Patho Module 3: INFLAMMATION AND IMMUNITY
Match each term with its definition. Term: -Virulence -Infectivity -Pathogenicity -Toxigenicity Definition: -An important factor in determining a pathogen's ability to produce disease by production of a soluble toxin -Potency of a pathogen measured in terms of the number of microorganisms or micrograms of toxin required to kill the host -Ability of the pathogen to invade and multiply in the host -Pathogenicity is the ability of an agent to produce disease
Virulence=Potency of a pathogen measured in terms of the number of microorganisms or micrograms of toxin required to kill the host Infectivity=Ability of the pathogen to invade and multiply in the host Pathogenicity=Pathogenicity is the ability of an agent to produce disease Toxigenicity=An important factor in determining a pathogen's ability to produce disease by production of a soluble toxin
Match the microorganism with its characteristics. Answers may be used more than once. Characteristics: -A fungal infection such as ringworm -Staining makes microscopic observation possible -Produces a "self" coat by binding to the antigens -Survives by hiding within cells to avoid triggering an immune response Microorganisms: -Mycoses -Viruses -Fungi -Bacteria
A fungal infection such as ringworm=Mycoses Staining makes microscopic observation possible=Fungi Produces a "self" coat by binding to the antigens=Bacteria Survives by hiding within cells to avoid triggering an immune response=Viruses Infection with a fungus is called mycosis and include dermatophytes (e.g., tineas, which refers to several skin mycoses including ringworm, athlete's foot, and others) or yeasts (e.g., Candida, Aspergillus, Cryptococcus).Fungi are diagnosed by microscopic observation of specimens treated with potassium hydroxide and stained to enhance visualization of spheres and filaments.As obligative intracellular pathogens, viruses hide within cells and away from normal inflammatory or immune responses.Some bacterial surface proteins (protein A of Staphylococcus aureus, protein G of Streptococcus pyogenes) bind the Fc portion of the individual's antibody, thus forming a protective coat of "self" protein
Which type of immunity is produced by an individual after either natural exposure to the antigen or after immunization against the antigen? A. Active acquired B. Active innate C. Passive acquired D. Passive innate
A. Active acquired Active acquired immunity (active immunity) is produced by an individual after natural exposure to an antigen or after immunization, whereas passive acquired immunity (passive immunity) does not involve the host's immune response at all.
For which microorganisms is the skin the site of reproduction? A. Bacteria and fungi B. Protozoa and rickettsiae C. Viruses D. Mycoplasma
A. Bacteria and fungi
During an IgE-mediated hypersensitivity reaction, which leukocyte is activated? A. Eosinophils B. Monocytes C. Neutrophils D. T lymphocytes
A. Eosinophils Another important activity of histamine is enhancement of the chemotactic activity of other factors, such as eosinophil chemotactic factor of anaphylaxis (ECF-A), which attracts eosinophils into sites of allergic inflammatory reactions and prevents them from migrating out of the inflammatory site.
Common hay fever allergy is expressed through a reaction that is mediated by: A. IgE B. T cells. C. IgG. D. IgM.
A. IgE Type I reactions are mediated by antigen-specific IgE and the products of tissue mast cells. Most common allergies (e.g., pollen allergies) are type I reactions. In addition, most type I reactions occur against environmental antigens and are therefore allergic.
What is the role of reverse transcriptase in HIV infection? A. It converts RNA into double-stranded DNA. B. It is needed to produce integrase. C. It converts single DNA into double-stranded DNA. D. It transports the RNA into the cell nucleus.
A. It converts RNA into double-stranded DNA. One particular family of viruses, retroviruses (e.g., HIV) carries an enzyme reverse transcriptase that creates a double-stranded DNA version of the virus.
What are the inflammatory effects of nitric oxide (NO)? A. It decreases mast cell function and decreases platelet aggregation. B. It increases neutrophil chemotaxis and platelet aggregation. C. It increases capillary permeability and causes pain. D. It causes smooth muscle contraction and fever.
A. It decreases mast cell function and decreases platelet aggregation. Effects of NO on inflammation include vasodilation by inducing relaxation of vascular smooth muscle, a response that is local and short-lived, and suppression of mast cell function as well as platelet adhesion and aggregation
In Graves disease (hyperthyroidism), autoantibodies bind to and activate receptors for thyroid-stimulating hormone (TSH) so that excessive T4 (thyroxine) is secreted, causing clinical manifestations of an increased metabolism. This mechanism is an example of which type II hypersensitivity reaction? A. Modulation B. Complement-mediated lysis C. ADCC D. Neutrophil-mediated damage
A. Modulation The antibody reacts with the receptors on the target cell surface and modulates the function of the receptor by preventing interactions with their normal ligands, replacing the ligand and inappropriately stimulating the receptor, or destroying the receptor. For example, in the hyperthyroidism (excessive thyroid activity) of Graves disease, autoantibody binds to and activates receptors for TSH (a pituitary hormone that controls the production of the hormone thyroxine by the thyroid).
