OpenStax Microbiology Test Bank Chapter 18: Adaptive Specific Host Defenses

OpenStax Microbiology Test Bank Chapter 18: Adaptive Specific Host Defenses * = Correct answer Multiple Choice 1. Which of the following are the primary cells involved in the adaptive immune system? A. dendritic cells B. eosinophils C. lymphocytes* D. macrophages 2. Antibodies are made up of which of the following? A. carbohydrates B. glycoproteins* C. lipids D. nucleic acids 3. Which molecular fragment on an antigen molecule do antibodies recognize and respond to? A. epitope* B. Fab region C. Fc region D. variable region 4. A molecule that is too small to be antigen is known as a(n) . These molecules are typically associated with . A. adjuvant; allergies B. adjuvant; viruses C. hapten; allergies* D. hapten; viruses 5. Which class of antibody is the most abundant in serum? A. IgA B. IgE C. IgG* D. IgM 6. Which class of antibody provides protection against parasitic pathogens? A. IgA B. IgE* C. IgG D. IgM 7. On an antibody, where do phagocytic cells bind during antibody-mediated opsonization? A. disulfide bond B. Fab region C. Fc region* D. variable region 8. Which MHC class is mostly likely found on macrophages? A. class I B. class II* C. both class I and class II D. neither class I nor class II 9. Which cells do not express MHCs? A. erythrocytes* B. hepatocytes C. intestinal epithelial cells D. leukocytes 10. Which process describes the cross-linking of pathogens by antibodies so the kidney and spleen can filter them from the blood? A. agglutination* B. complementation C. neutralization D. transformation 12. Which complement cascade begins with antibodies binding to a pathogen? A. alternative only B. classical only* C. lectin only D. all three pathways (alternative, classic, and lectin) 13. T cells mature in which location? A. bone marrow B. testes C. thymus* D. thyroid 14. A cell that has been infected with an intracellular pathogen will be targeted for destruction by which type of lymphocyte? A. B cell B. CD4+ regulatory T cell C. CD8+ cytotoxic T cell* D. plasma cell 15. Helper T cells are activated by which of the following? A. MHC class I B. MHC class II* C. either MHC class I or class II D. both MHC class I and class II presenting the same antigen 16. Cytotoxic T cells are activated by which of the following? A. MHC class I* B. MHC class II C. either MHC class I or class II D. both MHC class I and class II presenting the same antigen 17. Which bacterial pathogen species can produce superantigen to trigger toxic shock syndrome? A. Escherichia B. Listeria C. Staphylococcus* D. Yersinia 18. Which of the following is the primary function of B cells? A. to activate T cells B. to phagocytose pathogens C. to produce antibodies* D. to target and destroy cells infected with an intracellular pathogen 19. After antigen presentation and activation, antibodies are produced and secreted by which cells? A. CD4 T cells B. memory T cells C. naïve B cells D. plasma cells* 20. Which of the following is the term for activated B cells producing different antibody monomers with the same epitope specificity? A. class switching* B. clonal expansion C. cross presentation D. VDJ arrangement 21. Which of the following statements is true? A. In the secondary response to an antigen, higher levels of IgM will be detected in an individual’s serum. B. In the secondary response to an antigen, lower levels of IgM will be detected in an individual’s serum. C. The lag period following secondary exposure to an antigen is longer than the lag period following primary exposure. D. The lag period following secondary exposure to an antigen is shorter than the lag period following primary exposure.* 22. B cells mature in which location? A. bone marrow* B. bulbourethral gland C. thymus D. thyroid 23. Which protein released by CD8+ cytotoxic T cells generates pores in target cells? A. granzyme B. hyaluronidase C. perforin* D. phospholipase 24. TCRs recognize epitopes made of which type of molecule? A. carbohydrates B. lipopolysaccharide C. nucleic acid D. protein* 25. Who is credited for the discovery of the concept of a vaccine through his work with cowpox and smallpox? A. Alexander Fleming B. Edward Jenner* C. Joseph Lister D. Louis Pasteur 26. Who is credited for the discovery of the vaccine against cholera? A. Alexander Fleming B. Edward Jenner C. Joseph Lister D. Louis Pasteur* 27. Why was James Phipps (the boy who was purposely infected with cowpox) protected against smallpox? A. Cowpox and smallpox are the same virus. B. Cowpox is antigenically similar to smallpox.* C. He was also inoculated with B cells specific for smallpox when he was infected with cowpox. D. Individuals need to be given a vaccine against only one type of virus to gain protection against all viruses. 