Ch. 21 Study Guide

[Ch. 21 Clicker Question #2] Which of the following is NOT classified as part of innate immunity? (a) Antibodies (immunoglobulins) (b) Macrophages (c) Mucous membranes (d) Natural Killer (NK) cells (e) Toll-like receptors (TLRs)

(a) Antibodies (immunoglobulins)

[Ch. 21 Clicker Question #7] Which type of cell killing is NOT a result of antibodies binding to antigens? (a) Apoptosis (b) Complement-induced lysis (c) Phagocytosis

(a) Apoptosis

[Ch. 21 CYU #4] Under what circumstances might NK cells kill our own cells?

Our own cells are killed by NK cells when they have been infected by viruses or when they have become cancerous.

[Ch. 21 Clicker Question #4] The complement cascade includes actions like the following: "C3b cleaves C5 into C5a and C5b." Based on this statement, you can conclude that (a) C3b is an active protease (b) C3b is not active because it does not have the subscript "a" (c) C5a assists with clotting (d) C5a and C5b are active proteases

(a) C3b is an active protease

[Ch. 21 CQ #15] Which of the following statements is characteristic of a secondary humoral response? (a) It occurs much more rapidly than a primary response. (b) It occurs only in the spleen. (c) It results in less memory-cell circulation. (d) It results in less antibody secretion. (e) It triggers fever.

(a) It occurs much more rapidly than a primary response.

[Ch. 21 CQ #10] When a localized area exhibits increased capillary filtration, hyperemia, and swelling, it is an indication that __________. (a) inflammation is occurring (b) antibodies are phagocytizing target cells (c) fever is developing (d) antigens are present (e) an immune response is underway

(a) inflammation is occurring Inflammation usually occurs when histamine or complement is mobilized.

[Ch. 21 PT #1] Which of the following types of cells is involved in adaptive immunity? (a) natural killer cells (b) B cells (c) neutrophils (d) macrophages

(b) B cells T cells and B cells are lymphocytes that are involved in the adaptive (also called specific) immune response. Macrophages, neutrophils, and natural killer cells (NK cells) are innate immune responders.

[Ch. 21 RQ #6] Lymphocytes that develop immunocompetence in the bone marrow are (a) T lymphocytes (b) B lymphocytes (c) NK cells (d) B and T lymphocytes

(b) B lymphocytes

[Ch. 21 CQ #1] A nonself substance that can provoke an immune response is called a(n) __________. (a) immunoglobulin (b) antigen (c) antibody (d) colony-stimulating factor (e) interferon

(b) antigen An antigen is a nonself substance that can mobilize the adaptive defenses and provoke an immune response.

[Ch. 21 Clicker Question #6] The general process of clonal selection applies to (a) cells only (b) cells only (c) Both B cells and T cells (d) Neither B cells nor T cells

(c) Both B cells and T cells

[Ch. 21 RQ #1] All of the following are considered innate body defenses except (a) complement (b) phagocytosis (c) antibodies (d) lysozyme (e) inflammation

(c) antibodies

[Ch. 21 PT #10] Self-reactive B cells are eliminated in the __________. (a) lymph nodes (b) thymus (c) bone marrow (d) spleen

(c) bone marrow T cells are screened for self-tolerance in the thymus. B cells mature in the bone marrow. Self-reactive B cells are eliminated in the bone marrow.

[Ch. 21 RQ #7] Cells that can directly attack target cells include all of the following except (a) macrophages (b) cytotoxic T cells (c) helper T cells (d) natural killer cells

(c) helper T cells

[Ch. 21 CQ #12] Which cells stimulate both arms of the immune response? (a) complement cells (b) killer T cells (c) helper T cells (d) basophils (e) plasma cells

(c) helper T cells Without helper T cells, there is no immune response.

[Ch. 21 PT #17] Which of the following are MISMATCHED? (a) B cells: can be activated to produce antibodies (b) regulatory T cells: release inhibitory cytokines to dampen the immune response (c) helper T cells: directly target and kill cancer cells (d) cytotoxic T cells: carry out cellular immune responses

(c) helper T cells: directly target and kill cancer cells T helper cells are lymphocytes that organize the cellular and humoral immune response branches of the immune system. They do not directly target or attack anything; rather, they organize the immune defenses. B cells carry out the humoral response. Upon activation, B cells become plasma cells that will produce antibodies. Cytotoxic T cells carry out cellular immune responses. They target and kill virus-infected cells as well as cancer cells. Regulatory T cells are able to release inhibitory cytokines to dampen the immune response once the foreign antigen has been cleared from the body.

[Ch. 21 PT #8] __________ are substances that can trigger the adaptive defenses and provoke an immune response. (a) Antibodies (b) Interleukins (c) Haptens (d) Antigens

(d) Antigens Antigens are substances that can induce an adaptive immune defense and provoke an immune response. Antibodies can be made in response to foreign antigens. Haptens are not immunogenic unless they combine with other substances in the body; they are not able to independently provoke an immune response.

