Immunity

A patient complaining of watery, itchy eyes and sneezing after being given a flower bouquet as a birthday gift should first be treated with A) a vaccine. B) complement. C) sterile pollen. D) antihistamines. E) monoclonal antibodies.

D) antihistamines.

Which of the following cells are involved in cell-mediated immunity and also respond to class I MHC molecule-antigen complexes? A) cytotoxic T cells B) natural killer cells C) helper T cells D) macrophages E) B cells

A) cytotoxic T cells

The cell-mediated immunity that destroys virally infected cells involves A) cytotoxic T cells. B) natural killer cells. C) helper T cells. D) macrophages. E) B cells.

A) cytotoxic T cells.

The MHC is important in a T cell's ability to A) distinguish self from nonself. B) recognize specific parasitic pathogens. C) identify specific bacterial pathogens. D) identify specific viruses. E) recognize differences among types of cancer.

A) distinguish self from nonself.

The lymphatic fluid A) is a filtrate of the blood, as is urine. B) is completely separate from the circulatory system for blood. C) carries both red and white blood cells. D) functions in adaptive immunity but not in innate immunity. E) carries a toxic gas that kills cancerous cells.

A) is a filtrate of the blood, as is urine.

Innate immunity A) is activated immediately upon infection. B) depends on a newly infected animal's previous exposure to the same pathogen. C) is based on recognition of antigens that are specific to different pathogens. D) is found only in vertebrate animals. E) utilizes highly specific antigen receptors on B cells.

A) is activated immediately upon infection.

Secondary immune responses upon a second exposure to a pathogen are due to the activation of A) memory cells. B) macrophages. C) stem cells. D) B cells. E) T cells.

A) memory cells.

An example of a pathogen that undergoes rapid changes resulting in antigenic variation is A) the influenza virus, which expresses alternative envelope proteins. B) the strep bacteria, which can be communicated from patient to patient with high efficiency. C) human papilloma virus, which can remain latent for several years. D) the causative agent of the autoimmune disease known as rheumatoid arthritis. E) multiple sclerosis, which attacks the myelinated cells of the nervous system.

A) the influenza virus, which expresses alternative envelope proteins.

For the successful development of a vaccine to be used against a pathogen, it is necessary that A) the surface antigens of the pathogen not change. B) a rearrangement of the B cell receptor antibodies takes place. C) all of the surface antigens on the pathogen be identified. D) the pathogen has only one epitope. E) the MHC molecules are heterozygous.

A) the surface antigens of the pathogen not change.

The activation of helper T cells is likely A) when an antigen is displayed by a dendritic cell. B) when a cytotoxic T cell releases cytokines. C) when natural killer (NK) cells come in contact with a tumor cell. D) in the bone marrow during the self-tolerance test. E) when B cells respond to T -independent antigens.

A) when an antigen is displayed by a dendritic cell.

The receptors on T cells and B cells bind to A) antibodies. B) antigens. C) natural killer cells. D) double-stranded RNA. E) immunoglobulins.

B) antigens.

Select the pathway that would lead to the activation of cytotoxic T cells. A) B cell contact antigen --> helper T cell is activated --> clonal selection occurs B) body cell becomes infected with a virus --> new viral proteins appear --> class I MHC molecule-antigen complex displayed on cell surface C) self-tolerance of immune cells --> B cells contact antigen --> cytokines released D) complement is secreted --> B cell contacts antigen --> helper T cell activated --> cytokines released E) cytotoxic T cells --> class II MHC molecule-antigen complex displayed --> cytokines released --> cell lysis

B) body cell becomes infected with a virus --> new viral proteins appear --> class I MHC molecule-antigen complex displayed on cell surface

T cells of the immune system include A) CD4, CD8, and plasma cells. B) cytotoxic and helper cells. C) plasma, antigen -presenting, and memory cells. D) lymphocytes, macrophages, and dendritic cells. E) class I MHC, class II MHC, and memory cells.

B) cytotoxic and helper cells.

Inflammatory responses typically include A) clotting proteins migrating away from the site of infection. B) increased activity of phagocytes in an inflamed area. C) reduced permeability of blood vessels to conserve plasma. D) release of substances to decrease the blood supply to an inflamed area. E) inhibiting the release of white blood cells from bone marrow.

B) increased activity of phagocytes in an inflamed area.

Vaccination increases the number of A) different receptors that recognize a pathogen. B) lymphocytes with receptors that can bind to the pathogen. C) epitopes that the immune system can recognize. D) macrophages specific for a pathogen. E) MHC molecules that can present an antigen.

B) lymphocytes with receptors that can bind to the pathogen.

The cells involved in innate immunity, whose absence increases the chances of developing malignant tumors, are A) cytotoxic T cells. B) natural killer cells. C) helper T cells. D) macrophages. E) B cells.

