Patho PrepU Chapter 15
A mother brings her 5-month-old infant to the pediatrician for recurrent colds. The mother has never breastfed and the infant is fed iron-fortified formula. The mother asks, "My baby has been perfectly healthy up until last month--now it seems like she has been sick constantly. Why?" How should the physician respond?
"An infant gets immunity from the mother at birth and from breast milk; this provides protection from infection but wears off in approximately 3 to 6 months. An infant still needs time for his own immune system to mature." Explanation: The infant's immune system is not yet mature. Passive immunity is immunity transferred from mother to fetus before birth. After birth, the neonate receives IgG antibodies from the mother in breast milk or colostrum. Therefore, infants are provided with some degree of protection from infection for approximately 3 to 6 months, giving their own immune systems time to mature.
A student states, "It seems like helper T cells do a lot more than just 'help' the cellular immunity process". Which of the following responses listed below best conveys an aspect of the role of CD4+ helper T cells in immunity?
"Helper T cells play a major role in stimulating and regulating the whole process." Explanation: Helper T cells are central to the regulation, proliferation and stimulation of the immune system. They do not play a central role in antigen presentation or early hematopoiesis, however. Their absence would not result in incorrect antibody production, but rather insufficient or absent immune response.
A nurse is teaching a new mother diagnosed with HIV about the transfer of the infection to her newborn. The mother begins to cry and states, "It's too late, the lab tests on my baby are already positive for HIV." How should the nurse respond?
"Just because the test is positive for HIV does not mean your baby is infected with the virus." Explanation: Because of maternal transfer of IgG antibodies to the fetus, an infant born to a mother infected with HIV has a positive HIV antibody test result although the child may not be infected with the virus
A client who was exposed to hepatitis A at a local restaurant has recovered from the disease. At her annual physical, the client asks the health care provider if she should go to her health department and get the hepatitis A "shot." The best response, based on the concepts of adaptive immunity, by the health care provider would be:
"No, since having an active case, you have already developed antigens against hepatitis A." Explanation: The adaptive immune system consists of two groups of lymphocytes and their products, including antibodies. Whereas the cells of the innate immune system recognize structures shared by classes of microorganisms, the cells of the adaptive immune system are capable of recognizing numerous microbial and noninfectious substances and developing a unique specific immune response for each substance. Substances that elicit adaptive immune responses are called antigens. A memory of the substance is also developed so that a repeat exposure to the same microbe or agent produces a quicker and more vigorous response. The hepatitis A virus does not change from year to year. The vaccine does not damage the liver; however, the active hepatitis A disease can.
While explaining immunity to a client, the nurse responds, "The body's internal organs are protected from pathogens because:
"Our mucosal tissue contains all the necessary cell components to fight a pathogen with an immune response." Explanation: Secondary lymphoid tissues contain all the necessary cell components (i.e., T cells, B cells, macrophages, and dendritic cells) for an immune response. Because of the continuous stimulation of the lymphocytes in these tissues by microorganisms constantly entering the body, large numbers of plasma cells are evident. Immunity at the mucosal layers helps to exclude many pathogens and thus protects the vulnerable internal organs. Although cells of both the innate and adaptive immune systems communicate critical information by cell-to-cell contact, many interactions and effector responses depend on the secretion of short-acting soluble molecules called cytokines. The actions of cytokines are often pleiotropic and redundant. Pleiotrophism refers to the ability of a cytokine to act on different cell types.
A sixth grade science teacher asks the students to explain the role of cilia in the lower respiratory tract. Which student response is the best?
"These little hairs move germs trapped in mucous toward the throat so the body can cough them out." Explanation: Also in the lower respiratory tract, hair-like structures called cilia protrude through the epithelial cells. The synchronous action of the cilia moves many microbes trapped in the mucous toward the throat. The physiologic responses of coughing and sneezing further aid in their removal from the body. Chemical defenses against trapped microbes include the following: lysozyme, which is a hydrolytic enzyme capable of cleaving the walls of bacterial cells; complement, which binds and aggregates bacteria to increase their susceptibility to phagocytosis or disrupt their lipid membrane; and members of the collectin family of surfactant proteins in the respiratory tract. The best-defined function of the surfactants is their ability to opsonize pathogens, including bacteria and viruses, and to facilitate phagocytosis by innate immune cells such as macrophages.
A patient with infectious mononucleosis asks the nurse why the lymph nodes are enlarged. Which of the following is the nurse's appropriate response?
"Your lymph nodes trap and destroy viruses." Explanation: The lymph nodes remove foreign material from the lymph system before the fluid can enter the bloodstream. Mononucleosis is an infection caused by the Epstein-Barr virus. The lymph nodes trap the virus where the lymphocytes and macrophages can destroy it. Enlargement may occur with increased production of lymphocytes, backup of lymph fluid, or malignancy.