28. Vaccines are an example of which class of immunity? A. active artificially acquired* B. active naturally acquired C. passive artificially acquired D. passive naturally acquired 29. Which vaccine would be most protective against diphtheria? A. conjugate B. inactivated C. live attenuated D. toxoid* 30. Which vaccine would be most protective against the capsule-forming pathogen Neisseria meningitidis? A. conjugate* B. inactivated C. live attenuated D. toxoid Difficulty: Hard ASM Standard: 14, 23 True/False 31. The secondary immune response to the same antigen will result in less antibody production. Answer: False Difficulty: Easy ASM Standard: 7, 14 32. An antigen can only have one epitope site. Answer: False Difficulty: Easy ASM Standard: 7, 14 33. It is possible for two different antibodies to recognize the same antigen. Answer: True 34. Antibodies are ineffective against toxins. Answer: False 35. All nucleated cells can present antigens to trigger the adaptive immune response. Answer: True 36. CD8+ cytotoxic T cells can be activated by either MHC class I or cytokines from TH1 cells. Answer: True 37. TCRs are secreted by T cells to target free-floating antigens. Answer: False 38. After exposure to a protein antigen, antibodies will be immediately detectable in an individual’s serum. Answer: False 39. Subunit vaccines do not provide protection against antigenic variation. Answer: True 40. IgM immunoglobulin can cross the blood-placental barrier and is important for natural passive immunity. Answer: False Matching 41. Match each subgroup to its distinguishing feature. A. CD4+ T cell i. destroys cells infected with intracellular pathogens B. CD8+ T cell ii. orchestrates humoral and cellular immunity C. helper T cell iii. produces antibodies D. plasma cell iv. involved in peripheral tolerance and prevents autoimmune diseases. Answers: A. iii., B. iv., C. i., D. ii. 42. Match the type of T cell to its proper description. A. memory i. responsible for the secondary response to a particular antigen B. TH1 ii. stimulates B-cell activation C. TH2 iii. stimulates immunity to chronic mucocutaneous infections D. TH17 iv. stimulates cytotoxic CD8+ T cells Answers: A. i., B. iv., C. ii., D. iii. 43. Match the example to the type of immunity being acquired. A. being ill and recovering from an infection i. artificial active B. blood transfusion from someone previously infected with a pathogen ii. artificial passive C. breastfeeding iii. natural active D. receiving a vaccine iv. natural passive Answers: A. iii, B. ii, C. iv, D. i 44. Match the class of vaccine to its proper description. A. conjugate i. killed or otherwise nonfunctional pathogen B. inactivated ii. inactivated toxin C. live attenuated iii. capsule polysaccharide bound to a protein D. subunit iv. weakened pathogen E. toxoid v. immunogenic antigen of the pathogen Answers: A. iii, B. i, C. iv, D. v, E. ii Fill in the Blank 45. involves the binding of antibodies to epitopes on the surface of viruses to inhibit attachment to host cells. Answer: Neutralization Difficulty: Easy ASM Standard: 14 46. Antibodies consist of four protein chains held together by bonds. Answer: disulfide Difficulty: Moderate ASM Standard: 14 47. is the region that an antibody recognizes and binds to on an antigen. Answer: Epitope Difficulty: Easy ASM Standard: 14 48. The is a collection of molecules expressed on the surface of cells and that present antigens to activate T cells. Answer: major histocompatibility complex (MHC) 49. is when antigens normally presented with MHC II are presented on MHC I for CD8+ cytotoxic T cells. Answer: Cross-presentation 50. Granzymes are proteases made by CD8+ cytotoxic T cells that enter pores generated by to induce apoptosis. Answer: perforin 51. are toxins that can induce a cytokine storm and can lead to toxic shock syndrome. Answer: Superantigens 52. is a reduction in disease prevalence brought about when relatively few individuals in a population are susceptible to an infectious agent. Answer: Herd immunity 53. In 10th century China, individuals were deliberately inoculated with infectious material from smallpox pustules. This type of inoculation is known as . Answer: variolation 54. is the process of making a pathogen less virulent so it can be used as a vaccine. Answer: Attenuation Short Answer 55. What is the difference between an antigen and a PAMP? Sample Answer: An antigen is unique to a specific pathogen, whereas a PAMP (pathogen- associated molecular pattern) can be found on numerous pathogens. 