Question 1

Innate immunity?

Accepted Answer

Answer reason: Innate immunity is the body’s immediate, first-line defense and does not require prior exposure to a pathogen to respond. It relies on broad pattern recognition and includes physical/chemical barriers and rapid cellular responses (e.g., phagocytes, NK cells, complement), making it nonspecific. Immunologic memory and antigen-specific lymphocytes (T and B cells) are defining features of adaptive immunity, not innate defenses. Because it is protective, it decreases rather than increases susceptibility to disease.

Question 2

The lectin pathway for complement action is initiated by?

Accepted Answer

Answer reason: The lectin pathway is an innate immune mechanism triggered when host pattern-recognition molecules bind conserved carbohydrate patterns on pathogens. Mannose-binding lectin (MBL) specifically recognizes mannose-rich glycans on microbial surfaces and, via MASPs, activates complement leading to C3 convertase formation. Host cells are protected because their surface carbohydrates are typically capped/arranged in ways that reduce MBL binding, preventing inappropriate activation on self membranes. Options referencing gram-positive/negative cell walls are too nonspecific for lectin initiation, and “lectins of the microbe” reverses the direction of recognition (the host provides the lectin).

Question 3

Phagocytes utilize all of the following to optimize interaction with (getting to and getting hold of) microorganisms EXCEPT?

Accepted Answer

Answer reason: Phagocyte “getting to” microbes is driven by chemotaxis, and “getting hold of” them is enhanced by opsonization and complement (e.g., C3b) that increase binding and facilitate engulfment. Physical trapping against a rough surface can also aid contact between the phagocyte and the microorganism, improving the chance of attachment and ingestion. Lysozyme is an antimicrobial enzyme that breaks down peptidoglycan in bacterial cell walls, which helps kill bacteria but does not primarily function to direct migration or increase adherence for phagocytosis. Therefore it is the best exception among the listed mechanisms for optimizing interaction in terms of reaching and attaching to microbes.

Question 4

All of the following are effects of histamine EXCEPT?

Accepted Answer

Answer reason: Histamine is a key mediator of the innate inflammatory response released mainly from mast cells and basophils, producing vasodilation and increased capillary permeability that facilitates leukocyte recruitment to the site of injury. These vascular changes support containment and clearance of harmful stimuli by enabling phagocytes and plasma proteins to reach affected tissues, indirectly aiding removal and limiting spread. Subsequent phases of inflammation include cleanup and progression toward tissue repair via recruited cells and mediators, but antibody generation is not a direct effect of histamine. Antibody production is an adaptive immune function mediated by B lymphocytes/plasma cells rather than an immediate histamine-driven inflammatory mechanism.

Question 5

Each of the following is an effect of complement activation EXCEPT?

Accepted Answer

Answer reason: Complement activation primarily drives opsonization (C3b), inflammatory recruitment and vascular permeability (C3a/C5a anaphylatoxins), and direct microbial killing via the membrane attack complex (C5b-9). These mechanisms explain bacterial cell lysis, enhanced phagocytosis (through opsonization and chemotaxis), and increased blood vessel permeability. Interference with viral replication is instead a hallmark of type I interferons (e.g., IFN-α/β) produced in response to viral infection, not a direct complement effect. Therefore this option is the exception.

Question 6

Which of the following is an effect of opsonization?

Accepted Answer

Answer reason: g., IgG Fc region and C3b) to enhance recognition by phagocyte receptors. This coating improves binding between the phagocyte and the microbe, which accelerates and strengthens phagocytosis. Margination and diapedesis describe leukocyte movement to and through vessel walls during inflammation, not the tagging step that improves microbe binding. Cytolysis is classically complement membrane attack complex–mediated killing, which is a different downstream effector mechanism.

Question 7

Neutrophils with defective lysosomes are unable to?