Which chemical mediator derived from mast cells retracts endothelial cells to increase vascular permeability and causes leukocyte adhesion to endothelial cells? A. Platelet-activating factor (PAF) B. Prostaglandin E C. Bradykinin D. Leukotrienes
A. Platelet-activating factor (PAF) The biologic activity of PAF is virtually identical to that of leukotrienes, namely causing endothelial cell retraction to increase vascular permeability, leukocyte adhesion to endothelial cells, and platelet activation.
Which chemical mediators induce pain during an inflammatory response? A. Prostaglandins and bradykinin B. Tryptase and histamine C. Phospholipase and prostacyclin D. Leukotrienes and serotonin
A. Prostaglandins and bradykinin The primary kinin produced from the kinin system is bradykinin, which causes dilation of blood vessels, acts with prostaglandins to stimulate nerve endings and induce pain, causes smooth muscle cell contraction, increases vascular permeability, and may increase leukocyte chemotaxis
Which of the following is a characteristic of HIV? A. The virus is a retrovirus. B. It only infects T helper cells. C. Five strains have been identified. D. It carries genetic information in DNA.
A. The virus is a retrovirus One particular family of viruses, retroviruses (e.g., HIV) carries an enzyme reverse transcriptase that creates a double-stranded DNA version of the virus.
Hypersensitivity is best defined as a(n): A. altered immunologic response to an antigen that results in disease. B. immunologic reaction of one person to the tissue of another person. C. undetectable immune response in the presence of antigens. D. disturbance in the immunologic tolerance of self-antigens.
A. altered immunologic response to an antigen that results in disease. Hypersensitivity is an altered immunologic response to an antigen that results in disease or damage to the host.
In the clotting cascade, the intrinsic and the extrinsic pathways converge at: A. factor X. B. Hageman factor. C. factor XII. D. factor V.
A. factor X. The coagulation cascade consists of the extrinsic pathway and the intrinsic pathway that converge at factor X.
When histamine binds the histamine-2 (H2) receptor, inflammation is: A. inhibited. B. not changed. C. accelerated. D. activated.
A. inhibited. Binding of histamine to the H1 receptor is essentially proinflammatory, that is, it promotes inflammation. On the other hand, binding to the H2 receptor is generally anti-inflammatory because it results in suppression of leukocyte function.
In a type II hypersensitivity reaction, when soluble antigens from infectious agents enter circulation, tissue damage is a result of: A. neutrophil granules and toxic oxygen products. B. phagocytosis in the spleen. C. complement-mediated cell lysis. D. phagocytosis by macrophages.
A. neutrophil granules and toxic oxygen products. The components of neutrophil granules, as well as the several toxic oxygen products produced by these cells, damage the tissue.
HIV antibodies appear within ______ weeks after infection through blood products. A. 20 to 24 B. 4 to 7 C. 10 to 12 D. 1 to 2
B. 4 to 7 Antibody appears rather rapidly after infection through blood products, usually within 4 to 7 weeks.
_____ may activate the complement system. A. Viruses B. Antigen-antibody complexes C. Mast cells D. Macrophages
B. Antigen-antibody complexes Activation of the classical pathway begins with the activation of protein C1 and is preceded by formation of a complex between an antigen and an antibody to form an antigen-antibody complex (immune complex).
What occurs during the process of repair after tissue damage? A. Regeneration occurs in which original tissue is replaced. B. Destroyed tissue is replaced by nonfunctioning scar tissue. C. Resolution occurs when tissue is regenerated. D. Destroyed tissue is replaced by epithelialization.
B. Destroyed tissue is replaced by nonfunctioning scar tissue. Repair is the replacement of destroyed tissue with scar tissue. Scar tissue is composed primarily of collagen that fills in the lesion and restores tensile strength but cannot carry out the physiologic functions of destroyed tissue.
