Ch 21: Immune System Flashcards

1) Virus infected cells secrete interferons to "warn" other cells of the presence of virus and deny entry to them.

2) Cytotoxic T cells and NK cells kill by secretion of proteins. The first called perforin which forms complexes that penetrate the cell membrane and allows the passage of the apoptosis inducing protein granzyme to enter the targeted cell.

3) Dendritic cells and macrophages kill by ingestion and destruction of particulate matter in a process called phagocytosis.

4) The respiratory burst produced by activated macrophages releases free radicals which are effective at killing pathogens.

5) The directional movement of cells in response to chemicals is called chemotaxis.

6) Soluble proteins secreted by plasma cells are called antibodies.

7) Viral infection will provoke cell mediated immunity but will not activate a humoral response.

8) Fever is often a beneficial immune response because it can speed the activities of leucocytes.

9) Monoclonal antibodies are used in clinical laboratory diagnosis because they bind to many antigenic determinates.

10) B cells must accomplish double recognition: They must simultaneously recognize self and nonself to be activated.

11) Some immunocompetent cells will never encounter an antigen to which they can bind and therefore will never be called to service in our lifetime.

12) Anaphylactic shock is a rare but severe allergic response that may occur if the allergen enters the blood stream.

13) In a case of immediate hypersensitivity the immune system responds with an allergic response on the first exposure to the allergen.

14) Subacute hypersensitivities are categorically less harmful than acute (immediate) hypersensitivities.

15) The nucleotide sequence within the genes that produce B cell receptor and antibodies are reshuffled by a process called somatic recombination. This produces the huge variability in antibody types.

16) Antibodies typically act extracellularly in body fluids and are therefore considered part of the humoral branch of adaptive immunity.

1) An advantage to adaptive immunity is ________. A) the use of antibodies that cause cell lysis and kill invading cells B) the ability of its individual cells to respond to many different pathogens C) its memory cells that provide quicker, larger and more efficient immune response upon second exposure to an antigen D) its need for several cells to be activated over several days on first exposure

2) An advantage of innate immunity is ________. A) its barriers that prevent pathogens from entering into the body B) the use of antibodies to cause cell lysis and kill invading cells C) the numerous steps in the activation of its cells that can prevent autoimmune disease D) the specificity of its individual cells which specialize in the removal on one type of antigen

3) B-lymphocytes are categorized as part of the adaptive branch of the immune system for all of the following reason but one. Which of the following is not one of the reasons B-lymphocytes are considered part of the adaptive immunity? A) Their receptors will bind to only one antigen. B) They are a first line of defense that can begin killing pathogens immediately. C) They require costimulation from an activated T-helper cell. D) They produce memory cells when activated.

4) Overlap in the innate and adaptive immune system is seen in all of the following examples but one. Which of the following examples does not illustrate the overlap of innate and adaptive immune responses? A) Dendritic cells presenting antigens on their MHC II proteins to T-helper cells. B) Plasma cells that produce large amounts of IgE that will ultimately allow mast cells to release histamine. C) NK cells causing apoptosis of an abnormal host cell, lacking MHC proteins. D) Macrophages becoming activated macrophages in response to cytokines released by T-helper cells.

5) Which of the following examples below describes an autoimmune disease? A) Release of bacterial endotoxins that block acetylcholine release result in muscle paralysis. B) Antibody binding to acetylcholine receptors of the motor end plate resulting in muscle weakness. C) Infection and death of T-helper cells by a virus, resulting in a loss of adaptive immunity. D) Uncontrolled cell division resulting in cell surface abnormalities recognized by NK cells.

6) Which of the following does not describe actions of interferon (IFN)? A) IFN binds to normal, uninfected cells stimulating the activation of genes that produce anti-viral proteins. B) IFN can penetrate the viral capsid and destroy the virus. C) Virally infected cells can release interferon which attracts NK cells to attack and kill the IFN secreting cell. D) IFN will attract macrophages to the secreting cell to be removed by phagocytosis.