Accepted Answer

Answer reason: Lysosomes (and their granule enzymes) are central to the intracellular killing phase of neutrophil function after phagocytosis, because they deliver microbicidal contents into the phagolysosome. If lysosomal function is defective, the neutrophil’s ability to generate and deploy effective intracellular toxic mediators for killing is impaired, leading to failure of effective microbial destruction despite intact recruitment. Chemotaxis, migration, and initial adherence are primarily governed by surface receptors, adhesion molecules, and inflammatory chemoattractants rather than lysosomal integrity. Engulfment (phagocytosis) can still occur, but killing of ingested organisms is the key step most compromised when lysosomal machinery is defective.

Question 8

The classical pathway for complement activation is initiated by?

Accepted Answer

Answer reason: The core principle is that the classical complement pathway is triggered when C1 binds to antibodies (IgM or IgG) that are already bound to antigen, forming immune complexes. This antibody-dependent activation distinguishes the classical pathway from the alternative and lectin pathways, which do not require antibodies. Options describing C5–C9 refer to the terminal membrane attack complex formed downstream after earlier complement activation steps. Lipid-carbohydrate complexes more closely align with nonclassical activation (e.g., lectin/alternative), and “factors released from phagocytes/damaged tissues” are inflammatory mediators rather than the initiating signal for the classical complement cascade.

Question 9

Several inherited deficiencies in the complement system occur in humans. Which of the following would be the MOST severe?

Accepted Answer

Answer reason: Loss of this component produces broad, profound impairment in bacterial clearance and markedly increases risk of severe, recurrent pyogenic infections and sepsis. In contrast, deficiencies of terminal components (C5–C8) primarily disrupt membrane attack complex formation, classically predisposing to Neisseria infections but leaving upstream opsonization largely intact. Because it cripples multiple pathways and the most important complement-mediated defense mechanisms, this deficiency is the most severe overall.

Question 10

Which of the following statements about fixed macrophages is FALSE?

Accepted Answer

Answer reason: Macrophages arise from the mononuclear lineage: bone marrow precursors develop into circulating monocytes, which then differentiate into macrophages within tissues. Fixed (resident) macrophages are long-lived tissue macrophages located in specific organs (e.g., Kupffer cells in liver, microglia in CNS) and are part of the mononuclear phagocyte system. Neutrophils are polymorphonuclear granulocytes with a distinct lineage and do not differentiate into monocytes/macrophages. At sites of infection, macrophages can accumulate via recruitment of monocytes and activation/expansion of resident macrophage populations, which supports the other statements as true.

Question 11

Margination refers to?

Accepted Answer

Answer reason: In acute inflammation, leukocytes first shift from the central blood flow toward the vessel periphery and then loosely attach to the endothelial surface, which is termed margination (and rolling). This step is driven by endothelial activation and adhesion molecule expression, positioning cells for subsequent firm adhesion and extravasation. By contrast, chemotaxis describes directed movement toward chemical gradients in tissue, and diapedesis refers to passage through the vessel wall. Adherence to microorganisms is later in the process (opsonization/attachment) after leukocytes have reached the site of infection.

Question 12

Which of the following statements is TRUE?

Accepted Answer

Answer reason: Complement is an innate immune cascade made up of many plasma proteins that circulate largely as inactive zymogens until triggered. Standard immunology describes over 30 complement components and regulators, so stating there are at least thirty is accurate. The proteins are not constantly active in serum because uncontrolled activation would damage host tissues and is prevented by regulatory factors. Cytolysis is mediated by the membrane attack complex (C5b-9), whereas factors B, D, and P mainly amplify the alternative pathway rather than directly forming the lytic complex.

Question 13

The nurse is providing preoperative teaching for a client scheduled to receive a porcine heart valve replacement. The nurse determines that the client has an understanding of the type of replacement he will receive when the client describes the replacement as what?

Accepted Answer

Answer reason: This concept contrasts with allogeneic (same species, different individual), autologous (self), and syngeneic (genetically identical donor such as an identical twin). Recognizing the graft type helps anticipate relative immune compatibility and the need for specific follow-up considerations. Among the options, only this one correctly denotes a cross-species transplant material.