56. Briefly discuss the two primary characteristics of the adaptive immune system. Sample Answer: Specificity and memory are the two primary characteristics of the adaptive immune system. Specificity refers to the immune system’s ability to target specific pathogens and not target host cells (i.e., recognizes and does not target self). Memory refers to its ability to quickly respond to pathogens to which it has previously been exposed. 57. Examine the figure shown below of a secreted glycoprotein. (a) What does this figure depict? (b) Identify each of the following on the diagram: a. Fab region b. Fc region c. disulfide bond location d. antigen-binding site e. complement protein-binding site Sample Answer: (a) an antibody (b) 58. Name the five functions of antibodies. Sample Answer: Neutralization of pathogens, opsonization for phagocytosis, agglutination, complement activation, and antibody-dependent cell-mediated cytotoxicity 59. What is opsonization? Sample Answer: Opsonization is the process of coating a pathogen with a chemical substance (typically an antibody) that allows phagocytic cells to recognize, engulf, and destroy the pathogen more easily. 60. What are the similarities and differences between T-cell receptors (TCRs) and antibodies? Sample Answer: Both have a variable region and a constant region. The variable region provides the antigen-binding site. TCRs are produced by T cells and antibodies are produced by plasma cells. TCRs have two protein chains, whereas antibodies have four protein chains. TCRs are membrane-bound to the T cell, whereas antibodies are secreted. 61. One component of the adaptive immune system is the concept of tolerance. Immune cells should not recognize host (or self) antigens. What mechanisms are available to remove lymphocytes with receptors that do recognize self antigens? Sample Answer: Negative selection of self-reacting lymphocytes can involve elimination by apoptosis and editing or modification of the receptors so they are no longer self-reactive. 62. How is it possible for the immune system to produce receptors (i.e., TCRs, BCRs, antibodies) against a wide variety of antigens, especially when the immune system has not yet encountered them? Sample Answer: The VDJ arrangement allows the immune system to produce receptors against a wide variety of antigens. The variable regions of receptors can recognize different types of epitopes of antigens. The genes that code for the variable regions of receptors are called variable (V), diversity (D), and joining (J) segments. In T-cell receptors, genetic rearrangement brings together one V segment and one J segment to code for the variable region of the α chain. Similarly, genetic rearrangement brings one V segment, one D segment, and one J segment together to code for the variable region of the β chain. In B-cell receptors and secreted immunoglobulins (antibodies), the variable region of the light chain is made up of V and J segments. Genetic rearrangement of V, J, and D segments generate the heavy chain. 63. How is a cytokine storm triggered? Sample Answer: A cytokine storm is triggered by a superantigen. A macrophage presents the superantigen via MHC class II. The superantigen is not recognized by the TCR of the T cell. However, the superantigen can still bind the MHC II and TCR molecules. This nonspecific, uncontrolled activation of the T cell results in an excessive release of cytokines that activate other T cells and cause excessive inflammation. 64. In terms of lymphocyte development, what is meant by clonal expansion? Sample Answer: A lymphocyte with a specific receptor will become active after binding to a presented antigen. That lymphocyte will undergo mitosis to produce more lymphocytes that all share the same antigen specificity. 65. On the axes below, sketch the relative concentrations of IgM and IgG in serum after a primary and secondary response to the same antigen. Sample Answer: See graph below. 66. How was the concept of a vaccine discovered and who discovered it? Sample Answer: Exudates from a cowpox pustule on the hand of a dairymaid (Sarah Nelmes) were inserted into scratches on the arm of an 8-year-old boy (James Phipps) by Edward Jenner. Later, when the boy was purposely infected with smallpox, he did not contract the disease. 67. Against what type of pathogen should a conjugate vaccine be used? Sample Answer: Conjugate vaccines should be used against pathogens that can produce capsules. 68. Explain one advantage and one disadvantage to using live attenuated vaccines. Sample Answer: Advantages include that the pathogen in the vaccine can trigger both cellular and humoral immunity. A live attenuated vaccine also can provide long-lasting immunity. Disadvantages include the challenge of long-term storage, the potential for a patient to acquire the disease (or a milder form of it), and the risk of the attenuated pathogen reverting to full virulence. 