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Home , Central tolerance, Epitope, Isotype (immunology), Peripheral tolerance, Somatic hypermutation

MICROBIO320 EXAM 1-Fall 2009 Name ______

True/False (1 point each)

__F__ 1. Mature B cells () bind only to processed .

__F__ 2. The intrinsic pathway of programmed death relies on the death receptor called FAS.

__F__ 3. Natural Killer cells proliferate in response to antigen. __F__ 4. In the 21st century, the leading cause of death in the United States is infectious disease.

__T__ 5. MHC Class I molecules are found on all nucleated cell types.

__F__ 6. Mature, fully differentiated T cells are found in the cortex of the .

__F__ 7. B Cells are not subjected to .

__F__ 8. Relatively speaking, the innate is a slow response while the is a very fast response.

__F__ 9. Only immature T lymphocytes are subjected to . __T__10. Antigen is presented to mainly in secondary lymphoid organs.

__T__11. C3 is the most abundant complement component in the body.

__T__12. T cell receptors are composed of constant and variable regions.

__T__13. Mucosal membrane are collectively considered the largest anatomical barrier for the .

__F__14. The innate immune system is not capable of recognizing carbohydrate and lipids on the surface of common pathogens.

__T__15. Peripheral tolerance is an important mechanism to prevent .

__T__16. cells are considered "professional ."

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1 MICROBIO320 EXAM 1-Fall 2009 Name ______Fill-in List the three (3) different complement pathways. For each, fill in what the complement components are recognizing. For example: general pathogen surface. (6 pts)

Complement Pathway Complement Components Recognize:

17. CLASSICAL PATHWAY 18. ANTIGEN/ COMPLEXES

19. MANNOSE-BINDING LECTIN PATWAY 20. MANNOSE ON PATHOGEN SURFACE

21. ALTERNATIVE PATHWAY 22. GENERAL PATHOGEN SURFACES

For each column, simply answer yes or no for each of the properties listed. (8 pts)

Properties Immunoglobulin T Cell Receptor

Secreted forms 23. YES 24. NO

VDJ recombination 25. YES 26. YES

Transmembrane forms 27. YES 28. YES

For the following table, please fill in either TH1 or TH2. The functions below are related to when the T Cell subtype is activated.

Properties Helper T cell subtype

Releases the IFNγ 31. TH1 Coordinates responses to extracellular pathogens 32. TH2 Releases the cytokine IL4 33. TH2 Macrophage activation 34. TH1

Please list four (4) of the major events of phagocytosis.

Phagocytic Events (I excepted any of the 5 following or something close)

35. CHEMOTAXIS

36. ADHERENCE

37. INGESTION

38. KILLING LASTLY, ELIMINATION /20 2 MICROBIO320 EXAM 1-Fall 2009 Name ______Define the following terms: Please keep to a single sentence (each 1 pt) 39. Surfactant - A wetting agent that lowers the surface tension. A surface-active lipoprotein complex formed by type II alveolar cells.

40. - Programmed cell death, death by suicide that is INDUCED. This process involves a series of biochemical reaction involving caspases.

41. Anergy - Describes the lack of reaction by the body's defense mechanisms to foreign substances, and is a direct induction of peripheral tolerance.

42. - Portion of a marcomolecule to which an antibody binds; the antigenic determinant.

Indicate two reasons why life expectancy has increased since the 1900's. (There were at least 8 possible reasons listed in Lecture 1) 43.

44.

45-46. How does normal flora act as part of the innate immune system? (2pts) Approximately 100 trillion bacteria and other reside in or on the human body. These normal body flora keep potentially harmful opportunistic pathogens in check and also inhibit the colonization of pathogens by: a. producing metabolic products (fatty acids, bacteriocins, etc.) that inhibit the growth of many pathogens; b. b. adhering to target host cells thus covering them and preventing pathogens from colonizing; c. c. depleting nutrients essential for the growth of pathogens; and d. d. nonspecifically stimulating the immune system.