Which manifestation of inflammation is systemic? A. Redness and heat B. Fever and leukocytosis C. Formation of exudates D. Pain and edema
B. Fever and leukocytosis The three primary systemic changes associated with the acute inflammatory response are fever, leukocytosis (a transient increase in circulating leukocytes), and increased levels in circulating plasma proteins
Which immunoglobulin is present in blood, saliva, breast milk, and respiratory secretions? A. IgM B. IgA C. IgG D. IgE
B. IgA IgA can be divided into two subclasses, IgA1 and IgA2. IgA1 molecules are found predominantly in the blood, whereas IgA2 is the predominant class of antibody found in normal body secretions.
Which antibody indicates a typical primary immune response? A. IgA B. IgM C. IgG D. IgE
B. IgM This is the initial response, or primary immune response. Typically, IgM is produced first, followed by IgG against the same antigen.
When looking at white blood cell differentials, nurses know that individuals have early, acute inflammatory reactions when they notice elevations of which leukocyte? A. Basophils B. Neutrophils C. Eosinophils D. Monocytes
B. Neutrophils Neutrophils are the predominant phagocytes in the early inflammatory site, arriving within 6 to 12 hours after the initial injury, where they ingest (phagocytose) bacteria, dead cells, and cellular debris
Cytokines are thought to raise the thermoregulatory set point to cause fever by stimulating the synthesis of which chemical mediator? A. Histamine B. Prostaglandin C. Leukotriene D. Bradykinin
B. Prostaglandin These cytokines seem to raise the thermoregulatory set point through stimulation of prostaglandin synthesis and turnover in thermoregulatory (brain) and nonthermoregulatory (peripheral) tissue.
Which statement is true about fungal infections? A. They are be prevented by vaccines. B. They are controlled by phagocytes and T lymphocytes. C. They result in release of endotoxins. D. They occur only on skin, hair, and nails.
B. They are controlled by phagocytes and T lymphocytes. The host defense against fungal infection includes the fungistatic properties of neutrophils and macrophages. T lymphocytes are crucial in limiting the extent of infection and producing cytokines to further activate macrophages.
Which are characteristics of exotoxins? A. They can initiate the complement and coagulation cascades. B. They are released during bacterial growth. C. They are contained in cell walls of gram-negative bacteria. D. They are released during the lysis of bacteria.
B. They are released during bacterial growth. Exotoxins are proteins released during bacterial growth.
What process causes heat and redness that occur during the inflammatory process? A. Platelet aggregation B. Vasodilation C. Endothelial cell contraction D. Increased capillary permeability
B. Vasodilation The increased blood flow and increasing concentration of red cells at the site of inflammation cause locally increased warmth and redness.
Blood transfusion reactions are an example of: A. autoimmunity. B. alloimmunity. C. hypersensitivity. D. homoimmunity.
B. alloimmunity. Alloimmunity (also termed isoimmunity) occurs when the immune system of one individual produces an immunologic reaction against tissues of another individual.
The hypersensitivity reaction that occurs after a person who is allergic to bee stings is stung by a bee is called: A. hemolytic shock. B. anaphylaxis. C. systemic erythematosus D. necrotizing vasculitis.
B. anaphylaxis. Examples of systemic anaphylaxis are allergic reactions to bee stings, peanuts, and fish.
Frequently H1 and H2 receptors are located on the same cells and act in a(n) _____ fashion. A. additive B. antagonistic C. synergistic D. agonistic
B. antagonistic Both types of receptors are distributed among many different cells and are often present on the same cells and may act in an antagonistic fashion. For instance, neutrophils express both types of receptors, with stimulation of H1 receptors resulting in the augmentation of neutrophil chemotaxis, and H2 stimulation resulting in its inhibition.
Antibodies protect the host from bacterial toxins by: A. interfering with the DNA enzyme needed for replication. B. binding to the toxins to neutralize their biologic effects. C. inhibiting the synthesis of DNA proteins needed for growth. D. lysing the cell membrane of the toxins.
B. binding to the toxins to neutralize their biologic effects. To cause disease, most toxins must bind to surface molecules on the individual's cells. Protective antibodies can bind to the toxins, prevent their interaction with cells, and neutralize their biologic effects.
The _____ system is a plasma protein system that forms a fibrinous network at an inflamed site to prevent spread of infection to adjacent tissues and keep microorganisms and foreign bodies at the site of greatest inflammatory activity. A. complement B. coagulation C. fibrinolysis D. kinin
B. coagulation The clotting (coagulation) system is a group of plasma proteins that form a fibrinous meshwork at an injured or inflamed site. This (1) prevents the spread of infection to adjacent tissues, (2) traps microorganisms and foreign bodies at the site of inflammation for removal by infiltrating cells (e.g., neutrophils and macrophages), (3) forms a clot that stops bleeding, and (4) provides a framework for future repair and healing.
