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- Central (primary) lymphoid organs
a. are efficient in exposing T cells to foreign antigen. b. are the primary site of antibody synthesis and release. c. filter blood and trap blood-borne antigens. d. provide the microenvironment for maturation of T and B cells. e. line the mucosal surfaces of the body for efficient antigen contact.
- Hematopoietic stem cells are pluripotent, which means that they are
a. antigen-specific cells. b. capable of developing into any blood cells. c. committed to produce cells of a single lineage. d. not self-renewing. e. T and B lymphocytes of many different antigen specificities.
- Lymphocytes continually recirculate through peripheral lymphoid tissue in order to
a. be killed before they cause autoimmunity. b. efficiently encounter antigen. c. mature from stem cells into lymphocytes. d. phagocytose antigen and kill it. e. go where no cell has gone before.
- Peripheral lymphoid organs
a. are centrally located in the abdomen to protect their vital functions. b. are designed to maximize contact between antigen and lymphocytes. c. produce antigen-specific lymphocytes from stem cells in response to antigen. d. sequester antigen to minimize its damage to the body. e. store large numbers of activated effector cells for a rapid response to antigen.
- The PRIMARY purpose of the adaptive immune system is to
a. block all pathogens from entering the body. b. cure allergic reactions. c. kill tumor cells. d. protect from disease upon re-infection with a specific pathogen. e. reject foreign transplants.
- Rapid but non-antigen specific immune responses are produced by the
a. adaptive immune system. b. innate immune system. c. leukocytes. d. lymphatic system. e. memory response.
- Vaccination protects us from infectious disease by generating memory
a. antigen. b. lymphocytes. c. macrophages. d. PMNs. e. stem cells.
- Which situation below describes an example of innate immunity?
a. antibody production by plasma cells.
b. antigen removal by cilia in the respiratory tract. c. complement activation by antibody bound to the surface of a bacterium. d. memory response to influenza virus e. recognition and killing of virus-infected cells by cytotoxic T cells.
- The antigen specificity of an adaptive immune response is due to
a. activation of antigen-specific lymphocytes. b. folding of antibody to fit the pathogen. c. lysis of only certain pathogens by neutrophils. d. phagocytosis of only certain pathogens by macrophages. e. production of cytokines by antigen-specific macrophages
- Clonal selection
a. begins with inflammation. b. occurs for all leukocytes. c. occurs in response to self antigens. d. results in innate immunity. e. results in proliferation of antigen-specific lymphocytes.
- Cytokines are NOT
a. able to induce increased blood vessel permeability. b. antigen-specific. c. made in response to bacterial antigens. d. signals from one cell that affects the behavior of another cell. e. secreted by macrophages.
- A fundamental difference between the antigen receptors on B cells (BCR) and on T cells (TCR) is their
a. different requirements for antigen presentation. b. function following antigen binding. c. heterogeneity from one lymphocyte to the next. d. heterogeneity on each lymphocyte. e. membrane location.
- Genes for immunoglobulins (antibodies) are unlike other human genes in that
a. antibody genes are composed of introns and exons. b. DNA for antibody molecules is inherited from only one parent. c. gene segments must be spliced together to make each unique antibody molecule. d. several exons encode each antibody molecule. e. none of the above is true.
- Humoral immunity can be acquired passively by
a. catching a virus from a friend by shaking hands. b. receiving a vaccine of influenza virus grown in eggs. c. receiving serum from someone who has recovered from an infection. d. receiving leukocytes from an immune family member. e. sharing a soda with someone who has a cold.
- Inflammation does NOT involve
a. cytokine production by macrophages. b. migration of leukocytes out of the circulation. c. pain. d. secretion of antibodies.
d. opsonizing antibody. e. Th1 cells.
- Phagocytosis
a. can be stimulated by antigen binding to complement or antibody. b. is an antigen-specific process. c. must be preceded by antigen processing. d. rids the body of virus-infected cells. e. only occurs after plasma cells begin secreting antibody.
- Several friends who went on a picnic together developed vomiting and diarrhea from eating potato salad contaminated with Staphylococcus aureus enterotoxin. Effects of the toxin could best be counteracted by
a. antibody binding and neutralization of the toxin. b. antibody opsonization and phagocytosis of S. aureus. c. antibody opsonization and phagocytosis of the toxin. d. B cell binding to S. aureus. e. cytotoxic T cell binding and lysis of S. aureus.
- Which of the following statements is FALSE?
a. An example of passive humoral immunity is treatment with horse anti-snake venin. b. Antigen recognized by helper T cells must be associated with Class II MHC molecules on the surface of professional APC. c. Each lymphocyte has many antigen binding receptors, each receptor capable of binding the same antigen. d. Recognition and killing of virus-infected cells by cytotoxic T cells is an example of adaptive immunity. e. The innate immune system does not deal with endogenous antigen.