[Ch. 21 CQ #30] Which of the following is NOT a mechanism of antibody action? (a) precipitation (b) agglutination (c) neutralization (d) B cell synthesis

(d) B cell synthesis Defensive mechanisms used by antibodies include neutralization, agglutination, precipitation, and complement fixation.

[Ch. 21 Specific Question #8] "B cell" and "T cell" are both nicknames for types of (a) Antibodies (b) Erythrocytes (c) Helper cells (d) Lymphocytes (e) Macrophages

(d) Lymphocytes.

[Ch. 21 Specific Question #3] The cell type that best accounts for why a pathogen's 2nd infection will be less severe than the first is (a) Cytotoxic T cells (b) Helper T cells (c) Macrophages (d) Memory B cells and Memory T cells (e) Plasma cells

(d) Memory B cells and Memory T cells

[Ch. 21 PT #9] __________ is the property of lymphocytes that prevents them from attacking the body's own cells. (a) Immunocompetence (b) Antigenicity (c) Immunological memory (d) Self-tolerance

(d) Self-tolerance T cells are screened for self-tolerance in the thymus. B cells mature and are screened for self-tolerance in the bone marrow. Self-tolerance is what prevents lymphocytes from attacking the body's own cells. Without self-tolerance, a person develops autoimmune disorders.

[Ch. 21 CQ #5] Lymphocytes that develop immunocompetence in the thymus are __________. (a) B lymphocytes (b) macrophages (c) NK cells (d) T lymphocytes

(d) T lymphocytes T cells get their name from the fact that they develop in the thymus.

[Ch. 21 RQ #3] Antibodies released by plasma cells are involved in (a) humoral immmunity (b) immediate hypersensitivity reactions (c) autoimmune disorders (d) all of the above

(d) all of the above

[Ch. 21 PT #7] Humoral immunity is provided by __________. (a) complement proteins (b) T cells (c) interferons (d) antibodies

(d) antibodies Adaptive immunity is categorized as being either cellular or humoral. Humoral immunity is facilitated by antibodies, which are made by plasma cells (activated B cells). The chief orchestrators of cellular immunity are T cells.

[Ch. 21 Clicker Question #5] HIV, the AIDS virus, infects and kills helper T cells. This leads to major deficits in (a) innate immunity only (b) both innate and acquired immunity (c) cellular acquired immunity only (d) both cellular and humoral acquired immunity

(d) both cellular and humoral acquired immunity

[Ch. 21 RQ #11] The cell type most often invaded by HIV is a(n) (a) eosinophil (b) cytotoxic T cell (c) natural killer cell (d) helper T cell (e) B cell

(d) helper T cell

[Ch. 21 CQ #9] Which type of disease results from the inability of the immune system to distinguish self- from nonself-antigens? (a) SCID (b) anaphylaxis (c) immunodeficiency (d) allergy (e) autoimmune disease

(e) autoimmune disease Multiple sclerosis and lupus are good examples of autoimmune disease, in which the body attacks its own cells.

[Ch. 21 Clicker Question #8] Which aspect(s) of immune defense apply more to viruses than to bacteria? (a) complement (b) cytotoxic T cells (c) NK cells (d) plasma cells (e) both B and C

(e) both B and C

[Ch. 21 CQ #3] Complement proteins work by __________. (a) phagocytosis of target cells (b) neutralization of antigens (c) producing antibodies (d) creating an impermeable barrier (e) forming pores in the membranes of target cells

(e) forming pores in the membranes of target cells Complement usually works with antibodies in the classical pathway to open pores in the target cell membrane.

[Ch. 21 CQ #6] Saliva and lacrimal fluids contain which enzyme that destroys bacteria? (a) amylase (b) reverse transcriptase (c) trypsin (d) pepsin (e) lysozyme

(e) lysozyme Lysozyme lyses the cell wall and membrane of bacteria.

[Ch. 21 CQ #7] Which immune cell is able to respond quickly after any subsequent encounter with the same antigen? (a) helper T cell (b) plasma cell (c) basophil (d) antigen-presenting cell (e) memory cell

(e) memory cell Memory cells can circulate for years and respond quickly after any subsequent encounter with the same antigen.

[Ch. 21 RQ #17] Differentiate between a primary and a secondary immune response. Which is more rapid and why?

A primary immune response results in cellular proliferation, differentiation of mature effector and memory lymphocytes, and the synthesis and release of antibodies—a series of events that takes 3 to 6 days. The secondary immune response results in huge numbers of antibodies flooding into the bloodstream within hours after recognition of the antigen, as well as an amplified cellular attack. Secondary responses are faster because the immune system has been primed to the antigen and sizable numbers of sensitized memory cells are already in place. (p. 797)

[Ch. 21 CYU #16] List four ways in which antibodies can bring about destruction of a pathogen.