7) A vaccine is effective because ________. A) B-lymphocytes are unable to mount an immune response the first time they are exposed to a new pathogen B) the secondary response of the adaptive immunity is faster and more efficient the primary response C) the vaccine contains the lymphocytes necessary to fight infection D) the vaccine contains the antibodies necessary to fight infection

8) A flu vaccine is needed seasonally to be effective but a polio vaccine is only needed once. The best explanation of this is ________. A) the flu vaccine is substantially weaker than the polio vaccine B) exposure to flu vaccine produces no memory cells from proliferating B-lymphocytes C) the polio virus is substantially weaker than the flu virus D) the flu has several strains that change seasonally

9) All of the following are true of the classical pathway of complement activation except one. Select the one answer that does not describe the classical pathway of complement activation. A) It is an example of overlap between innate and adaptive immune function. B) Classical activation will result in enhanced inflammation, opsonization as well as formation of MAC proteins. C) It requires that circulating antibodies are bound to antigens. D) It activates T-helper cells by presenting antigen to them.

10) Vaccines work by ________. A) boosting innate immunity with cytokines B) providing the necessary antibodies to fight infections C) suppressing inflation to help speed healing D) priming the adaptive immunity with a relatively harmless primary exposure

11) Inflammation ________. A) is caused by bacterial activity to enhance the spread of disease B) brings more leukocytes to the sight of infection C) is caused by viral activity to enhance the spread of the disease D) slows the healing process with swelling that can impair bodily function

12) Membrane attack complex (MAC) kills by ________. A) providing a passage for antibodies to enter into the bacterial cytosol B) disrupting the selectively permeability of a bacteria's plasma membrane C) penetrating the capsule of the bacteria giving antibiotic drugs access to bacterial cells D) allowing the organelles to spill free from the bacteria

13) All but one of the following occur during the inflammatory response. Select the example below that does not describe the process of inflammation. A) Vasoconstriction will prevent excessive blood loss due to injury. B) Chemotaxis draws leucocytes to the site of injury. C) Increases capillary permeability. D) Release of prostaglandins resulting in pain.

14) During inflammation fluids will passively diffuse out of blood vessels into the nearby, infected tissues. This implies all of the following except ________. A) B-lymphocytes will differentiate to become plasma cells B) the surrounding tissue will swell with excessive fluids C) the osmolarity of the fluids surrounding infected tissue is higher than the plasma D) nearby capillaries have become more permeable

15) Choose the best description of an antigen. A) part or a piece of a disease or pathogen B) a particle that triggers the adaptive immunity C) a particle (typically a foreign protein) that triggers inflammation D) a chemical that enhances or modifies immune response

16) Which of the following best describes the qualities of most antigens? A) macromolecules that are produced by the host organism B) atomic elements that are not normally present in the human body C) macromolecules that are foreign to the host D) atomic elements that are harmful or toxic

17) Allergens differ from antigens because ________. A) allergens are primarily plant derived while antigens are bacterial or viral in nature B) allergens are only active seasonally and are generally harmless to the body C) allergens do not involve the leucocytes, they simply stimulate the inflammatory response D) allergens produce an abnormally large immune response to what is an otherwise harmless particle

18) Without the positive selection process in lymphocyte maturation ________. A) NK cells would be non-functional B) monocytes would not be able to migrate into infected tissue and differentiate into macrophages C) T-cells would not be able to properly bind to APC's and therefore not be activated by them D) autoimmune diseases would be likely to result

19) Select the best description of the negative selection process of lymphocyte maturation. A) removal of lymphocytes that fail to recognize "self" cells B) teaching a lymphocyte to recognize "self" from foreign antigens C) removal of lymphocytes that react with "self" cells D) allowing the survival of lymphocytes that cannot bind to MHC proteins

20) Plasma cells ________. A) have a great deal of rough endoplasmic reticulum reflecting the fact that they secrete a tremendous amount of protein (antibody) B) are small so that they slip between endothelial cells of capillaries to fight infection in the surrounding tissues C) have a great deal of rough endoplasmic reticulum to dispose of ingested pathogens D) are large so that they can envelope their prey by phagocytosis

21) Which of the following is associated with passive immunity? A) booster shot of vaccine B) exposure to an antigen C) infusion of weakened viruses D) passage of IgG antibodies from a pregnant mother to her fetus