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- The ability of an antigen to induce an immune response does NOT depend on the antigen's
a. ability to enter the thyroid. b. degree of aggregation. c. dose. d. size. e. usual presence in the body.
- Alum is an effective adjuvant because it
a. disaggregates the antigen. b. is immunogenic for stem cells c. is immunogenic for T cells. d. slows the release of antigen. e. transports antigen into the cytoplasm of antigen-presenting cells.
- Antibody cross-reactivity is demonstrated by antibody binding to
a. a cell surface marker. b. a hapten. c. a hapten-carrier complex. d. an antigen that is structurally similar to the immunogen e. the immunogen.
- The antibiotic penicillin is a small molecule that does not induce antibody formation. However, penicillin binds to serum proteins and forms a complex that in some people induces antibody formation resulting in an allergic reaction. Penicillin is therefore
a. an antigen. b. a hapten. c. an immunogen. d. both an antigen and a hapten. e. both an antigen and an immunogen.
- Antigen entering the body in a subcutaneous injection activates its specific lymphocytes in the
a. blood circulation. b. draining lymph nodes. c. MALT. d. skin. e. spleen.
- To detect a humoral immune response to influenza virus, you would measure
a. cytotoxicity of virus-infected cells in the lung. b. cytotoxicity of virus-infected cells in tissue culture. c. dividing T cells in the draining lymph nodes. d. plasma cytokine levels. e. serum antibody titer.
- During the lag period between antigen contact and detection of adaptive immunity,
a. antigen is hidden from the immune system in macrophages. b. cellular immunity can be detected but antibodies cannot. c. innate immune effectors are eliminating antigen. d. innate immunity blocks the activation of adaptive immune effector cells. e. new B and T cells with the appropriate antigen specificity must be produced in the bone marrow.
- To elicit the best antibodies to mouse MHC I, you should inject it into
a. a goat. b. a mouse of the same genetic background (strain). c. a mouse of a different strain. d. a rat. e. the mouse you isolated it from.
- For specific antigen recognition by T cells,
a. antigen is bound by a T cell membrane antibody. b. denaturation of antigen does not reduce epitope recognition. c. MHC molecules are not required. d. soluble antigen is bound directly without processing. e. antigen exposure during T cell maturation is required.
- The immune response to a booster vaccine is called a(n)
c. foreign MHC. d. live virus. e. virus peptides.
- Which statement about antigen epitopes is FALSE?
a. An epitope may be shared by two different antigens. b. A protein molecule usually contains multiple epitopes. c. B cells bind only processed antigen epitopes. d. Epitopes may be linear or assembled. e. Some epitopes are more immunogenic than others
- CD antigens
a. allow leukocytes to recognize antigen. b. are each expressed on only one cell type. c. are expressed on immune cells by immunologists to "mark" them for separation. d. are found only on leukocytes. e. function as receptors for cytokine and CAMs.
- A patient desperately needs a bone marrow transplant, and a perfect match cannot be found. The rejection response in unmatched marrow is primarily due to the presence of mature T cells that recognize the recipient's cells as foreign. To minimize this rejection response, the marrow can be treated before transfusion into the recipient with complement plus antibody to human
a. CD3. b. CD4. c. CD8. d. CD28. e. CD154.
- Antibody to membrane receptors sometimes inhibits receptor function and sometimes mimics the action of the normal receptor ligand. (For example, some antibodies to insulin receptor block the action of insulin and some mimic the action of insulin.) An antibody which should NOT either block or stimulate B cell function would be anti-
a. CD21. b. CD56. c. CD80. d. Iga. e. m chain.
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- Cytokines may exhibit __________ action, signaling the cells that produce them.
a. antagonistic b. autocrine c. endocrine d. paracrine. e. synergistic
- Cytokines are NOT
a. antigen specific. b. capable of activating more than one cell type. c. made by lymphocytes. d. small protein molecules. e. synthesized de novo in response to antigen or other cytokines.
- Several cytokines may have the same effect on the cells they bind. This is an example of
a. a cascade. b. antagonism. c. pleiotropism. d. redundancy. e. synergy.
- Characterization of cytokine activities is NOT made more difficult by their
a. gene structure. b. pleiotropism. c. redundancy. d. secretion close to target cell membranes. e. short half-lives.
- Interferons
a. activate B cells to make virus-specific antibodies. b. are Th2 cytokines. c. are virus proteins that interfere with activation of cytotoxic T cells. d. block virus infection of host cells. e. inhibit virus replication by infected cells.