One systemic manifestation of an acute inflammatory response is fever that is produced by: A. immune complexes acting indirectly on the hypothalamus. B. endogenous pyrogens acting directly on the hypothalamus. C. exogenous pyrogens acting directly on the hypothalamus. D. cytokines acting indirectly on the hypothalamus.
B. endogenous pyrogens acting directly on the hypothalamus. There is little evidence that exogenous pyrogens cause fever directly. Such pyrogens indirectly affect the hypothalamus through endogenous pyrogens released by cells of the host.
The portion of the antigen that is configured for recognition and binding is called an antigenic determinant or a(n): A. paratope. B. epitope. C. antigenitope. D. immunotope.
B. epitope. The precise portion of the antigen that is configured for recognition and binding is called its antigenic determinant, or epitope.
The most important determinant of immunogenicity is the antigen's: A. size. B. foreignness C. complexity. D. quantity.
B. foreignness Foremost among the criteria for immunogenicity is the antigen's foreignness. A self-antigen that fulfills all these criteria except foreignness does not normally elicit an immune response. Thus most individuals are tolerant to their own antigens. The immune system has an exquisite ability to distinguish self (self-antigens) from non-self (foreign antigens).
During an IgE-mediated hypersensitivity reaction, the degranulation of mast cells is a result of the action of _____ receptors. A. chemotactic factor of anaphylaxis bound to B. histamine bound to H2 C. epinephrine bound to mast cell D. acetylcholine bound to mast cell
B. histamine bound to H2 If further exposure of a sensitized individual to the antigen occurs, one molecule of antigen may bind simultaneously to two molecules of IgE-Fc receptor complexes on the mast cell's surface (cross-link) resulting in activation of intracellular signaling pathways and mast cell degranulation (Figure 8-1, B and Chapter 6). The antigen that triggers cross-linking must have at least two antigenic determinants on the same molecule. The most potent mediator is histamine, which affects several key target cells.
Many older adults have impaired inflammation and wound healing because of a(n): A. insufficient number of mast cells. B. underlying chronic illness(es). C. deficiency in complement and chemotaxis. D. circulatory system that cannot adequately perfuse tissues.
B. underlying chronic illness(es). In some cases, impaired healing is not directly associated with aging in general but can instead be linked to a chronic illness such as cardiovascular disease or diabetes mellitus.
After sexual transmission of HIV, a person can be infected yet seronegative for _____ months. (*Weeks*-typo in PAL question) A. 18 to 20 B. 1 to 2 C. 4 to 7 D. 24 to 36
C. 4 to 7 Antibody appears rather rapidly after infection through blood products, usually within 4 to 7 weeks. After sexual transmission, however, the individual can be infected yet seronegative for 6 to 14 months or, in at least one case, for years.
What is the mechanism in type III hypersensitivity reactions? A. Antibodies coat mast cells by binding to receptors that signal its degranulation followed by discharge of preformed mediators. B. Antibodies bind to the antigen on the cell surface. C. Antibodies bind to soluble antigens that were released into body fluids and the immune complexes are deposited in the tissues. D. Cytotoxic T lymphocytes or lymphokine-producing Th1 cells attack and destroy cellular targets directly.
C. Antibodies bind to soluble antigens that were released into body fluids and the immune complexes are deposited in the tissues. Most type III hypersensitivity diseases are caused by antigen-antibody (immune) complexes that are formed in the circulation and deposited later in vessel walls or extravascular tissues.
A keloid is the result of which dysfunctional wound healing response? A. Contraction B. Epithelialization C. Collagen matrix assembly D. Maturation
C. Collagen matrix assembly Both keloids and hypertrophic scars are caused by an imbalance between collagen synthesis and collagen degradation in which synthesis is increased relative to degradation.
Which component of the plasma protein system tags pathogenic microorganisms for destruction by neutrophils and macrophages? A. Immune system B. Clotting system C. Complement cascade D. Kinin system
C. Complement cascade C3b (a component of the complement cascade) adheres to the surface of a pathogenic microorganism and serves as an efficient opsonin. Opsonins are molecules that "tag" microorganisms for destruction by cells of the inflammatory system (primarily neutrophils and macrophages).