22) Which of the following is not a type of T cell? A) helper B) antigenic C) cytotoxic D) regulatory

23) B lymphocytes develop immunocompetence in the ________. A) bone marrow B) lymph nodes C) thymus D) spleen

24) Which of the following is not a function of the inflammatory response? A) prevents the spread of the injurious agent to nearby tissue B) disposes of cellular debris and pathogens C) replaces injured tissues with connective tissue D) sets the stage for repair processes

25) The redness and heat of an inflamed area are due to a local hyperemia caused by ________. A) phagocyte mobilization B) complement production C) vasoconstriction D) vasodilation

26) In clonal selection of B cells, which substance is responsible for determining which cells will eventually become cloned? A) antigen B) interferon C) complement D) antibody

27) Which of the following statements regarding NK cells is a false or incorrect statement? A) NK cells attack cells that display abnormal or lack MHC antigens. B) NK cells are a type of neutrophil. C) NK cells attack cancer cells and virus-infected body cells. D) NK cells are present in the blood, spleen, lymph nodes, and red bone marrow.

28) Which of the following is not a role of activated complement? A) insertion of MAC and cell lysis B) prevention of immediate hypersensitivity reactions C) enhancement of inflammation D) opsonization

29) Interferons ________. A) are routinely used in nasal sprays for the common cold B) are virus-specific, so that an interferon produced against one virus could not protect cells against another virus C) act by increasing the rate of cell division D) interfere with viral replication within cells

30) Regulatory T cells ________. A) aid B cells in antibody production B) may function in preventing autoimmune reactions C) decrease their activity as antigenic stimulus decreases D) release cytokines that increase the activity of cytotoxic T cells and activated B cells

31) Which of the statements below does not describe antigens? A) Antigens only come from microbes. B) The parts of antigen molecules that initiate immune responses are called epitopes or antigenic determinants. C) Antigens can include proteins, nucleic acids, lipoproteins, glycoproteins, and certain large polysaccharides. D) Antigens exhibit immunogenicity and reactivity.

32) Activated T cells and macrophages release ________ to mobilize immune cells and attract other leukocytes into the area. A) cytokines B) interleukin 2 proteins C) perforins D) interleukin 1 proteins

33) Which of the following is characteristic of complete antigens? A) inhibit production of antibodies B) contain many repeating chemical units C) small molecules D) reactivity with an antibody

34) T-cell activation requires ________. A) antigen binding and antibody production B) antigen binding and co-stimulation C) antigen binding, antibody production, and co-stimulation D) antibody production and co-stimulation

35) Cancer cells and virus-infected body cells can be killed before activation of adaptive immunity by ________. A) B lymphocytes B) T lymphocytes C) pinocytosis D) natural killer cells

36) Complement proteins and antibodies coat a microorganism and provide binding sites, enabling macrophages and neutrophils to phagocytize the organism. This phenomenon is termed ________. A) opsonization B) agglutination C) diapedesis D) chemotaxis

37) Monoclonal antibodies are used for the diagnosis of all of the following except ________. A) pregnancy B) elevated blood glucose C) hepatitis D) rabies

38) Innate immune system defenses include ________. A) T cells B) B cells C) plasma cells D) phagocytosis

39) Which of the following statements is incorrect or false? A) Class I MHC molecules are built into the plasma membranes of all body cells. B) Class II MHC molecules appear only on the surface of antigen-presenting cells, thymic cells, and T cells that have been activated by exposure to antigens. C) Haptens lack immunogenicity unless attached to protein carriers. D) MHC proteins are the cell's identity markers.

40) Phagocyte mobilization involves ________. A) monocytes as the most active phagocyte B) diapedesis, during which cells line up against the capillary wall C) mainly neutrophil and macrophage migration into inflamed areas D) margination, which is the process of white cell movement through the walls of capillaries into injured tissues

41) Fever ________. A) production is regulated by chemicals that reset the body's thermostat to a higher setting B) decreases the metabolic rate of the body to conserve energy C) is a higher-than-normal body temperature that is always dangerous D) causes the liver to release large amounts of iron, which seems to inhibit bacterial replication

42) Immunocompetence ________. A) prevents intercellular communication so that only specific cell types respond to the invader B) occurs in one specific organ of the adaptive immune system C) is the ability of individual cells to recognize a specific antigen by binding to it D) requires exposure to an antigen

43) Select the correct statement about active and passive immunity. A) Active and passive humoral immunity are both mechanisms of adaptive immunity that use antibodies. B) Immunological memory is established by passive immunization. C) The antibodies utilized in active immunity are acquired from another organism. D) A vaccination is an example of the introduction of passive immunity into the body.