- A cytokine can do all of the following EXCEPT
a. bind to receptors which do not share cytokine-binding subunits. b. bind to its specific receptor on the same cell that produced it. c. bind to receptor antagonists produced by pathogenic viruses. d. compete with other cytokines whose receptors share signal-transducing subunits e. upregulate (increase) synthesis of high affinity subunits for its receptor.
- Members of a cytokine receptor family
a. all bind the same cytokines. b. are grouped together because they share antigen specificity c. are often found on the same cells d. are similar in protein structure and sometimes in regions of amino acid sequence. e. are specific for cytokines produced by a single cell type
- The ability of a cytokine to change gene expression in the target cell is influenced by all of the following EXCEPT
a. presence of high-affinity receptors on the target cell.
b. is secreted by macrophages and hepatocytes in response to antigen binding. c. participates in both innate and adaptive immune responses. d. prevents lysis of virus-infected cells. e. All of the above statements about complement are true.
- Complement is involved in all of the following except
a. attraction of neutrophils to an infection site. b. increased presence of serum proteins in the infected tissues. c. lysis of bacteria in the absence of specific antibodies. d. opsonization of microorganisms for phagocytosis. e. sensitization of T cells to antigen
- Complement is
a. activated by binding to specific complement receptors. b. antigen-specific. c. a potent promoter of virus entry into host cells. d. a series of intracellular proteins which work with antibody to eliminate endogenous antigen. e. present in the circulation in an inactive form.
- The alternative pathway of complement activation
a. causes tissue damage in the absence of C1INH. b. occurs after the classic pathway is activated. c. occurs only if the classical pathway is ineffective in pathogen clearance. d. requires C3. e. requires C4.
- If a person is born without C2 and C4,
a. C5 can still be cleaved by the classical pathway. b. C3b will not be able to bind to bacteria. c. C9 will polymerize inappropriately and lyse host cells. d. the classical pathway will be changed into the alternative pathway. e. the amount of C3b produced during bacterial infections will be reduced.
- Which of the following are least sensitive to complement-mediated lysis?
a. Enveloped viruses b. Erythrocytes c. Gram negative bacteria d. Gram positive bacteria e. Leukocytes
- In the membrane attack phase of the classical complement pathway, the role of C5b is to
a. activate the C5 convertase activity. b. attract neutrophils to lyse the pathogen. c. initiate formation of the MAC. d. polymerize into a membrane-spanning channel. e. All of these are activities of C5b.
- Complement receptors (CR)
a. activate complement on the surface of pathogens. b. bind only activated complement proteins. c. inhibit complement activation on the surface of host cells. d. on erythrocytes remove immune complexes from the circulation. e. on macrophages signal host cells to make opsonins.
- As complement is activated by complexes of antibody-coated bacteria, bystander lysis of nearby host cells is prevented by
a. a long-lived thioester bond on active complement proteins. b. covalent attachment of all active complement proteins to the pathogen surface. c. plasma proteins that inactivate the anaphylatoxins. d. proteins on host cell membranes that inhibit MAC formation. e. the slow catalytic rates of complement proteases.
- Complement activity is restricted by all of the following EXCEPT
a. dissociation of C3 and C5 convertases. b. Gram positive cell walls that are resistant to MAC polymerization. c. host cell plasma proteins that inactivate C3a, C4a, and C5a activity. d. LPS in the outer membrane of Gram negative bacteria that inactivates C3b. e. proteolytic cleavage of complement proteins into smaller fragments.
- A deficiency in complement proteins or in their regulators can result in
a. blood in the urine from erythrocyte lysis. b. decreased levels of certain complement proteins in the circulation. c. immune complex disease. d. increased numbers of infections. e. All of the above can result from complement deficiencies.
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- Phagocytosis must be preceded by
a. antigen binding to the phagocyte. b. chemotaxis. c. extravasation. d. integrin binding to Ig superfamily CAMs. e. oxidative burst.
- Phagocytes bind antigen using receptors for
a. C5a. b. chemokines. c. glucose. d. LPS. e. selectins.
c. include ICAM, VCAM, and MAdCAM. d. select antigen-specific lymphocytes to extravasate into the infection site. e. select antigen-specific macrophages to extravasate into the infection site.
- Lymphocyte recirculation
a. activates inflammatory cytokines to promote antigen presentation to T cells. b. allows B cells to go to the site of infection to produce antibody. c. circulates lymphokines efficiently throughout the body. d. occurs for both naïve and effector lymphocytes e. only occurs during an infection.