47-50. Briefly describe the concept behind central tolerance of T lymphocytes. (4 pts) Include in your answer positive and negative selection

4 main points to discuss: occurs in the thymus, naïve T cells mature and are subjected to central tolerance, recognition of self vs. non-self. IMPORTANT CONCEPT: Involves recognition of MCH class molecules in conjunction with self antigen. Positive selection – T cell receptor, antigen, MCH class molecule interaction is of a moderate strength, cells are positively selected. Anything to weak will not make it through MCH class restriction. Negative selection occurs when introduced to other cell in medulla, and the T cell receptor, antigen, MCH class molecule interaction is too strong. These cells are negatively selected. /12 3 MICROBIO320 EXAM 1-Fall 2009 Name ______Matching: Match the statement to the best word. Use the master list below. (1 point each) Please note that there may be more than one correct answer that matches to the definition.

_EE__ 51. Fox3p is a specific marker for this kind of cell. __A__ 52. Major antibody found in secretions such as saliva, tears and breast milk. __T__ 53. This cell type always expresses MHC class II and MHC Class I molecules on the surface. __M__ 54. This molecule presents peptides that were processed through the proteasome and transported through TAP to the ER. _SY__ 55. This cell type requires the synthesis of granzymes and perforin for its function. __N__ 56. CD4 binds to this molecule during T cell activation. _AA__ 57. This cell type is specifically involved in antibody production. __F__ 58. This molecule on the antigen presenting cell is required for co-stimulation during a T cell response. __R__ 59. This cell type undergoes maturation in the . _S,Y__ 60. This type of immune cell destroys target cells. P,M,N_ 61. This molecule participates in the adaptive immune response by forming a ternary complex. __C__ 62. Antibody type that sensitizes mast cells and causes degranulation. __E__ 63. Relatively high levels of this antibody often correlates with first recent exposure to an inducing agent. __J__ 64. This molecule binds to B7. __V__ 65. This cell type is found in the bone marrow and is considered pluripotent. __G__ 66. The signal transduction molecule in the T cell receptor complex that sends the activation signal into the cells nucleus. Master List A. IgA Q. B. IgD R. B lymphocyte C. IgE S. Cytotoxic T lymphocyte D. IgG T. E. IgM U. F. B7 V. Hematopoetic stem cell G. CD3 W. Macrophage H. CD4 X Naïve T lymphocyte I. CD8 Y. J. CD28 Z. K. CTLA-4 AA. Plasma cells L. Fox3p BB. Red blood cells

M. MHC Class I CC. TH1 lymphocyte

N. MHC Class II DD. TH2 lymphocyte O. receptor EE. Treg lymphocyte P. T Cell receptor /16 4 MICROBIO320 EXAM 1-Fall 2009 Name ______Multiple choice – Please circle the correct answer. (1 point each) 67. The heavy chain variable region of all classes/subclasses of Ig are encoded by: A. V & C gene segments. B. V & J gene segments. C. V gene segments only. D. V, D, & J gene segments. E. None of the above.

68. Which of the following is not a component of the specific adaptive immune response? A. T cells B. B cells C. Skin D. E. All of the above

69. "Double positive" T lymphocytes are characterized by the following: A. high levels of FAS B. expression of low levels of Bcl-2 C. presence of CD4 and CD8 on the cell surface D. expression of low levels of the T cell receptor E. All of the above

70. The following are components of the membrane attack complex (MAC) except: A. C2 B. C9 C. C5b D. C7 E. C6

71. The development of self-tolerance in the T-cell compartment is important for the prevention of . Which of the following are examples of peripheral tolerance? A. ignorance B. negative selection C. proliferation D. positive selection E. None of the above

72. The following activate(s) the alternative pathway of complement: A. lipopolysaccharides B. some viruses and virus-infected cells C. fungal and yeast cell walls (zymosin) D. many strains of gram-positive bacteria E. all of the above.

73. Which of the following is incorrect concerning MHC class II molecules? A. B cells may express different MHC class II molecules on their surface. B. MHC class II molecules are synthesized in the endoplasmic reticulum of many cell types. C. Genetically different individuals express different MHC class II alleles. D. MHC class II molecules are associated with b2-microglobulin on the cell surface. E. All are correct

5 MICROBIO320 EXAM 1-Fall 2009 Name ______74. The class-specific antigenic determinants () of immunoglobulins are associated with: A. L chains. B. J chains. C. disulfide bonds. D . H chains. E . variable regions.