44) Cytotoxic T cells ________. A) require the double recognition signal of class I MHC plus class II MHC on the target cell in order to function B) self-destruct once the antigen has been neutralized C) function mainly to stimulate the proliferation of other T cell populations D) can directly attack and kill other cells of the body

45) Helper T cells ________. A) function in the adaptive immune system activation B) often function to decrease the immune response C) bind tightly to target cells and release a lymphotoxin called perforin D) release B7 proteins

46) Select the correct statement about immunodeficiency. A) Severe combined immunodeficiency (SCID) disease is an acquired condition. B) Hodgkin's disease is a hereditary immunodeficiency found in children. C) The most common form of immunodeficiency is graft-versus-host (GVH) disease. D) The causative agent in acquired immune deficiency syndrome (AIDS) is a virus that recognizes CD4 proteins.

47) Natural killer (NK) cells ________. A) can kill cancer cells before the immune system is activated B) are also called cytotoxic T cells C) are cells of the adaptive immune system D) are a type of phagocyte

48) Select the correct statement about antigens. A) "Self-antigens" is another name for incomplete antigens. B) The largest type of antigen is called a hapten. C) One antigen may have many different antigenic determinants and may therefore cause the formation of more than one antibody. D) Only small antigens exhibit reactivity.

49) Clonal selection of B cells ________. A) occurs during fetal development B) cannot occur in the presence of antigens C) results in the formation of plasma cells D) only occurs in the secondary immune response

50) The primary immune response ________. A) has a lag period while B cells proliferate and differentiate into plasma cells B) is another name for immunological memory C) occurs more rapidly and is stronger than the secondary response D) occurs when memory cells are stimulated

51) Which of the following cells has the largest role and most widespread effect on immunity? A) cytotoxic T cell B) B cell C) helper T cell D) APC

52) Which of the following is not a mechanism for the development of autoimmune disorders? A) cross-reaction of antibodies formed against foreign antigens (haptens) bound with self-antigens B) mutation followed by the appearance of membrane proteins not previously present C) exposure of previously "hidden" self-antigens to the adaptive immune system during trauma D) a second exposure to an allergen

53) Which of the following is not a complement activation pathway? A) lectin pathway B) alternative pathway C) lactate pathway D) classical pathway

54) Antibody functions include all of the following except ________. A) targeting foreign cells so that complement proteins can cause cellular lysis B) cross-linking cell-bound antigens on red blood cells when blood types are properly matched C) linking soluble antigens together so that they fall out of solution D) binding and inactivating chemical toxins released by bacteria or other microorganisms

55) Which statement is true about T cells? A) They will develop into cytotoxic T cells if antigen is complexed with class II MHC proteins. B) Once activated, they cannot secrete cytokines. C) Their proliferation is enhanced by interleukins 1 and 2. D) They usually directly recognize antigens, which then activates a subpopulation of killer cells.

56) What is the role of interferon in defense against disease? A) protects cells that have not yet been infected by viruses B) activates the inflammatory process C) activates the complement mechanism D) protects cells that have not yet been infected by bacteria

57) Which of the following statements is a false or incorrect statement? A) The lymphoid organs where lymphocytes become immunocompetent are called primary lymph organs. All other lymphoid organs are referred to as secondary lymphoid organs. B) After becoming immunocompetent, the naive T cells and B cells are exported to the bone marrow where the encounters with antigens occur. C) It is our genes, not antigens, that determine what specific foreign substances our immune system will be able to recognize and resist. D) T cells and B cells become activated when they bind with recognized antigens.

58) Which immunoglobulin class is attached to the external surface of B cells and acts as an antigen receptor of the B cell? A) IgE B) IgD C) IgG D) IgM E) IgA