A middle school student is scheduled to receive booster immunizations and the father asks the nurse why the booster is necessary. What characteristic of the adaptive immune system listed below would provide the rationale for the nurse's response?
A secondary response causes a sharp rise in antibody levels. Explanation: Booster immunizations take advantage of the increase in antibodies that accompanies a repeat exposure. The primary immune response cannot be repeated, and antibodies survive beyond several months. Antigen receptors on CD4+ cells do not require multiple exposures.
Which of the following phenomena would be least likely to result in activation of the complement system?
Activation of toll-like receptors (TLRs) on complement proteins. Explanation: Toll-like receptors are not associated with the complement system. The complement system may be activated by antibody recognition, mannose-binding or microbial protein recognition.
The nurse is administering a measles, mumps, and rubella (MMR) vaccination to a pediatric client. When the nurse explains immunity to the mother, which type of immunity will she explain that this vaccination provides?
Active artificial immunity Explanation: Active immunity is acquired when the host mounts an immune response to an antigen either through the process of vaccination (artificial means) or from environmental exposure (natural means). It is called active immunity because it requires the host's own immune system to develop an immunological response. The process by which active immunity is acquired through the administration of a vaccine is termed immunization. An acquired immune response can improve on repeated exposures to an injected antigen (booster vaccines) or a natural infection.
A client is brought to the physician's office with a raised red macular rash on the trunk and arms accompanied by a fever. A diagnosis of measles is made. Which type of immunity does this disease process provide?
Active natural immunity Explanation: Active immunity is acquired when the host mounts an immune response to an antigen either through the process of vaccination (artificial means) or from environmental exposure (natural means). It is called active immunity because it requires the host's own immune system to develop an immunological response.
Which of the following clients is at the greatest risk for developing an intracellular pathogen infection?
An AIDS client with a decreased CD4+ TH1 count Explanation: Thus, the CD4+ TH1 cell controls and coordinates host defenses against certain intracellular pathogens, a function that helps to explain why a decreased CD4+ TH1 count in persons with acquired immunodeficiency syndrome (AIDS) places them at high risk for intracellular pathogen infections. If the teenager has a healthy immune system, high school should not place him or her at high risk for infection. A WBC of 8000 is normal. Radioactive iodine attacks the thyroid gland and does not usually interfere with immunity.
The cells that mediate humoral immunity do so because they are capable of producing:
Antibodies Explanation: B lymphocytes (B cells) are the only cells capable of producing antibodies; therefore, they are the cells that mediate humoral immunity. B lymphocytes (B cells) differentiate into plasma cells that produce the needed immunoglobulins (antibodies) for responding to that particular antigen. Stem cells are undifferentiated cells. T helper cells differentiate into cytotoxic and other T-cell forms.
Substances foreign to the host that can stimulate an immune response are known as:
Antigens Explanation: Antigens are foreign substances that stimulate an immune response. Antibodies are innate and will adapt to the antigen. MHC proteins aid in the identification process of host cells. Cytokines are signaling molecules of the immune system.
Select the type of lymphocyte that matures in the bone marrow.
B lymphocytes Explanation: B lymphocytes mature in the bone marrow and are essential for humoral or antibody-mediated immunity. The T lymphocytes mature in the thymus. Macrophages are part of the monocytic phagocyte system and are in almost all tissues and are the mature form of monocytes. Cytotoxic T cells are involved in cell-mediated immunity
Cell-mediated immunity is involved in resistance to infectious diseases caused by bacteria and some viruses. It is also involved in cell-mediated hypersensitivity reactions. Which of these does not cause a cell-mediated hypersensitivity reaction?
Blood transfusion Explanation: Activation of macrophages ensures enhanced phagocytic, metabolic, and enzymatic potential, resulting in more efficient destruction of infected cells. This type of defense is important against intracellular pathogens such as Mycobacterium species and Listeria monocytogenes. Contact dermatitis due to a poison ivy reaction or sensitivity to dyes is an example of delayed or cell-mediated hypersensitivity caused by hapten-carrier complexes. Blood transfusions do not cause hypersensitivity reactions by hapten-carrier complexes.
A patient receiving chemotherapy has a leukopenia. Which of the following types of medication would promote long-term improvement in the patient's immune response?
Colony-stimulating factor (CSF) Explanation: CSFs stimulate hematopoiesis of red blood cells, platelets, and white blood cells. A live vaccine might cause an infection in a client with a weakened immune system because the system has too few cells to respond rapidly. An antiretroviral agent may reduce destruction of lymphocytes but does not stimulate increased production. IgG is an antibody that can provide passive immunity when injected but will only provide temporary improvement in immunity.