75. Which statement about antigen epitopes is FALSE? A An epitope may be shared by two different . B A molecule usually contains multiple epitopes. C T cells bind only processed antigen epitopes. D Some epitopes are more immunogenic than others. E. T cell and B cel recognize antigen identically

76. Which of the following components of complement possess the binding site for the Fc portion of ? A. C1s B. C9 C. C1q D. C3 E. None of the above

77. A cell expressing which of the following is referred to as a “single positive cell”? A. TCR but not CD3 B. αβTCR but not γδTCR C. MHC class I but not MHC class II D. CD8 but not CD4 E. None of the above

78. Viral that are formed inside of an infected cell associate with ______and are presented at the surface of the infected cell. A. B. MHC class I molecules C. MHC class II molecules D. Antibody molecules E. None of the above

79. Which of the following is the first step in the specific immune response to antigen? A. Memory cell formation B. Secretion of antibody molecules C. to D. Secretion of cytokines by T helper cell E. All of the above

6 MICROBIO320 EXAM 1-Fall 2009 Name ______81. The primary and secondary antibody responses differ in A. the predominant isotype generated. B. the number of lymphocytes responding to antigen. C. the speed at which antibodies appear in the serum. D. the biologic functions manifested by the Ig isotypes produced. E. All of the above.

82. Which type of T cell produce cytokines that stimulate B cell differentiation and lead to antibody production? A. Cytotoxic T cells. B. TH1 cells. C. TH2 cells. D. NK T cells. E. Naïve T cells.

83. Which of the following DOES NOT apply to "innate" immune mechanisms? A. absence of specificity. B. activation by a stimulus. C. involvement of multiple cell types. D. a memory component. E. None of the above.

84. The antigen specificity of a particular B cell A. is induced by interaction with antigen. B. is determined only by the L-chain sequence. C. is determined by H + L chain variable region sequences. D. changes after isotype switching. E. All of the above.

85. Which of the following statements concerning T-cell development is correct? A. Progenitor T cells that enter the thymus from the bone marrow have already rearranged their T cell receptor genes. B. Interaction with thymic non-lymphoid cells is critical. C. Maturation in the thymus requires the presence of foreign antigen. D. MHC class II molecules are not involved in positive selection E. None of the above.

86. CD8 A. binds directly to peptide antigen. B. binds to an variable portion of MHC class II molecules. C. binds to an constant portion of MHC class I molecules. D. binds to CD4 on the T cell surface. E. All of the above.

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7 MICROBIO320 EXAM 1-Fall 2009 Name ______87-90. Draw the structure of a B cell Receptor with the proper orientation in a cell membrane. Label the following structures: (4 pts)

Light Chain - LC V V Heavy Chain - HC Hinge region - H Constant region - C LC LC Variable region - V H Igα Igβ C C Cell surface Outside cell

Inside cell Igβ HC HC Igα

91. Which portion of the receptor is involved in signaling after B cell receptor clustering?

____Igα and Igβ ______

92. Why is important? What portion of the receptor undergoes this change? Variable region undergoes hypermutation. SHM diversifies the receptors used by the immune system to recognize foreign antigens and allows the immune system to adapt its response to new threats during the lifetime of an organism. Somatic hypermutation involves a programmed process of affecting the variable regions of immunoglobulin genes. SHM affects only individual immune cells, and the are not transmitted to offspring.

ESSAY QUESTIONS – (Each is 8 points). Pick 1 of the 2 essay questions to answer. Use the lined paper, and please write legibly. If I cannot read your writing you will receive no points for your answer. Indicate at the beginning of your answer which question you have chosen by labeling it with the letter. Remember avoid bullet points. Organize your thoughts and then wirite in complete sentences.

A. Compare and contrast the Endogenous and Exogenous processing pathways for antigen presentation. Discuss 3 points of similarity and 3 points of difference. Use of a diagram may help you frame your discussion.

B. As a member of a research team studying a tribe found in a remote region of New Guinea, you make the astonishing discovery that they have only two V genes for the L chain and only three V genes for the H chain of immunoglobulins. Nevertheless, the tribe members seem healthy and able to resist the diversity of pathogenic organisms endemic to their specific area. Suggest how this might be accomplished, for example how else might diversity be generated?

8 MICROBIO320 EXAM 1-Fall 2009 Name ______

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