B) natural killer cells.

Adaptive immunity depends on A) traits common to groups of pathogens. B) pathogen-specific recognition. C) maternal provision of antibodies to offspring. D) plants being exposed to new pathogens. E) having exhausted all options for innate immunity responses.

B) pathogen-specific recognition.

A key part of the humoral immune response is A) the attack of cytotoxic T cells on infected host cells. B) the production of antibodies by plasma cells. C) perforation of infected host cells by perforin. D) the attack of phagocytes on living pathogens. E) the initiation of programmed cell death in infected host cells.

B) the production of antibodies by plasma cells.

Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells? A) B cells confer active immunity; cytotoxic T cells confer passive immunity. B) B cells kill pathogens directly; cytotoxic T cells kill host cells. C) B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells. D) B cells carry out the cell-mediated response; cytotoxic T cells carry out the humoral response. E) B cells respond the first time a pathogen is present; cytotoxic T cells respond subsequent times.

C) B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

Clonal selection is an explanation for how A) a single type of stem cell can produce both red blood cells and white blood cells. B) V, J, and C gene segments are rearranged. C) an antigen can provoke production of high levels of specific antibodies. D) HIV can disrupt the immune system. E) macrophages can recognize specific T cells and B cells.

C) an antigen can provoke production of high levels of specific antibodies.

In the human disease known as lupus, there is an immune reaction against a patient's own DNA from broken or dying cells, which categorizes lupus as A) an allergy. B) an immunodeficiency. C) an autoimmune disease. D) an antigenic variation. E) a cancer.

C) an autoimmune disease.

An inflammation-causing signal released by mast cells at the site of an infection is A) an interferon. B) lymphatic fluid. C) histamine. D) mucus. E) sodium ions.

C) histamine.

Naturally acquired passive immunity results from the A) injection of vaccine. B) ingestion of interferon. C) placental transfer of antibodies. D) absorption of pathogens through mucous membranes. E) injection of antibodies.

C) placental transfer of antibodies.

Which of the following would not help a virus avoid triggering an adaptive immune response? A) having frequent mutations in genes for surface proteins B) infecting cells that produce very few MHC molecules C) producing proteins very similar to those of other viruses D) infecting and killing helper T cells E) building the viral shell from host proteins

C) producing proteins very similar to those of other viruses

A systemic inflammatory response that is often life-threatening is A) mild fever. B) aches and dull pain. C) septic shock. D) high blood pressure. E) increased white blood cell count.

C) septic shock.

A newborn who is accidentally given a drug that destroys the thymus would most likely A) lack class I MHC molecules on cell surfaces. B) lack humoral immunity. C) be unable to genetically rearrange antigen receptors. D) be unable to differentiate and mature T cells. E) have a reduced number of B cells and be unable to form antibodies.

D) be unable to differentiate and mature T cells.

B cells have antigen receptors that bind to antigens that are either freely dissolved or present on the surface of invading/foreign cells. T cells have antigen receptors that A) are active only in lymph nodes. B) bind only to antigens present on the surface of the invading/foreign cells. C) bind only to freely dissolved antigens in the plasma. D) bind to antigens presented on major histocompatability complexes by host cells. E) bind to antigens that are either freely dissolved or present on the surface of invading/foreign cells.

D) bind to antigens presented on major histocompatability complexes by host cells.

Antigens are A) proteins found in the blood that cause foreign blood cells to clump. B) proteins embedded in B cell membranes. C) proteins that consist of two light and two heavy polypeptide chains. D) foreign molecules that trigger the generation of antibodies. E) proteins released during an inflammatory response.

D) foreign molecules that trigger the generation of antibodies.

Engulfing-phagocytic cells of innate immunity include all of the following except A) neutrophils. B) macrophages. C) dendritic cells. D) natural killer cells.

D) natural killer cells.

Yearly vaccination of humans for influenza viruses is necessary because A) of an increase in immunodeficiency diseases. B) flu can generate anaphylactic shock. C) surviving the flu one year exhausts the immune system to nonresponsiveness the second year. D) rapid mutation in flu viruses alters the surface proteins in infected host cells. E) flu leads to autoimmune disorders.

D) rapid mutation in flu viruses alters the surface proteins in infected host cells.

An epitope is A) part of the interferons that penetrate foreign cells. B) a protein protruding from the surface of B cells. C) two structurally similar antibodies dissolved in the blood plasma. D) that part of an antigen that actually binds to an antigen receptor. E) a mirror image of an antigen.

D) that part of an antigen that actually binds to an antigen receptor.

Immunological memory accounts for A) the human body's ability to distinguish self from nonself. B) the observation that some strains of the pathogen that causes dengue fever cause worse disease than others. C) the ability of a helper T cell to signal B cells via cytokines. D) the ancient observation that someone who had recovered from the plague could safely care for those newly diseased. E) the ability of the immune system to present antigen fragments in association with MHC antigens.