Cytokines that stimulate bone marrow pluripotent stem and progenitor or precursor cells to produce large numbers of platelets, erythrocytes, lymphocytes, neutrophils, and monocytes, eosinophils, basophils, and dendritic cells are known as:
Colony-stimulating factors (CSFs) Explanation: Colony-stimulating factors (CSFs) are cytokines that stimulate bone marrow pluripotent stem and progenitor or precursor cells to produce large numbers of platelets, erythrocytes, lymphocytes, neutrophils, monocytes, eosinophils, basophils, and dendritic cells. Chemokines are cytokines that stimulate the migration and activation of immune and inflammatory cells. Antibodies are immunoglobulins. NK cells are a class of lymphocytes that recognize infected and stressed cells and respond by killing these cells.
A lactation nurse visits a new mother after delivery of her first child and encourages the mother to breastfeed her infant, even for a short time. Which statement made by the nurse correctly explains the importance of breastfeeding?
Colostrum will provide the infant with passive immunity for several months to diseases to which the mother has immunity. Explanation: After birth, the neonate receives IgG antibodies from the mother in breast milk or colostrum. Therefore, infants are provided with some degree of protection from infection for approximately 3 to 6 months, giving their own immune systems time to mature. IgA is primarily a secretory Ig that is found in saliva, tears, colostrum (i.e., first milk of a nursing mother), and bronchial, gastrointestinal, prostatic, and vaginal secretions. Its primary function is in local immunity on mucosal surfaces. IgA prevents the attachment of viruses and bacteria to epithelial cells
Which of the types of T cells is responsible for destroying pathogens by punching holes in their cell membrane and by secreting cytokines/lymphokines?
Cytotoxic T cells Explanation: Cytotoxic T cells destroy the pathogens. Regulatory T cells suppress immune response. Memory T cells are derived from normal T cells. The principal cells of the adaptive immune system are the T and B lymphocytes and antigen-presenting cells. T lymphocytes differentiate into helper T and regulatory T cells and cytotoxic T cells and provide cell-mediated immunity. CD4+ helper T cells serve as a trigger for the immune response and are essential for the differentiation of B cells into antibody-producing plasma cells and the differentiation of T lymphocytes into CD8+ cytotoxic T cells.
The nurse knows high incidences of infectious illnesses among the older adults who reside in a long term care facility are most likely to have diminished immune capacity because of:
Decreased numbers and responsiveness of T lymphocytes Explanation: Although this phenomenon is not well understood, increasing proportions of lymphocytes become unresponsive with age, and CD4+ T lymphocytes are the most severely affected. B lymphocytes recognize more antigens, not fewer, and expression of cytokines and their cellular receptors decreases
A nurse researcher is developing an experiment to evaluate the causes of inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. Testing which of the following antigen presenting cells should be included in the study?
Dendritic (DC) cells Explanation: Dendritic cells (DCs) are found in the mucosal lining of the bowel and have been implicated in the development of inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, where they present antigens to the B and T lymphocytes through the production of proinflammatory cytokines.
A clinical research study is evaluating cells that bridge both the innate and adaptive immune systems. A nurse has identified the dendritic cells (DCs) as a key component. Which of the following statements validates this finding?
Dendritic cells (DCs) directly sense pathogens, capture foreign agents, and transport them to secondary lymphoid tissues. Once activated, they undergo a maturation process and function as antigen-presenting cells (APCs) capable of initiating adaptive immunity. Explanation: Dendritic cells (DCs) are specialized, bone marrow-derived leukocytes found in lymphoid tissue and are the bridge between the innate and adaptive immune systems. They are present primarily in an immature form that is available to directly sense pathogens, capture foreign agents, and transport them to secondary lymphoid tissues. Once activated DCs undergo a complex maturation process in order to function as key antigen-presenting cells (APCs) capable of initiating adaptive immunity. They are responsible for the processing and presentation of foreign antigens to the lymphocytes.
During a blood transfusion, a client begins to have chills, back pain and develops a fever. The nurse determines the client is experiencing a transfusion reaction. The nurse educates the client about transfusion reactions. Which of the following statements indicates the cause of the reaction?
Each person has two HLA haplotypes that identify human cells. Blood typing involves the identification of these haplotypes (ABO compatibility). The closer the matching of HLA types, the greater is the probability of identical antigens and the lower the chance of rejection. A reaction occurs if the immune system views the HLA types as foreign. Explanation: Human leukocyte antigens (HLAs) are the major target involved in rejection. Each person inherits one chromosome from each parent, supplying two HLA haplotypes. Blood typing involves the identification of these haplotypes. In transplantation, the closer the matching of HLA types, the greater is the probability of identical antigens and the lower the chance of rejection. A reaction occurs if the blood types do not exactly match and the immune system views the HLA types as foreign
Select the statement that best describes the effectiveness of vaccination in the elderly population.