- Phagocytes kill bacteria using all of the following EXCEPT
a. H2O2. b. hydrolytic enzymes. c. low pH d. lysozyme. e. strong reducing agents.
- For a circulating neutrophil to reach the site of inflammation, it must bind to blood vessel endothelial cell and then pass between the endothelial cells in a process called
a. addressinazition. b. chemotaxis. c. extravasation. d. marginalization. e. opsonization.
- Macrophages are attracted to the site of infection by all of the following EXCEPT
a. bacterial peptides. b. chemokines. c. C5a. d. IL-8. e. MAdCAM.
- Inflammatory cytokines produced by macrophages activate all of the following EXCEPT
a. B cells to secrete acute phase proteins. b. integrin on leukocytes to bind more strongly to vascular CAMs. c. neutrophils to be more cytotoxic. d. NK cells to kill virus-infected cells. e. vascular endothelium to increase expression of CAMs.
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- An antibody Fab contains
a. complementarity determining regions. b. H and L chain variable regions. c. one antigen binding region.
d. one H-L interchain disulfide bond. e. all of the above.
- Myeloma proteins are
a. abnormally formed antibodies secreted from cancerous plasma cells. b. cancerous plasma cells that divide without requiring antigen activation. c. cell lines that secrete specific antibodies for a short time, then die. d. homogeneous antibody molecules secreted by plasma cell tumors. e. protein signaling molecules that make a plasma cell become a multiple myeloma.
- The regions of the antibody molecule which contribute MOST to the affinity of the antibody for antigen are the
a. CDR. b. Fab regions. c. Fc regions. d. framework regions. e. hinge regions.
- Antibody Fc fragments contain
a. antigen-binding sites. b. CDR. c. complement-binding sites. d. framework residues. e. light chain variable domains.
- The immunoglobulin isotype is determined by the
a. antigen specificity. b. H chain constant region. c. L chain variable region. d. number of antigen-binding sites. e. number of VH domains.
- Which statement about antigen epitopes is FALSE?
a. An epitope may be shared by two different antigens. b. A protein molecule usually contains multiple epitopes. c. B cells bind only processed antigen epitopes. d. Epitopes may be linear (composed of sequential amino acids) or assembled by protein folding from amino acids far apart in the protein primary amino acid sequence. e. Some epitopes are more immunogenic than others.
- An example of an antigen epitope from an infectious organism would be
a. a bacterial endotoxin (LPS) molecule. b. a fungal cell wall protein. c. a peptide on the surface of a virus capsid protein. d. a whole virus. e. All of the above are antigen epitopes.
d. l chain. e. secretory component.
- You have purified some Fab from an IgG myeloma protein. Under appropriate conditions, you could use this Fab to generate antibodies to
a. both k and l chain. b. g chain hinge region. c. J chain. d. g chain allotypic determinants. e. the idiotype of this myeloma.
- The Ig isotype which would be most important for neutralizing polio virus before it could infect intestinal cells would be
a. secretory IgA. b. serum IgA. c. serum IgD. d. serum IgG. e. membrane IgM.
- Which of the following changes to a serum IgM antibody molecule would definitely DECREASE its avidity?
a. Increase noncovalent antigen-antibody interactions in the CDR. b. Remove the secretory component. c. Replace the Fc portion of the mu chains with the Fc portion of alpha chains. d. Replace VH and VL framework regions with those from a different antibody. e. Use limited enzyme digestion to make Fab fragments.
- IgA can be secreted from the body because it
a. binds poly-Ig receptor on mucosal epithelial cells. b. has a specialized H chain called secretory chain. c. has a special secretory idiotype. d. is small enough to pass between mucosal epithelial cells and leave the body. e. is synthesized by mucosal epithelial cells and secreted directly into the intestinal lumen.
- The ability to make antibody with the same antigen specificity but different Fc regions
a. causes allelic exclusion of Ig molecules. b. does not occur against bacterial antigens. c. improves the antigen binding specificity of an Ig molecule. d. increases the effector functions of Ig molecules. e. requires clonal elimination.
- Allergy symptoms are produced when antigen binds to IgE on FcR on
a. A cells. b. macrophages. c. mast cells.
d. neutrophils. e. Th1 cells.
- One amino acid difference in the Fc region of different human g chains is the epitope recognized by anti-
a. allotype. b. idiotype. c. isotype. d. IgG. e. g chain.
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- Genes for immunoglobulins are unlike other human genes in that
a. each polypeptide chain is encoded by several exons. b. Ig genes are composed of introns and exons c. somatic recombination occurs before mRNA is transcribed d. there is less Ig genetic material in mature B cells than in other somatic cells e. both c and d are true.