Antibodies can bring about destruction of pathogen via "PLAN"--phagocytosis, lysis (via complement), agglutination, or neutralization.

[Ch. 21 RQ #19] How do antibodies help defend the body?

Antibodies help defend the body by activation of complement proteins, neutralization, which binds antigens and removes them from the circulating population, agglutination, which clumps antigens into groups easily removed by phagocytes, etc., and precipitation, which causes antigens to settle out of the plasma. Complement fixation and neutralization are most important in body protection. (pp. 800-801)

[Ch. 21 Specific Question #7] Cells like B cells, dendritic cells, and macrophages all are capable of "antigen presentation." Briefly describe what antigenpresentationis and how helper T cells and cytotoxic T cells respond to it.

Antigen presentation is when "antigen-presenting" cells, like dendritic cells or macrophages or B cells, ingest a protein antigen and chop it into pieces and then display some of these pieces on the cell surface, held by MHC proteins. Both helper T cells and cytotoxic T cells are "selected" by interacting (via their own protein receptors) with these antigen-presenting cells; both divide to form more cells.

[Ch. 21 RQ #25] Although the adaptive immune syste, has two arms, it has been said, "no T cells, no immunity." Explain.

Cytokines released by helper T cells help to amplify and regulate both the humoral and cellular immune responses as well as the innate defense responses. In the absence of these T cells, both B and T lymphocytes would respond inadequately to antigens. (p. 805)

[Ch. 21 RQ #24] Differentiate between humoral and cellular adaptive immunity.

Humoral immunity is provided by the antibodies in the body's fluids. Cellular immunity is provided by non-antibody-producing lymphocytes; that is, T cells. (pp. 796, 801)

[Ch. 21 Specific Question #2] What is clonal selection? Explain why this process is both "clonal" and a "selection."

In general, clonal selection is the process by which only cells with protein receptors that recognize antigens from a specific pathogen that is currently threatening the body are "selected" to reproduce via cell division. This selection is "clonal" in the sense that all of the daughter cells produced are clones of the selected cells.

[Ch. 21 Specific Question #4] Summarize the ways in which secreted antibodies help protect us. What 2 types of killing may result?

P-L-A-N: Precipitation, Lysis (from complement), Agglutination, and Neutralization. Agglutination can lead to phagocytosis, another form of killing in addition to lysis.

[Ch. 21 CYU #19] What is the function of the abundant endoplastic reticulum in plasma cells? What other organelle(s) would be especially abundant in plasma cells? Why?

Plasma celsl make large amounts of antibodies--proteins that are exported from the cell. Rough ER is the site where proteins that are exported are synthesized. Ribosomes, the Golgi apparatus, and secretory, and secretory vesicles are also required for protein synthesis and export, and so would also be abundant in these cells.

[Ch. 21 Specific Question #5] How do both the humoral and cellular immune responses help combat a viral infection?

The humoral response helps combat viruses in their extracellular stage; antibodies (produced by B cells) can bind to them and help neutralize them, as noted in the previous message. The cellular response helps kill infected cells; in particular, cytotoxic T cells bind to infected cells and deliver apoptosis-promoting proteins to them.

[Ch. 21 CYU #1] What distinguishes the innate defense system from the adaptive defense system?

The innate defense system is always ready to respond immediately, whereas it takes considerable time to mount the adaptive defense system. The innate defenses consist of surface barriers and internal defenses, whereas the adaptive defenses consist of humoral and cellular immunity, which rely on B and T lymphocytes.

[Ch. 21 CYU #14] Why is the secondary response to an antigen so much faster than the primary response?

The secondary response to an antigen is faster than the primary response because the immune system has already been "primed" and has memory cells that are specific for that particular antigen.

[Ch. 21 Specific Question #6] Are the humoral and cellular adaptive immune responses completely separate from each other, or do they overlap? Explain.

They do overlap. T helper cells are involved in both; in humoral immunity, they interact with antigen-presenting B cells and stimulate some to become antibody-secreting plasma cells, while in cellular immunity, they interact with antigen-presenting cells and give a boost to cytotoxic T cells

[Ch. 21 Specific Question #1] How are toll-like receptors different than antibodies?

Toll-like receptors/Antibodies: Part of innate immunity; Part of adaptive immunity. Surface of cells like macrophages, dendritic cells; made by B cells. Bind to common features of broad categories of pathogens; bind to unique pathogen antigens. 11 or so types; thousands of types.

[Ch. 21 Specific Question #9] Cells that can directly attack target cells include all of the following except (a) Macrophages (b) Cytotoxic T cells (c) Helper T cells (d) Natural killer (NK) cells

c) Helper T cells.

[Ch. 21 Clicker Question #3] Chemical communication between cells of the immune system is best considered (a) Endocrine (b) Neuroendocrine (c) Paracrine (d) Synaptic

c) Paracrine