Experimental evidence suggests that vaccination is less successful in inducing immunization in older persons than in younger adults. Explanation: Elderly persons tend to be more susceptible to infections, have more evidence of autoimmune and immune complex disorders than younger persons, and have a higher incidence of cancer. Experimental evidence suggests that vaccination is less successful in inducing immunization in older persons than in younger adults. However, the effect of altered immune function on the health of elderly persons is clouded by the fact that age-related changes or disease may affect the immune response.
The laboratory finds IgA in a sample of cord blood from a newborn infant. This finding is important because it signifies what?
Fetal reaction to exposure to an intrauterine infection Explanation: Cord blood does not normally contain IgM or IgA. If present, these antibodies are of fetal origin and represent exposure to intrauterine infection.
A client diagnosed with sepsis has a critically low neutrophil count. The nurse expects which drug or drug class to be used to stimulate white blood cell production?
Granulocyte CSF (G-CSF) such as filgrastim (Neupogen) Explanation: Granulocyte CSF (G-CSF) promotes growth and maturation of neutrophils consumed in inflammatory reactions. In clinical practice, recombinant CSF is being used to increase the success rates of bone marrow transplantations and neutropenia. The availability of recombinant CSFs and cytokines offers the possibility of several clinical therapies where stimulation or inhibition of the immune response or cell production is desirable.
A 10 year old child with strep throat asks the nurse, "why are there large bumps [lymph nodes] on their neck when their throat gets sore?" The nurse replies that lymph nodes:
Help your body fight off infections by allowing special cells [lymphocytes and macrophages] move through the lymph chain and engulf and destroy germs.
A patient with end-stage kidney disease is receiving a kidney donated by a family member. When caring for this patient, what does the nurse know is the major target involved in organ transplant rejection?
Human leukocyte antigens (HLAs) Explanation: The first human MHC proteins discovered are called human leukocyte antigens (HLAs) and are so named because they were identified on the surface of white blood cells. HLAs are the major target involved in organ transplant rejection and as a result are the focus of a great deal of research in immunology.
An essential property of the immune system is self-regulation. An immune response that is not adequate can lead to immunodeficiency, while an immune response that is excessive can lead to conditions from allergic responses all the way to autoimmune diseases. Which of these is not an example of a breakdown of the self-regulation of the immune system?
Huntington disease Explanation: Self-regulation is an essential property of the immune system. An inadequate immune response may lead to immunodeficiency, but an inappropriate or excessive response may lead to conditions varying from allergic reactions to autoimmune diseases. All answers are autoimmune diseases except for Huntington disease.
A patient receives an interleukin-2 (IL-2) infusion to treat cancer. Which of the following responses explains how this cytokine will affect the growth of cancer cells?
IL-2 stimulates growth of cytotoxic T lymphocytes. Explanation: Cytokines are small proteins used by the innate and adaptive immune systems to communicate with each other. IL-2 is a growth factor for activated T cells produced by macrophages. IL-2 activates cytotoxic T lymphocytes and natural killer cells. These cells destroy abnormal cells
A client comes to the clinic with reports of runny nose, itchy eyes and congestion due to seasonal allergies. The nurse teaches the client about the allergic reaction. The nurse knows that teaching has been effective when the client identifies which CD4 helper T-cell cytokine as the cause of this Type I hypersensitivity reaction?
IL-4 Explanation: T cells produce IL-4, which induces differentiation toward the T2H subtype. The T2H cells direct B lymphocytes to switch class and produce the IgE antibodies and prime the mast cell, which causes an allergic or hypersensitivity response.
The nurse is assisting a new mother with breastfeeding. What does the nurse understand is a primary secretory Ig that is found in the colostrum?
IgA Explanation: IgA is primarily a secretory Ig that is found in saliva, tears, colostrum, and bronchial, gastrointestinal, prostatic, and vaginal secretions. Because it is found in secretions, its primary function is in local immunity on mucosal surfaces. IgA prevents the attachment of viruses and bacteria to epithelial cells.
A client experiences an allergic reaction. Select the immunoglobulin that would bind to mast cells and release histamine.
IgE Explanation: IgE responds to allergic exposures and parasitic infections. IgA is the primary defense against local infections in mucosal tissues. IgG protects against bacteria, toxins, and viruses and activates the complement system. IgD acts as an antigen receptor for initiating the B cells.
Which of the following immunoglobulins (Ig) is released in response to allergy or parasitic infections?
IgE Explanation: IgG is responsible for antiviral, antitoxin, and antibacterial responses. IgA is found in body secretions and helps with local immunity on mucosal surfaces. IgM is the first antibody developed by an infant. IgE is secreted in response to inflammation and allergy and is released in the presence of parasitic infection. IgD helps B cells mature.