Question 14

Serological testing is based on the fact that?

Accepted Answer

Answer reason: Serologic tests rely on the specific binding between an antibody and its corresponding antigen, enabling identification of pathogens or immune responses. This specificity is what allows assays like agglutination, ELISA, and immunofluorescence to detect a particular target rather than reacting broadly. Option C is too general because antibody production can occur against many antigens (not only bacteria) and does not explain the testing principle. Options A, D, and E are incorrect because antigens differ among organisms, antibodies do not create antigens, and agglutination requires matching antibodies rather than “any” antibodies.

Question 15

All of the following are true regarding NK cells EXCEPT?

Accepted Answer

Answer reason: NK cells are innate lymphocytes that eliminate stressed, virus-infected, and malignant cells primarily through cytotoxic killing rather than engulfment. They induce target-cell death by releasing perforin and granzymes and by triggering apoptosis pathways (e.g., via death receptors), which fits their role in nonspecific defense. Phagocytosis is a function of professional phagocytes such as neutrophils and macrophages, not NK cells. The other statements align with NK cell biology: they are lymphocytes, present in lymphoid tissues and circulation, and can kill infected and some tumor cells using cytotoxic mediators.

Question 16

All of the following are part of the mechanism of action of alpha and beta interferons EXCEPT?

Accepted Answer

Answer reason: Type I interferons (alpha and beta) act by binding receptors on nearby uninfected cells and triggering intracellular signaling that turns on interferon-stimulated genes. This leads to production of antiviral proteins that inhibit translation and degrade viral RNA, thereby interrupting multiple steps of viral replication. The effect is typically short-lived and must be continually induced; it is not characterized by prolonged effectiveness over long periods. By contrast, inducing gene transcription is a key part of the interferon response pathway after receptor activation.

Question 17

The nurse is caring for a child with perinatally acquired human immunodeficiency virus. The nurse is aware that children usually demonstrate symptoms of acquired immunodeficiency syndrome (AIDS) at what age?

Accepted Answer

Answer reason: Early infancy may be relatively asymptomatic because passive maternal IgG and variable early viral control can mask overt disease. By the second year of life, recurrent/opportunistic infections, failure to thrive, and persistent lymphadenopathy are more likely to become clinically apparent if untreated. Much later onset (preschool years) is less typical for perinatal infection compared with symptom development in the first 1–2 years.

Question 18

A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?

Accepted Answer

Answer reason: Neutrophils and later macrophages migrate to the wound via chemotaxis and eliminate invading bacteria through phagocytosis and intracellular killing. Several other options are surface or site-specific barriers (e.g., respiratory clearance) that do not address microbes that have entered a deep tissue cut. Therefore, the key mechanism that actively clears contaminating microbes in this scenario is cellular phagocytosis during inflammation.

Question 19

The nurse is attending the annual neighborhood picnic. A neighbor tells the nurse that a friend was recently diagnosed with systemic lupus erythematosus (SLE) and she is afraid she will contract it. Which of the following clients is most at risk for SLE?

Accepted Answer

Answer reason: A young adult woman therefore carries substantially higher baseline risk than men or older adults. While Black race increases risk, incidence peaks in reproductive years, making the younger woman more at risk than an elderly woman. This also supports patient education that SLE is not contagious and cannot be “caught” through contact.

Question 20

All of the following pertain to fever EXCEPT that it?

Accepted Answer

Answer reason: Fever is an innate defense response that tends to inhibit microbial replication, in part by decreasing available iron (via sequestration and reduced serum iron), which deprives pathogens of an essential growth factor. Endogenous pyrogens such as IL-1 and TNF-α act at the hypothalamus to raise the thermoregulatory set point, producing fever. Elevated temperature can enhance certain immune functions, including T-lymphocyte activity, and can augment the effectiveness of interferon-mediated antiviral responses. Therefore, the statement claiming fever increases iron absorption and thereby accelerates microbial growth contradicts the known protective physiologic effects of fever.

