their DNA into multimers of 200 bp pieces that can form "ladders" in an electrophoretic field d. all of the above 16. If a patient suffering from agammaglobulinemia (the absence of secreted Ig in the serum) developed an intracellular bacterial infection, what immunological mechanism could the patient use to eliminate the infection? a. classical complement fixation and activation b. induction of CTLs c. production of cytokines d. generation of IgG to bind and opsonize the bacteria 17. What kinds of epitope prediction would be most useful in designing a vaccine against an extracellular bacterial pathogen? a. A T cell epitope b. A small hapten epitope c. A B cell epitope d. A macrophage-specific epitope e. None of the above 18. Why are people that carry CCR5 chemokine receptor mutations not found to have a serious immune phenotype? a. The complement cascade has three initiation points for activation. b. Cytokines can have redundant and pleiotropic effects. c. The MHC is always polymorphic. d. Immunoglobulins can replace chemokines. e. All of the above (A-D) are true. 19. In the chicken soup chemotaxis paper, components of chicken soup can inhibit neutrophil chemotaxis in vitro. The authors use the Boyden chamber assay to assess the influence on chemotaxis initiated by the known chemoattractants such as ZAS and fmlp. How is the Boyden chamber assay able to measure chemotaxis? a. It provides a clear optical path to see cells as they move toward the chemoattractant. b. The cells that chemotax provide an increased level of chemokines to be measured c. Boyden chambers can assess cellular refraction d. Boyden chambers separate cells from the chemoattractant by a semi-permeable membrane through which the responding cells can crawl e. Boyden chambers present chemoattractant to the cells in a uniform concentration in the media surrounding the cells 20. During the process of apoptosis, what changes mark the exterior of the cell that can be detected by flow cytometry? a. There is an increase in MHC class I expression b. There is a decrease in MHC class II expression c. The phosphatidyl serine (PS) that is usually on the internal leaflet of the membrane flips to the outside d. There is de novo expression of CD45 e. There is a shift in CD4 and CD8 expression 21. Which is a false statement about the K, I, S, and D regions of the Major Histocompatibility Complex in mice? 3/7
a. All 4 regions are encoded the same chromosome b. The I region is only expressed on antigen presenting cells c. Genes in the S region encode serum proteins such as complement proteins d. K and D encoded proteins are present on almost all cells e. All of the above statements (a-d) are true 22. Pattern recognition receptors (PRRs) are important in the following processes: a. Adaptive immunity b. Cytotoxic T Lymphocyte killing c. The response to microbe-associated molecular patterns (MAMPs) d. B and C are correct e. All of the above are true 23. What is correct sequence of events during CTL killing of a target cell infected with flu virus? a. bleb formation, conjugate formation, cell:cell interface vesicle reorientation, apoptosis, fusion and release of vesicle b. conjugate formation, cell:cell interface vesicle reorientation, bleb formation fusion and release of vesicle, apoptosis c. conjugate formation, apoptosis, cell:cell interface vesicle reorientation, bleb formation, apoptosis, fusion and release of vesicle d. conjugate formation, cell:cell interface vesicle reorientation, fusion and release of vesicle, bleb formation, apoptosis e. bleb formation, cell:cell interface vesicle reorientation, fusion and release of vesicle, conjugate formation, apoptosis 24. Dephosphorylation on tyrosine residues of cytosolic proteins a. Is always a positive regulator of the signal transduction cascade b. Can be either a positive or negative regulator of signaling in the process of cellular activation c. Produces a release of calcium from the cell s plasma membrane d. Stimulates complement activation e. None of the above are true 25. Toxins that are secreted by bacteria and interact with host cell surfaces are called: a. Endotoxins b. Cytotoxins c. Exotoxins d. Immunotoxins e. Chemotoxins 26. Microbe associated molecular patterns (MAMP) are specifically important for a. Adaptive immunity b. Innate immune function c. Cytotoxic T cell killing d. The specific assembly of the membrane attack complex e. Serine protease (granzyme) activity 27. When most T cells reach the point of terminal differentiation in the thymus, they a. Express either CD4 or CD8 b. Constitutively express cytokines c. Are no longer expressing TcR molecules d. Can be activated by MHC binding to TcR without a co-stimulatory molecule e. All of the above (A-D) are true. 28. What is an important consequence of calcium release from intracellular stores in T cells after TcR engagement? 4/7
a. The calcium can activate protein kinase C (PKC) b. The calcium changes the cytosolic ph c. The calcium will increase the tightness of the binding of the TcR to its partner MHC/peptide complex d. The calcium will increase the activity of zinc finger protein binding to DNA e. All of the above are true 29. What small polypeptide is part of the MHC class I structure? a. Lysozyme b. Olifactory chemosignals c. The transporter of antigenic peptides (TAP) d. Complement subunit C3 e. Beta2 microglobulin 30. Activation of a classical complement cascade results in lysis of a nearby membrane because a. there is a membrane insertion of the membrane attack complex that forms b. there is activation of apoptotic cascades c. there are changes in ionic distribution and hypotonic lysis d. there is activation of serine proteases e. all of the above (a-d) are true For the next questions, provide brief phrases or sentences to answer the question (do this on the question sheet) 31. Describe two different ways in which viral pathogens can alter the genes that regulate their antigenic structure. a. b. 5/7
32. In the hunt for genes that encode the T cell receptor, Hedrick and Davis made three critical assumptions. Each assumption had to be true for their experimental strategy to select cdna clones that encode antigen specific parts of the TcR to work. Briefly describe each of these assumptions. a. b. c. 33. Draw the immune synapse at the plasma membrane that occur between a T h cell and an antigen presenting cell (APC) that has phagocytized viral particles that had been clumped by antibody and label all of the participating molecules, including the viral peptide antigen. Specifically draw the molecular structures that will initiate the signal transduction cascade in the effector cell that results in the activation of the T h cell to provide help. Be sure to indicate the accessory molecule that stabilizes the interaction at the plasma membrane. Do not draw in the intracellular molecules of the signal transduction cascade. Th cell APC 6/7
34. Why is a person with a genetic defect in C3 complement structure at risk for bacterial infection? 35. What is the hygiene hypothesis? 7/7