The nurse is aware that the only class of immunoglobulins to cross the placenta is:
IgG Explanation: IgG is the only class of immunoglobulins to cross the placenta. Levels of maternal IgG decrease significantly during the first 3 to 6 months of life, while infant synthesis of immunoglobulins increases.
Which of the following immunoglobulins (Ig) is the most abundant of circulating antibodies?
IgG Explanation: IgG makes up about 75% of the immunoglobulins. IgA is about 15%, IgM 10%, and IgE 0.004% of the total
Three days ago, a mother delivered her full-term infant who had been identified as having an in utero infection. The infant is receiving antibiotic and phototherapy, and the mother is breastfeeding. Which of the following types of immunoglobulins could most reasonably be expected to predominate in the infant's immune system?
IgG, IgA, IgM Explanation: Infants are born with IgG from transfer across the placenta, while IgA is found in colostrum. IgM is indicative of an in utero infection.
The nurse is reviewing the functions of immunoglobulins and determines which of the following as a correct action?
IgM/first to challenge the antigen Explanation: The correct actions are as follows: IgM is the first circulating immunoglobulin to appear in response to an antigen. IgA prevents the attachment of viruses and bacteria to epithelial cells. IgE is involved in inflammation, allergic responses, and combating parasitic infections. It binds to mast cells and basophils. IgD serves as an antigen receptor for initiating the differentiation of B cells.
The most important function of the thymus is:
Immune cell production and maturation Explanation: The function of the thymus as a lymphoid organ is to generate mature immunocompetent T lymphocytes. The lymph nodes remove foreign material from lymph before it enters the bloodstream and serve as a center for proliferation and response of immune cells. The spleen filters antigens from the blood and responds to systemic infections.
A client tells the nurse she is at risk to prematurely deliver her baby and is concerned that the baby does not have a developed immune system. The best response would be:
Infants born prematurely may be deficient immunity. Explanation: The largest amount of IgG crosses the placenta during the last weeks of pregnancy and is stored in fetal tissues; therefore, infants born prematurely may be deficient
Select the phases that makeup the reaction of the complement system.
Initial activation, amplification of inflammation, and membrane attack response Explanation: The reactions of the complement system can be divided into three phases: (1) initial activation, (2) amplification of inflammation, and (3) membrane attack response. The other options are not part of the system
Natural killer cells are specialized lymphocytes that are one of the major parts of which immunity?
Innate Explanation: The major components of innate immunity are the skin and mucous membranes; phagocytic cells (mainly neutrophils and macrophages); specialized lymphocytes called NK cells; and several plasma proteins, including the proteins of the complement system. Adaptive, humoral, and cell-mediated immunities do not use NK cells.
The nurse knows which of the following components listed below is needed for long lasting immunity in a client with a diagnosis of sepsis without the causative agent identified?
Lymphocytes Explanation: Lymphocytes provide lifelong immunity and an antigen-specific response to harmful microorganisms. Neutrophils, macrophages, and natural killer cells do not provide this.
A 53-year-old female hospital patient has received a kidney transplant following renal failure secondary to hypertension. As part of the teaching while she was on the organ wait list, she was made aware that she would need to take anti-rejection drugs for the rest of her life. Which aspect of the immune system underlies this necessity?
MHC molecules will never develop in the cells of the donor organ and effector cells will be continually stimulated. Explanation: The lack of familiar MHC molecules will stimulate an immune response by effector cells in the absence of anti-rejection drugs. An innate immune response is not central to the response, but rather the adaptive immune system. Lack of known MHC molecules, not foreign antibodies, accounts for the immune response, and familiar MHC molecules will not be produced by the donor kidney cells
A person has been exposed to a particular antigen and a now experiences a repeat exposure. What stimulates a quicker immune response?
Memory T cells Explanation: The memory T and B lymphocytes that are generated remain in the body for a longer time and can respond more rapidly during repeat exposures to an antigen related to their acquired memory.
While caring for a pediatric client admitted with a viral infection, the nurse knows that which type of cell will be the child's primary defense against the virus?
Natural killer (NK) cells Explanation: The third type of lymphocyte, the natural killer (NK) cell is part of the innate immune system and may be the first line of defense against viral infections. The NK cell also has the ability to recognize and kill tumor cells, abnormal body cells, and cells infected with intracellular pathogens, such as viruses and intracellular bacteria. Complement is activated in the inflammatory response. Leukotrienes and bradykinin are also a part of the inflammatory response.
While caring for a pediatric client admitted with a viral infection, the nurse knows that which type of cell will be the child's primary defense against the virus?