- The gene segments needed to encode the variable region of a k chain are
a. one Jk plus one Dk. b. one Jk plus one Ck. c. one Vk plus one Dk. d. one Vk plus one Jk. e. one Vk plus one Jk plus one Dk.
- Pseudogenes are DNA sequences which look very similar to functional genes except for the presence of a(n)
a. intron. b. leader sequence. c. promoter codon. d. signal sequence. e. stop codon.
- Combinatorial diversity says that by random combination of 40 functional Vk segments with five Jk segments, the number of possible different k chains that could be made are
a. 40. b. 45. c. 70. d. 200. e. 1200.
- Which does NOT contribute to Ig antigen-binding diversity
a. Any L chain can combine with any H chain to form a functional antibody. b. Any Vk can be joined to any Jk to encode the light chain V region. c. Many CH genes are present in the germline DNA. d. Random numbers of N nucleotides can be added during somatic recombination.
a. are catalyzed by the products of RAG1 and RAG b. are regulated by helper T cell cytokines. c. can result in stop codons in coding sequences. d. occur in developing B cells in the bone marrow. e. result in the irreversible loss of DNA from the B cell.
- Alternative mRNA splicing
a. allows the B cell to improve its antigen-binding fit after antigen contact. b. allows the B cell to make membrane IgM from the mature mRNA for secreted IgD. c. can be used for the simultaneous production of any two Ig isotypes. d. is a process by which a B cell can simultaneously synthesize m and d chains. e. occurs in response to T cell cytokines.
- Because of the order of the CH gene segments (Cm, Cd, Cg3, Cg1, pseudogene Ce, Ca1, Cg2, Cg4, Ce, and Ca2), a human B cell which undergoes isotype switching from IgM to IgG1 can never in the future secrete
a. IgA. b. IgE. c. IgG2. d. IgG3. e. IgG4.
- Isotype switching is always productive because
a. B cells produce all isotypes simultaneously. b. isotype switching does not involve recombination of DNA gene segments. c. no DNA is deleted from the chromosome in isotype switching. d. no effector diversity results from isotype switching. e. recombination between switch sites occurs in introns so it cannot introduce stop codons into coding regions.
- Somatic hypermutation does NOT
a. occur by somatic recombination. b. occur during B cell proliferation. c. occur in the B cell following antigen stimulation. d. result in increased affinity of antibodies secreted later in immune responses. e. result in the death of some B cells which no longer bind antigen.
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- Which of the following is NOT True about TCR?
a. All TCRs on a particular T cell have identical idiotypes. b. CDR3 of TCR has the most sequence variability from molecule to molecule. c. TCR has binding sites for both antigen and self MHC. d. TCR is a disulfide-bonded heterodimer. e. The ab or gd isotype of TCR determines the biological function of its secreted form.
- The antigen-binding region of TCR is formed by the folding of
a. Va and Vb chains. b. Va, Vb, and CD3 chains. c. Va and Vb2-microglobulin chains. d. Vg and Va chains. e. VL and VH chains.
- Which of the following properties are NOT shared by TCR and BCR?
a. Antigen-binding avidity is increased by the presence of two antigen binding regions on each receptor. b. Antigen-binding diversity is generated through gene rearrangement. c. Folding of protein domains is maintained by intrachain disulfide bonds. d. Membrane expression and lymphocyte activation by antigen require receptors to be associated with signal transduction molecules. e. Receptor antigen-binding sites are formed from two polypeptide chains.
- TCR most closely resembles
a. Class I MHC. b. Class II MHC. c. Fab region of immunoglobulin. d. Fc region of immunoglobulin. e. light chain of immunoglobulin.
- Rearrangement of both TCR and BCR gene segments does NOT
a. generate diversity of antigen binding by recombination of a large pool of germline V, D, and J segments. b. lead to CDR3 being the most hypervariable region in the receptor chains. c. require RAG-1, RAG-2, and TdT expression. d. result in allelic exclusion of membrane receptors. e. result in isotype switching after antigen stimulation of the mature lymphocytes.
- The amount of diversity in TCR generated within one individual by somatic recombination
a. is higher than BCR diversity. b. is about the same as for BCR diversity. c. is lower than BCR diversity. d. is lower than Class I MHC diversity. e. is lower than Class II MHC diversity.
- T cells use all of the following for generating antigen-recognition diversity on the TCR, except
a. combinatorial association of chains. b. combinatorial association of segments. c. large germline pool of gene sequences. d. N region addition of nucleotides. e. somatic hypermutation.
- CD8 is a co-receptor on T cells that binds
a. CD3. b. endogenous antigen peptide. c. the constant region of Class I MHC.