D) the ancient observation that someone who had recovered from the plague could safely care for those newly diseased.

Phagocytosis of microbes by macrophages is enhanced by A) the binding of antibodies to the surface of microbes. B) antibody-mediated agglutination of microbes. C) the release of cytokines by activated B cells. D) the binding of antibodies to the surface of microbes and antibody -mediated agglutination of microbes only. E) the binding of antibodies to the surface of microbes, antibody -mediated agglutination of microbes, and the release of cytokines by activated B cells.

D) the binding of antibodies to the surface of microbes and antibody -mediated agglutination of microbes only.

The cells and signaling molecules that initiate inflammatory responses are A) the phagocytes and the lysozymes. B) the phagocytes and the chemokines. C) the dendritic cells and the interferons. D) the mast cells and the histamines. E) the lymphocytes and the interferons.

D) the mast cells and the histamines.

In active immunity, but not passive immunity, there is A) acquisition and activation of antibodies. B) proliferation of lymphocytes in bone marrow. C) the transfer of antibodies from the mother across the placenta. D) the requirement for direct exposure to a living or simulated pathogen. E) the requirement of secretion of interleukins from macrophages.

D) the requirement for direct exposure to a living or simulated pathogen.

A cell type that interacts with both the humoral and cell -mediated immune pathways is a A) plasma cell. B) cytotoxic T cell. C) natural killer cell. D) CD8 cell. E) helper T cell.

E) helper T cell.

The eyes and the respiratory tract are both protected against infections by A) the mucous membranes that cover their surface. B) the secretion of complement proteins. C) the release of slightly alkaline secretions. D) the secretion of lysozyme onto their surfaces. E) interferons produced by immune cells.

D) the secretion of lysozyme onto their surfaces.

Jenner's successful use of cowpox virus as a vaccine against the smallpox virus is due to the fact that A) the immune system responds nonspecifically to antigens. B) the cowpox virus made antibodies in response to the presence of smallpox. C) cowpox and smallpox are antibodies with similar immunizing properties. D) there are some antigenic determinants common to both pox viruses. E) cowpox and smallpox are caused by the same virus.

D) there are some antigenic determinants common to both pox viruses.

The primary function of humoral immunity is A) to defend against fungi and protozoa. B) to reject transplanted tissues. C) to protect the body against cells that become cancerous. D) to protect the body against extracellular pathogens. E) to defend against bacteria and viruses that have already infected cells.

D) to protect the body against extracellular pathogens.

Arrange these components of the mammalian immune system as it first responds to a pathogen in the correct sequence. I. Pathogen is destroyed. II. Lymphocytes secrete antibodies. III. Antigenic determinants from pathogen bind to antigen receptors on lymphocytes. IV. Lymphocytes specific to antigenic determinants from pathogen become numerous. V. Only memory cells remain. A) I --> III --> II --> IV --> V B) III --> II --> I --> V --> IV C) II --> I --> IV --> III --> V D) IV --> II --> III --> I --> V E) III --> IV --> II --> I --> V

E) III --> IV --> II --> I --> V

Bacteria entering the body through a small cut in the skin A) inactivate the erythrocytes. B) stimulate apoptosis of nearby body cells. C) stimulate release of interferons. D) stimulate natural killer cell activity. E) activate a group of proteins called complement.

E) activate a group of proteins called complement.

A patient who undergoes a high level of mast cell degranulation, dilation of blood vessels (swelling), and acute drop in blood pressure is likely suffering from A) an autoimmune disease. B) a typical allergy that can be treated by antihistamines. C) an organ transplant, such as a skin graft. D) the effect of exhaustion on the immune system. E) anaphylactic shock immediately following exposure to an allergen.

E) anaphylactic shock immediately following exposure to an allergen.

The function of antibodies is to A) inject toxins into living pathogens. B) secrete cytokines that attract macrophages to infection sites. C) release perforins to disrupt infected cells. D) act as Toll-like receptors. E) mark pathogenic cells for destruction.

E) mark pathogenic cells for destruction.

Within a differentiated B cell, the rearrangement of DNA sequences between variable regions and joining regions is accomplished by A) polyadenylase. B) RNA polymerase. C) reverse transcriptase. D) epitopase. E) recombinase.

E) recombinase.

Clonal selection of B cells activated by antigen exposure leads to production of A) large numbers of neutrophils. B) large quantities of the antigen initially recognized. C) vast numbers of B cells with random antigen -recognition receptors. D) long-lived erythrocytes that can later secrete antibodies for the antigen. E) short-lived plasma cells that secrete antibodies for the antigen.

E) short-lived plasma cells that secrete antibodies for the antigen.