Natural killer (NK) cells Explanation: The third type of lymphocyte, the natural killer (NK) cell is part of the innate immune system and may be the first line of defense against viral infections. The NK cell also has the ability to recognize and kill tumor cells, abnormal body cells, and cells infected with intracellular pathogens, such as viruses and intracellular bacteria. Complement is activated in the inflammatory response. Leukotrienes and bradykinin are also a part of the inflammatory response.
A child has a congenital condition in which the thymus gland is absent. What should the nurse include in the education of care of this patient to the parents?
Observe and report signs and symptoms of infection. Explanation: The thymus is essential to the development of the immune system because it is responsible for the production of mature, immunocompetent T lymphocytes.
The process by which microbes are coated to allow for more efficient recognition by phagocytes is known as:
Opsonization Explanation: Opsonization is the coating of particles with proteins, lectins, and complement to make them more attractive for phagocytes to recognize them as a foreign pathogen. Immunization is the process of acquiring the ability to respond to an antigen after its administration by vaccine. Immunity is protection from disease and, more specifically, infectious disease. Memory response occurs on second or subsequent exposures to the antigen
The C3b subcomponent of the complement system does which of the following?
Opsonizes microbes to facilitate phagocytosis Explanation: C3b is a key opsonin that coats bacteria and allows them to be phagocytized.
While explaining immunity to a client, the nurse responds, "The body's internal organs are protected from pathogens because:
Our mucosal tissue contains all the necessary cell components to fight a pathogen with an immune response." Explanation: Secondary lymphoid tissues contain all the necessary cell components (i.e., T cells, B cells, macrophages, and dendritic cells) for an immune response. Because of the continuous stimulation of the lymphocytes in these tissues by microorganisms constantly entering the body, large numbers of plasma cells are evident. Immunity at the mucosal layers helps to exclude many pathogens and thus protects the vulnerable internal organs. Although cells of both the innate and adaptive immune systems communicate critical information by cell-to-cell contact, many interactions and effector responses depend on the secretion of short-acting soluble molecules called cytokines. The actions of cytokines are often pleiotropic and redundant. Pleiotrophism refers to the ability of a cytokine to act on different cell types.
A woman experiences a viral infection while pregnant. Which of the following types of immunity does an infant have at birth against this infection?
Passive Explanation: Active immunity is acquired through exposure to antigens and having the B and T lymphocytes develop a response. Passive immunity is when the antibodies against an antigen are transferred directly to the host, such as when a fetus gains from the mother's immune system. Tolerance is the ability of the immune system to react to foreign substances but not the body cells. Adaptive immunity is when the immune system responds to antigens and is moderated by B and T lymphocytes.
A client who has a diagnosis of an autoimmune disease asks his nurse why it is that their immune system does not attack all of the cells that make up his body. Which of the following aspects of pathogen recognition in the innate immune system listed below would underlie the nurse's response?
Pattern recognition receptors (PRRs) ensure cells are correctly identified. Explanation: PRRs recognize the structure of invaders and thus prevent activation by healthy somatic cells, though neither intraepithelial lymphocytes nor natural killer cells possess the high level of specification and diversity of receptors associated with the adaptive immune system. Host cells do not excrete inhibitory proteins and PAMPs exist on pathogens, not leukocytes.
The nurse is planning care for a client with a diagnosis of primary immunodeficiency. Which of the following is a priority intervention to incorporate into the plan?
Protecting the client from infection Explanation: The client with immunodeficiency has an absent or inadequate immune response. Cell-mediated, or cellular, immunity is mediated by the cytotoxic T lymphocytes (T cells) and functions in the elimination of intracellular pathogens. A lack of this response increases the client's risk of infection.
A client is being evaluated for atopic dermatitis possibly caused by a latex-related allergic reaction. The nurse will review which of the following labs to determine if an allergy is present?
Serum IgE Explanation: IgE binds to mast cells and basophils and is involved in parasitic infections, allergic and hypersensitivity reactions. Serum IgE causes the symptoms of allergic reactions and is elevated in type 1 hypersensitivity disorders
The first physical line of defense in innate immunity is:
Skin and mucous membranes Explanation: The first physical line of defense are the skin and mucous membranes, which prevent pathogens from entering. Plasma proteins, neutrophils, and specialized lymphocytes are examples of cellular level protection.
A client has been identified as having an excess of macrophage inhibitory factor, causing the client to have inhibited movement and activity of macrophages. Which of the following processes listed below would the health care team member expect to remain unaffected?