Question 21

Which of the following statements about the classical pathway of complement activation is FALSE?

Accepted Answer

Answer reason: The classical complement pathway converges on activation of C3 via the C4b2a C3 convertase, making C3 central rather than absent. Once cleaved, C3 generates C3a (anaphylatoxin promoting inflammation) and C3b (major opsonin), which are hallmark downstream effects of classical activation. By contrast, initiation of the classical pathway is correctly triggered when C1 binds to antigen–antibody (IgG/IgM) complexes, and C1 is the first component engaged. Therefore, stating that C3 is not involved contradicts the required core step shared by classical complement activation.

Question 22

A nurse has volunteered for a mission trip to an area with a high incidence of HIV. Part of the responsibility will be teaching a class about HIV. The next question in the PowerPoint presentation is, “Which body substances most easily transmit human immunodeficiency virus (HIV)?” Which of the following options would you include in your next PowerPoint slide to answer that question?

Accepted Answer

Answer reason: These include blood and semen, which are well-established major transmission vehicles via needlestick exposure, transfusion (rare with screening), and sexual contact. Saliva, feces, tears, and urine are not considered effective transmission fluids in typical exposures because viral levels are negligible and inhibitory factors reduce infectivity. Breast milk can transmit HIV, but paired with tears in the options it is less correct than the pairing of two high-risk fluids.

Question 23

A 27-year-old male who is an established client in the in the Family Medicine Clinic was recently diagnosed with acquired immunodeficiency syndrome (AIDS). When reviewing his chart, what does the nurse expect to find with this diagnosis?

Accepted Answer

Answer reason: This option directly reflects the required HIV infection plus the key laboratory threshold that marks progression to AIDS. Opportunistic infections like tuberculosis or CMV can occur but are not required for the diagnosis, making that choice too specific. The option referencing “alternative lifestyle” is not diagnostic and is clinically inappropriate, and the option pairing CD4+

Question 24

The nurse is discussing the underlying mechanism of psoriasis with a client recently diagnosed with the condition. The nurse explains that psoriasis is primarily associated with?

Accepted Answer

Answer reason:  Psoriasis is an immune-mediated inflammatory disease driven largely by T-cell activation and cytokines (e.g., TNF-α, IL-17/IL-23) that accelerate keratinocyte proliferation and cause thick, scaly plaques. An overactive immune response misdirected toward skin structures best explains the chronic inflammation and epidermal hyperproliferation. A deficiency of T lymphocytes would more typically reduce immune responses and predispose to infection rather than create the characteristic inflammatory plaques. Melanocyte dysfunction aligns more with pigment disorders (e.g., vitiligo), and excessive sebum with follicular plugging describes acne pathogenesis, not psoriasis.

Question 25

Only immunoglobulin which can cross the placenta is?

Accepted Answer

Answer reason: This provides the fetus/newborn with passive systemic immunity, especially in late pregnancy when transfer increases. IgM is a large pentamer and does not cross the placenta, so fetal IgM suggests in utero infection rather than maternal transfer. IgA is primarily secretory (e.g., in breast milk) and IgE is not significantly transported across the placenta for passive protection.

Question 26

Which type of immunity is acquired through vaccination?

Accepted Answer

Answer reason: Vaccination works by exposing the immune system to an antigen (or antigenic components) so the body mounts its own adaptive immune response. This leads to clonal expansion of B and T lymphocytes and development of immunologic memory, providing longer-lasting protection. Passive immunity instead involves transfer of preformed antibodies (e.g., immunoglobulin, maternal IgG) and does not create memory. Innate immunity is inborn and non-specific, and herd immunity is a population-level effect rather than an individual immune mechanism.