A major immunologic finding in AIDS is the striking decrease in the number of which cells? A. Macrophages B. CD8 cells C. Helper T cells D. CD2 cells
C. Helper T cells
Which cytokines are produced and released from virally infected host cells? A. TNF-α B. IL-1 C. IFN-α and IFN-β D. IL-10
C. IFN-α and IFN-β IFNs are produced and released by virally infected cells in response to viral double-stranded RNA. IFN-α and IFN-β induce production of antiviral proteins, thereby conferring protection on uninfected cells. IFN-α or IFN-β is released from virally infected cells and attaches to a receptor on a neighboring cell. Interferons also enhance the efficiency of developing an acquired immune response.
What causes the edema that occurs during the inflammatory process? A. Emigration of neutrophils B. Vasodilation C. Increased capillary permeability D. Endothelial cell contraction
C. Increased capillary permeability The increased flow and capillary permeability result in leakage of plasma from the vessels, causing swelling (edema) in the surrounding tissue.
What effect does chemotactic factor have on the inflammatory process? A. It produces edema around the inflamed area. B. It causes vasodilation around the inflamed area. C. It directs leukocytes to the inflamed area. D. It stimulates smooth muscle contraction in the inflamed area.
C. It directs leukocytes to the inflamed area. Two chemotactic factors, neutrophil chemotactic factor and ECF-A, are also released during mast cell degranulation. Neutrophil chemotactic factor attracts neutrophils, and ECF-A attracts eosinophils to the site of inflammation.
During an IgE-mediated hypersensitivity reaction, what causes bronchospasm? A. Smooth muscle contraction caused by histamine bound to H2 receptors B. Bronchial edema caused by binding of the cytotropic antibody C. Smooth muscle contraction caused by histamine bound to H1 receptors D. Bronchial edema caused by chemotactic factor of anaphylaxis
C. Smooth muscle contraction caused by histamine bound to H1 receptors Acting through the H1 receptors, histamine contracts bronchial smooth muscles, causing bronchial constriction; increases vascular permeability, causing edema; and causes vasodilation, increasing blood flow into the affected area.
What is the last stage in the infectious process? A. Invasion B. Colonization C. Spread D. Multiplication
C. Spread From the perspective of the microorganisms that cause disease, the infectious process undergoes four separate stages of progression: colonization, invasion, multiplication, and spread.
Once they have penetrated the first line of defense, which microorganisms do natural killer (NK) cells actively attack? A. Fungi B. Mycoplasma C. Viruses D. Bacteria
C. Viruses NK cells are the principal defenders against tumor cells or virally infected cells that have down-regulated major histocompatibility complex expression and are therefore not recognized by T-cytotoxic cells. NK cell function is suppressed by targets with surface class I MHC molecules.
B lymphocytes mature and undergo changes that commit them to becoming B cells in the: A. spleen. B. thymus gland. C. bone marrow. D. regional lymph nodes.
C. bone marrow. This process is called the generation of clonal diversity and occurs in specialized (primary) lymphoid organs; the thymus for T cells and the bone marrow for B cells.
A role of NK cells is to: A. proliferate after immunization with antigen. B. initiate the complement cascade. C. eliminate malignant cells. D. bind tightly to antigens.
C. eliminate malignant cells. The main function of NK cells is recognition and elimination of cells infected with viruses, although they are also somewhat effective at elimination of other abnormal host cells, specifically cancer cells.
TNF-α is secreted from: A. mast cells. B. virally infected cells. C. macrophages. D. bacterial infected cells.
C. macrophages. Different kinds of IFNs are produced by different types of cells—macrophages are the primary producers of both IFN-α and IFN-β.
The predominant phagocytic cells in the later stages of an inflammatory response are: A. neutrophils. B. eosinophils. C. monocytes. D. chemokines.
C. monocytes. The next phagocytes on the scene are monocytes and macrophages, which perform many of the same functions as neutrophils but for a longer time and in a later stage of the inflammatory response.
Antibodies are produced in: A. helper T lymphocytes. B. the thymus gland C. plasma cells D. the bone marrow
C. plasma cells An antibody, or immunoglobulin, is a serum glycoprotein produced by plasma cells in response to a challenge by an immunogen.
The primary characteristic that differentiates the immune response from other protective mechanisms is that the immune response is: A. an innate response, rather than acquired. B. a short-term response to a specific pathogen. C. specific to the antigen that initiates it. D. similar each time it is activated.
C. specific to the antigen that initiates it. Unlike inflammation, which is nonspecifically activated by cellular damage as well as pathogenic microorganisms, the immune response is primarily designed to afford long-term specific protection (i.e., immunity) against particular invading microorganisms, that is, it has a "memory" function.