69. Explain one advantage and one disadvantage to using subunit vaccines. Sample Answer: An advantage would be that there is a lower risk of side effects because the entire pathogen is not being used in the vaccine. The disadvantages include that there is limited longevity, multiple doses of the vaccine are needed, and there is no protection against antigenic variation. Brief Essay Essay Question Rubric RATING Failing Below Average Competent Advanced Criteria for evaluation Answer does not provide an argument. Answer contains inaccuracies. Writing is poor and contains numerous grammatical mistakes and misspellings. Answer fails to provide examples to support an argument. Writing is poor and grammatical errors are common. Answer is somewhat incoherent. Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings. Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings. POINT VALUE 0 1 2 3 Assume rating/grading scale for the question ranges from 0 to 3 points. 70. Discuss the differences between T and B cells and their receptors. Answer: Student answers will vary but should include the following. The maturation of T cells occurs in the thymus. T cells function in both the innate and adaptive immune responses. They are responsible for destruction of cells infected with intracellular pathogens. The T-cell receptor (TCR) has a variable region and a constant region. The structure of the TCR is smaller and less complex than the immunoglobulin molecules. It only has two peptide chains. T cells are activated by antigen-presenting cells. TCRs can only interact with antigenic epitopes that are presented within the antigen-binding cleft of MHC class I or MHC class II. TCR can only recognize protein epitopes. B cells mature in the bone marrow and produce antibodies. Antibodies are involved in the body’s defense against pathogens and toxins in the extracellular environment. Antibodies and B-cell receptors (BCRs) have two identical heavy chains and two identical light chains connected by disulfide bonds. Antibodies are secreted, whereas BCRs remain attached to the B cell (the constant region of the receptor spans the B-cell membrane). B cells can be activated either with or without T cells. They can interact with epitopes on free antigens or with epitopes displayed on the surface of intact pathogens. Antibodies and BCRs can recognize different molecular classes, not just proteins. 71. Describe how an intracellular pathogen infecting a hepatocyte is targeted and eliminated via the adaptive immune system. Be sure to discuss all the lymphocytes involved. Answer: Student answers will vary but should include the following. After the intracellular pathogen invades the hepatocyte (nonleukocyte), an antigen will be presented on the surface of the cell via MHC class I. CD8+ cytotoxic T cells recognize the foreign epitope and begin to produce cytokines. The cytokines (specifically from TH1 cells) will target clonal expansion of that T cell, with all of them recognizing the same antigen. The proliferation of these cytotoxic T cells is also stimulated by cytokines secreted from TH1 cells, which are also activated by the same antigen. Once activated, cytotoxic T cells serve as the effector cells of cellular immunity, recognizing and killing cells infected with intracellular pathogens through a mechanism similar to that of natural killer cells. TCRs of mature cytotoxic T cells bind to the epitope and release perforin, a protein that creates pores in the target cell. Granzymes are proteases that enter the pores and induce apoptosis. 72. Compare and contrast T-dependent and T-independent activation of B cells. Answer: Student answers will vary but should include the following. Antigens can be classified as T-independent and T-dependent. T-independent antigens have repeating epitopes that can induce B-cell recognition and activation without involvement from T cells. These antigens include polysaccharides, lipopolysaccharides, and other nonprotein antigens. A second signal, such as interaction of Toll-like receptors with PAMPs, is also required for activation of the B cell. Once activated, the B cell proliferates and differentiates into antibody-secreting plasma cells. In T-dependent activation of B cells, the B cell recognizes and internalizes an antigen. T-dependent antigens are typically protein antigens. The antigen is presented to a helper T cell that is specific to the same antigen. The helper T cell interacts with the antigen presented by the B cell, which activates the T cell and stimulates the release of cytokines that then activate the B cell. Activation of the B cell triggers proliferation and differentiation into antibody-secreting plasma cells.