Specificity and memory of the immune response Explanation: Specificity and memory are the defining characteristics of the adaptive immune system, and macrophages do not perform this particular role. Amplification of the immune response, destruction of virus-infected or tumor cells and initiation of adaptive immunity are all components of macrophage activity
A client has immunity that was mediated by specific T lymphocytes and provides defense against intracellular microbes such as viruses. This immunity is recognized as:
T lymphocytes Explanation: Cellular immunity is mediated by cells, such as specific T lymphocytes, and defense against intracellular microbes such as viruses. Histamine is released when the binding of antigen to mast cell- or basophil-bound IgE triggers a response. B cells mediate humoral immunity, and antibodies are produced by cells called B lymphocytes.
Which of the following explains how T lymphocytes and B lymphocytes differ?
T lymphocytes mature in the thymus gland; B lymphocytes mature in the bone marrow. Explanation: T lymphocytes mature in the thymus gland and provide cell-mediated immunity. T lymphocytes activate other lymphocytes and phagocytes. B lymphocytes mature in the bone marrow and are responsible for forming the antibodies that provide humoral immunity. Both are amplified by cytokines.
The nurse knows the cells primarily programmed to remove the invading organisms and remember the antigen to respond rapidly during the next exposure are:
T-and B-lymphocytes. Explanation: T- and B- lymphocytes are unique in that they are the only cells in the body capable of recognizing specific antigens present on the surfaces of microbial agents and other pathogens.
A student asks, "What does cell-mediated immunity mean to the client?" The instructor responds. "This means:
The body is trying to defend itself against intracellular microbe invasion by engulfing and destroying the microbe." Explanation: Cell-mediated immunity, which defends against intracellular microbes such as viruses, is provided by cells called T lymphocytes. Some T lymphocytes activate phagocytes to destroy microbes that have been engulfed, whereas others kill any type of host cell that is harboring microbes.
A student asks, "What does cell-mediated immunity mean to the client?" The instructor responds. "This means:
The body is trying to defend itself against intracellular microbe invasion by engulfing and destroying the microbe." Explanation: Cell-mediated immunity, which defends against intracellular microbes such as viruses, is provided by cells called T lymphocytes. Some T lymphocytes activate phagocytes to destroy microbes that have been engulfed, whereas others kill any type of host cell that is harboring microbes.
Following delivery, the parents have chosen to have their infant's cord blood frozen. A blood test is performed on the cord blood and found to contain IgM antibodies. The nurse interprets this to mean:
The infant has been exposed to an intrauterine infection. Explanation: Protection of a newborn against antigens occurs through transfer of maternal antibodies. Maternal IgG antibodies cross the placenta during fetal development and remain functional in the newborn for the first months of life. IgG is the only class of immunoglobulins to cross the placenta. Cord blood does not normally contain IgM or IgA. If present, these antibodies are of fetal origin and represent exposure to intrauterine infection.
A newborn has been lethargic, is not nursing well, and is basically looking ill. Following lab tests, it has been found that the newborn has IgM present in his blood. How should the nurse interpret this finding?
The presence of IgM suggests the infant has a current infection. Explanation: IgM is the first immunoglobulin to appear in response to antigen and is the first antibody type made by a newborn. This is diagnostically useful because the presence of IgM suggests a current infection in the infant by a specific pathogen. IgE is involved in inflammation, allergic responses, and combating parasitic infections. It binds to mast cells and basophils. The binding of antigen to mast cell- or basophil-bound IgE triggers these cells to release histamine and other mediators important in inflammation and allergies. IgA is found in saliva and tears, and is a primary defense against infections in mucosal tissues.
One of the self-regulatory actions of the immune system is to identify self-antigens and be nonreactive to them. What is this ability of the immune system defined as?
Tolerance Explanation: The term tolerance is used to define the ability of the immune system to be nonreactive to self-antigens while producing immunity to foreign agents. All other responses have nothing to do with the recognition and tolerance to self-antigens.
A patient seeks treatment in the clinic for exposure to poison ivy with a rash over the right arm and hand. The nurse is aware that what toxin is found in the oils on poison ivy that are responsible for eliciting an allergic reaction?
Urushiol Explanation: Urushiol is a toxin found in the oils on poison ivy that is responsible for initiating an allergic reaction.
A client comes to the clinic with the following cardinal signs of inflammation: redness, heat, pain and swelling, following a laceration to the thigh. Which of the following statements correctly explains the cause of swelling at the laceration site?
When activated, the complement protein C3 breaks into two fragments. The larger 3b fragment acts as an enzyme to cleave C5 into two components the C5a fragment produces vasodilation and increases vascular permeability causing edema. Explanation: The central component of complement is the activation of the complement protein C3 and its enzymatic cleavage into a larger C3b fragment and a smaller C3a fragment. The smaller 3a fragment stimulates inflammation by acting as a chemoattractant for neutrophils. The larger 3b fragment acts as an enzyme to cleave C5 into two components the C5a fragment produces vasodilation and increases vascular permeability causing edema
A mother is diagnosed with a bacterial infection and is worried that her newborn infant will also contract the infection. Which of the following statements should the nurse include in the teaching plan for the client?