When a person is exposed to most antigens, how long does it take before an antibody can be detected in the circulation? A. 24 hours B. 3 days C. 12 hours D. 6 days
D. 6 days After approximately 5 to 7 days, IgM antibody specific for that antigen can be detected in the circulation.
If a person had very low levels of Ig__, that individual is more susceptible to infections of mucous membranes. A. M B. E C. G D. A
D. A The IgA molecules found in bodily secretions are dimers anchored together through a J-chain and "secretory piece." This secretory piece is attached to the IgAs inside mucosal epithelial cells and may function to protect these immunoglobulins against degradation by enzymes also found in the secretions.
What is the mechanism in type II hypersensitivity reactions? A. Cytotoxic T lymphocytes or lymphokines-producing Th1 cells attack and destroy cellular targets directly. B. Antibodies coat mast cells by binding to receptors that signal its degranulation followed by discharge of preformed mediators. C. Antibodies bind to soluble antigens that were released into body fluids and the immune complexes are deposited in the tissues. D. Antibodies bind to the antigens on the cell surface.
D. Antibodies bind to the antigens on the cell surface. All of these mechanisms begin with antibody binding to tissue specific antigens or antigens that have attached to particular tissues. First, the cell can be destroyed by antibody (IgG or IgM) and activation of the complement cascade through the classical pathway.
What is an outcome of the complement cascade? A. Activates the clotting cascade B. Prevents the spread of infection to adjacent tissues C. Inactivates chemical mediators such as histamine D. Attacks bacterial cell membranes
D. Attacks bacterial cell membranes In summary, the complement cascade can be activated by at least three different means, and its products have four functions: (1) anaphylatoxic activity resulting in mast cell degranulation, (2) leukocyte chemotaxis, (3) opsonization, and (4) cell lysis.
Which secretion transmits the human immunodeficiency virus? A. Urine B. Saliva C. Sweat D. Breast milk
D. Breast milk HIV is a blood-borne pathogen present in body fluids (e.g., blood, vaginal fluid, semen, breast milk).
Which cells are primary targets for HIV? A. CD8-positive Tc cells only B. D4+ Th cells only C. CD8-positive Tc cells and plasma cells D. CD4+ Th cells, macrophages, and NK cells
D. CD4+ Th cells, macrophages, and NK cells The primary cellular targets for HIV include the following: CD4+ Th cells Dendritic cells (depending on the level of chemokine receptors the cell expresses) Macrophages (express low levels of CD4, but high amounts of heparin sulfate proteoglycans [syndecan] and other molecules [CCR5] that bind to gp120 and adsorb HIV) CD8-positive Tc cells (low rate of infection, but CD4 can be expressed by activated CD8-positive Tc cells) ++ Thymic cells (express CD4 and CD8 simultaneously) NK cells (some are CD4+, CCR5+) Neural cells of monocyte origin (macrophages and microglial cells)
The class of antibody involved in type I hypersensitivity reactions is: A. IgG B. IgM C. IgA D. IgE
D. IgE Type I reactions are mediated by antigen-specific IgE and the products of tissue mast cells.
What is function of the complement cascade called opsonization? A. It is the processing of pathogenic microorganisms so that activated lymphocytes can be created for acquired immunity. B. It is the destruction of glycoprotein cell membranes of pathogenic microorganisms. C. It is the anaphylatoxic activity resulting in mast cell degranulation. D. It is the tagging of pathogenic microorganisms for destruction by neutrophils and macrophages.
D. It is the tagging of pathogenic microorganisms for destruction by neutrophils and macrophages. C3b adheres to the surface of a pathogenic microorganism and serves as an efficient opsonin. Opsonins are molecules that "tag" microorganisms for destruction by cells of the inflammatory system (primarily neutrophils and macrophages).
What type of immunity is produced when an immunoglobulin crosses the placenta? A. Active innate B. Passive innate C. Active acquired D. Passive acquired
D. Passive acquired Passive acquired immunity (passive immunity) does not involve the host's immune response at all. Rather, passive immunity occurs when preformed antibodies or T lymphocytes are transferred from a donor to the recipient. This can occur naturally, as in the passage of maternal antibodies across the placenta to the fetus, or artificially, as in a clinic using immunotherapy for a specific disease.
Which chemical interacts among all plasma protein systems by degrading blood clots, activating complement, and activating the Hageman factor? A. Bradykinin B. Kallikrein C. Histamine D. Plasmin
D. Plasmin
Which statement about vaccines is true? A. Most bacterial vaccines contain attenuated organisms. B. Vaccines provide effective protection for all people against viruses, bacteria, and fungal infections. C. Most viral vaccines are made by using dead organisms. D. Vaccines require booster injections to maintain lifelong protection.
D. Vaccines require booster injections to maintain lifelong protection. In general, vaccine-induced protection does not persist as long as infection-induced immunity, thus booster injections may be necessary to maintain protection throughout life.
Which of the following is a vascular effect of histamine released from mast cells? A. Increased endothelial adhesiveness B. Platelet adhesion C. Initiation of the clotting cascade D. Vasodilation
D. Vasodilation C2b affects smooth muscle, causing vasodilation and increased vascular permeability.C3a, C5a, and to a limited extent C4a, are anaphylatoxins, that is, they induce rapid mast cell degranulation (release of granular contents) and the release of histamine (Figure 6-9 ) causing vasodilation and increased capillary permeability.
In a type II hypersensitivity reaction, when mismatched blood is administered causing an ABO incompatibility, the erythrocytes are destroyed by: A. natural killer cells. B. phagocytosis by macrophages. C. phagocytosis in the spleen. D. complement-mediated cell lysis.
D. complement-mediated cell lysis. Erythrocytes are destroyed by complement-mediated lysis in individuals with autoimmune hemolytic anemia or as a result of an alloimmune reaction to ABO-mismatched transfused blood cells.
One systemic manifestation of the acute inflammatory response is fever that is produced by _____ on the hypothalamus. A. antigen-antibody complexes acting B. bacterial endotoxin acting C. exogenous pyrogens acting directly D. endogenous pyrogens acting
D. endogenous pyrogens acting These fever-causing cytokines are known as endogenous pyrogens to differentiate them from pathogen-produced exogenous pyrogens. Pyrogens act directly on the hypothalamus, the portion of the brain that controls the body's thermostat.
Vaccines against viruses are made from: A. purified toxins that have been chemically detoxified without loss of immunogenicity. B. killed organisms or extracts of antigens. C. recombinant pathogenic protein. D. live organisms weakened to produce antigens, which limits controllable infection.
D. live organisms weakened to produce antigens, which limits controllable infection. Most vaccines against viral infections (e.g., measles, mumps, rubella, varicella [chickenpox], rotavirus) contain live viruses that are weakened (attenuated) to continue expressing the appropriate antigens but are unable to establish more than a limited and easily controlled infection.
In a type II hypersensitivity reaction, that is an antibody-dependent cell-mediated cytotoxicity (ADCC), target cells are destroyed by: A. neutrophil granules and toxic oxygen products. B. phagocytosis by macrophages. C. complement-mediated cell lysis. D. natural killer cells.
D. natural killer cells. This mechanism involves a subpopulation of cytotoxic cells that are not antigen specific (natural killer [NK] cells). Antibody on the target cell is recognized by Fc receptors on the NK cells, which release toxic substances that destroy the target cell.
In a type II hypersensitivity reaction, when antibodies are formed against red blood cell antigens of the Rh system, the blood vessels are destroyed by: A. complement-mediated cell lysis. B. neutrophil granules and toxic oxygen products. C. phagocytosis by macrophages. D. phagocytosis in the spleen.
D. phagocytosis in the spleen. Antibodies against platelet-specific antigens or against red blood cell antigens of the Rh system coat those cells at low density, resulting in their preferential removal by phagocytosis in the spleen, rather than by complement-mediated lysis.
One purpose of the inflammatory process is to: A. lyse cell membranes of microorganisms. B. create immunity against subsequent tissue injury. C. provide specific responses toward antigens. D. prevent infection of the injured tissue.
D. prevent infection of the injured tissue. If the epithelial barrier is damaged, a highly efficient local and systemic response (inflammation) is mobilized to limit the extent of damage, protect against infection, and initiate repair of the damaged tissue.
Most antigens react directly with cells of the immune system. True False
False Most antigens must be "processed" because they cannot react directly with cells of the immune system but must be shown or "presented" to the immune cells in a very specific manner.
The role of fibroblasts during the reconstructive phase of wound healing is to: A. provide enzymes that débride the wound bed of dead cells. B. establish connections between neighboring cells and contract their fibers. C. synthesize and secrete collagen and the connective tissue proteins. D. generate new capillaries from vascular endothelial cells around the wound.
C. synthesize and secrete collagen and the connective tissue proteins. Fibroblasts are the most important cells during the reconstructive phase of wound healing because they synthesize and secrete collagen and other connective tissue proteins. Fibroblasts are stimulated by macrophage-derived TGF-β.
Cells in _____ may act as a reservoir in which HIV can be relatively protected from antiviral drugs. A. the thymus gland B. bone marrow C. the central nervous system D. the lungs
C. the central nervous system HIV may persist in regions where the antiviral drugs are not as effective, such as the CNS.