Your newborn has maternal IgG antibodies that were transferred through the placenta before birth, providing some protection from infection. Explanation: Passive immunity is immunity transferred from another source. The most common form of passive immunity is that conferred from mother to fetus. During fetal development, maternal IgG antibodies are transferred to the fetus via the placenta. After birth, the neonate also receives IgG antibodies from the mother in breast milk or colostrum. Therefore, infants are provided with some degree of protection from infection for approximately 3 to 6 months, giving their own immune systems time to mature.
The nurse knows a drug in a category identified as a colony-stimulating factor (CSF) helps:
to stimulate bone marrow to produce large numbers of mature cells such as platelets and erythrocytes. Explanation: CSFs participate in hematopoiesis by stimulating bone marrow pluripotent stem and progenitor or precursor cells to produce large numbers of mature platelets, erythrocytes, lymphocytes, neutrophils, monocytes
A nurse is caring for several patients with disorders with inflammatory responses. Which patient conditions arise from hyperresponsive adaptive immunity? Select all that apply.
• Atherosclerosis • Bronchial asthma • Multiple sclerosis Explanation: The innate immune system initiates the inflammatory response, which is partially responsible for common pathophysiologic conditions including atherosclerosis, coronary artery disease, bronchial asthma, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus.
A client comes to the clinic and reports having a productive cough, fever and malaise for the past week. A diagnosis of bacterial pneumonia is established. Based on this diagnosis the nurse knows which features of the immune system have been activated. Select all that apply.
• Cell killing are activated • Compliment is activated • Immunologic memory will be retained Explanation: Features of adaptive immunity are dependent upon exposure (first: delayed, second: immediate d/t production antibodies); specific for each unique antigen due to microbe recognition; retention of immunologic memory that is more rapid and efficient with subsequent exposure; defense includes cell killing and tagging of antigen by antibody for removal; cellular components include T and B lymphocytes, macrophages, DCs, NK cells; and molecular components are antibodies, cytokines, complement system.
An infection control nurse is conducting research on the activation of the immune system and is identifying anatomical locations where primary immune responses are initiated. Which of the following locations should be included in the research study? Select all that apply.
• Lymph nodes • Spleen • Tonsils • Peyer patches Explanation: Chemokines are a subset of cytokines that consist of small protein molecules involved in both immune and inflammatory responses. They are responsible for directing leukocyte migration to areas of injury and to locations where primary immune responses are initiated such as lymph nodes, the spleen, Peyer patches, and the tonsils.
The effector responses of innate immunity include: Select all that apply.
• Phagocytosis • Viral destruction • Initiation of inflammatory response • Recruitment of the complement system Explanation: The effector responses of innate immunity involve viral destruction by natural killer (NK) cells, phagocytosis of microbes by neutrophils and monocytes, initiation of the inflammatory response, and recruitment of the complement system.
Which of the following characteristics correspond with innate immunity? Select all that apply.
• Similar immune response for each exposure • Immediate response to antigen invasion Explanation: Innate immunity is immediate, but it is limited to certain general classes of microbes instead of to specific organisms. The response to each infection is similar; some defenses are the epithelium of the skin and mucous membranes along with inflammation and fever. Cellular components of innate immunity include phagocytes, natural killer cells, and dendritic cells. Cytokines, complement proteins, acute-phase proteins, and soluble mediators are molecular components of the innate immunity.
A teenage client is exposed to a person infected with chicken pox. After two weeks, the client has not contracted the virus. How is this possible? Select all that apply.
• The client was previously exposed to chicken pox. • The client was vaccinated for chicken pox. Explanation: Active immunity is acquired when the host mounts an immune response to an antigen either through the process of vaccination or from environmental exposure. It is called active immunity because it requires the host's own immune system to develop an immunological response including the development of memory. Passive immunity transferred from mother to fetus only lasts a few weeks to months following birth.
A nurse is teaching a group of seniors about the decline of the immune system due to aging. Which of the following topics should be included in the teaching plan regarding the immune response of the elderly? Select all that apply.
• Weakened response to vaccinations • Increase in susceptibility to infections • Higher incidence of cancer Explanation: As we age, the ability of the immune system to protect the body from pathogenic organisms and environmental toxins declines as a result of an overall decline in immune responsiveness. This results from changes in both cell-mediated and humoral immune responses. As a result, older adults are more susceptible to infections, have more evidence of autoimmune and immune complex disorders, and have a higher incidence of cancer than do younger people. In addition, the immune system of older adults is less likely to respond appropriately to immunization. As a result, older adults have a weakened response to vaccination. Older adults also frequently have many comorbid conditions that impair normal immune function and compromise the immune response.