One person with HIV cannot transmit the virus to others until HIV antibodies are detected. True False
False Although the individual may not have antibody, he or she may have virus growing, have virus in the blood and body fluids, and be infectious to others.
Antibodies cannot protect a host against viral infections. True False
False Antibodies are primarily responsible for protection against many bacteria and viruses.
The inflammatory response is the body's first line of defense. True False
False Innate immunity includes two lines of defense: natural barriers and inflammation. Natural barriers are physical, mechanical, and biochemical barriers at the body's surfaces and are in place at birth to prevent damage by substances in the environment and thwart infection by pathogenic microorganisms. If the surface barriers are breached, the second line of defense, the inflammatory response, is activated.
Activated T and B lymphocytes provide innate immunity. True False
False T lymphocytes, B lymphocytes, macrophages, and dendritic cells are involved in acquired immunity.
What antibody mediates many common allergic responses? ___________
IgE IgE is the least concentrated of any of the immunoglobulin classes in the circulation. It appears to have very specialized functions as a mediator of many common allergic responses (see Chapter 8) and in the defense against parasitic infections.
What antibody crosses the placenta? ____________
IgG As a result of selective transport across the placenta, maternal IgG is also the major class of antibody found in blood of the fetus and newborn.
What is the most abundant antigen found in the body? __________
IgG IgG is the most abundant class of immunoglobulins; it constitutes 80% to 85% of those circulating in the body and accounts for most of the protective activity against infections
Antibodies to HIV appear within weeks of transmission through blood products, but within months after sexual transmission. True False
True Antibody appears rather rapidly after infection through blood products, usually within 4 to 7 weeks. After sexual transmission, however, the individual can be infected yet seronegative for 6 to 14 months or, in at least one case, for years.
Colonization is the first stage of infection. True False
True From the perspective of the microorganisms that cause disease, the infectious process undergoes four separate stages of progression: colonization, invasion, multiplication, and spread.
Immunodeficiencies can be congenital or acquired. True False
True Generally, the mutations are sporadic and not inherited: a family history exists in only about 25% of individuals. The sporadic mutations occur before birth, but the onset of symptoms may be early or later, depending on the particular syndrome.
Diseases caused by fungi are called mycoses. True False
True Infection with a fungus is called mycosis.
Some forms of severe combined immune deficiency can be caused by a single gene defect. True False
True Most primary immune deficiencies are the result of a single gene defect.
Antibody appears rather rapidly after infection through blood products, usually within 4 to 7 weeks. After sexual transmission, however, the individual can be infected yet seronegative for 6 to 14 months or, in at least one case, for years. True False
True Those with the early stages of HIV disease (early stage disease or clinical latency) are usually asymptomatic. The early stage may last as long as 10 years in untreated people, during which viral load increases and numbers of CD4+ cells progressively decrease. As a result of these processes the level of T cells decreases (particularly memory T cells, which seem more susceptible to HIV infection), thymic production of new T cells is decreased, and the secondary lymphoid organs (particularly the lymph nodes) are damaged.
Viruses have no metabolism and are incapable of independent reproduction. True False
True Viruses are extremely simple microorganisms and do not possess any of the metabolic organelles found in prokaryotes (e.g., bacteria) or eukaryotes (e.g., human cells). Once bound, the virion penetrates the plasma membrane by receptor-mediated endocytosis, by envelope fusion with the plasma membrane, or by directly crossing the plasma membrane. Within the cytoplasm the virus uncoats the protective nucleocapsid and releases viral genetic information. Most RNA viruses directly produce mRNA, which is translated into viral proteins, and genomic RNA, which is eventually packaged into new viruses.
An antigen that is capable of inducing an immune response is called an immunogenic. True False
True An antigen that is immunogenic will induce an immune response resulting in the production of antibodies or functional T cells.
Each individual T and B lymphocyte specifically recognizes only one particular antigen. True False
True Each T or B cell specifically recognizes only one particular antigen, but the sum of the population of lymphocyte specificities may represent millions of foreign antigens
Major histocompatibility complex (MHC) molecules are located on the surface of all body cells except erythrocytes. True False
True MHC molecules are glycoproteins found on the surface of all human cells except red blood cells.
The helper T cell (Th) interacts with immunocompetent B cells causing the production of plasma cells. True False
True Th cells interact with either immunocompetent B or T cells to enhance their response to antigen, which results in differentiation into either plasma cells or effector T cells.