Question 27

What is the body’s ability to protect itself against harmful invading agents such as bacteria, toxins, viruses, and foreign bodies called?

Accepted Answer

Answer reason: It includes innate defenses (barriers, phagocytes, complement) and adaptive responses (B- and T-lymphocytes with specificity and memory) that together provide protection from infection and invasion. Inflammation is an important component of the innate immune response, but it is a process/sign rather than the broad, encompassing protective ability being asked. Hormones and glands relate to endocrine regulation and do not primarily describe defense against invading agents.

Question 28

Herd immunity is best achieved by?

Accepted Answer

Answer reason: Immunization achieves this safely by inducing adaptive immunity in many people without requiring widespread infection. Isolation and quarantine reduce exposure temporarily but do not create lasting immunity in the community. Screening helps identify cases but does not by itself increase immune individuals or sustain reduced transmission over time.

Question 29

Vaccine is an example of...?

Accepted Answer

Answer reason: This antigen exposure leads to activation of B and T lymphocytes and development of immunologic memory, enabling a faster, stronger response on future exposure. An antibody would represent passive immunity when administered directly (e.g., immunoglobulin), not the usual mechanism of vaccination. Antibiotics treat bacterial infections and do not induce immune memory, and hormones are unrelated to immune priming.

Question 30

MR vaccine prevents?

Accepted Answer

Answer reason: This pairing is distinct from MMR, which additionally includes mumps. Polio prevention is provided by IPV/OPV formulations, not MR. Therefore the option matching the MR components is the correct choice.

Question 31

HIV mainly attacks – cells ?

Accepted Answer

Answer reason: Progressive infection and depletion/dysfunction of CD4+ T helper lymphocytes undermines cell-mediated immunity and predisposes to opportunistic infections and malignancies. RBCs lack nuclei and do not express CD4, so they are not a meaningful reservoir for viral replication. Platelets and neurons may be affected indirectly or via other mechanisms, but they are not the primary cell type HIV mainly attacks in standard pathogenesis.

Question 32

White blood cells function mainly in –?

Accepted Answer

Answer reason: White blood cells are the primary cellular components of the immune system and are responsible for recognizing, attacking, and coordinating responses against pathogens and abnormal cells. Different WBC types (e.g., neutrophils, lymphocytes, monocytes) perform phagocytosis, antibody-mediated defense, and immune regulation. Digestion and respiration are not core functions of circulating leukocytes, and clotting is mainly mediated by platelets and coagulation factors rather than WBCs. Therefore, the main function being tested is host defense.

Question 33

Severe allergic swelling is called —?

Accepted Answer

Answer reason: This term specifically denotes severe, localized allergic swelling and is clinically important because it can compromise the airway. “Edema” is a broad term for fluid accumulation and does not specifically indicate an allergic mechanism or the typical distribution. Cyanosis and vertigo are unrelated findings (hypoxemia-related discoloration and dizziness, respectively), not types of swelling.

Question 34

Hepatitis B vaccine is —?

Accepted Answer

Answer reason: This is the defining feature of a subunit (recombinant) vaccine: it contains only specific antigenic components rather than intact organisms. That design improves safety in immunocompromised patients compared with live-attenuated products. It is not a toxoid because the target pathogen’s disease is not mediated primarily by an exotoxin requiring detoxified toxin for immunity. It is also not a whole inactivated-virus preparation, since the vaccine antigen is produced via recombinant technology and purified as a surface protein component.

Question 35

Which of the following can induce delayed hypersensitivity reaction?

Accepted Answer

Answer reason: Contact sensitizers (often acting as haptens) trigger antigen-specific T cells in the skin, producing allergic contact dermatitis as a classic delayed reaction. By contrast, anaphylaxis is an immediate type I (IgE-mediated) response, and many acute transfusion reactions are antibody/complement mediated (type II/III) rather than delayed type IV. Bacterial septicemia reflects infection-driven systemic inflammation, not a hypersensitivity mechanism.

Question 36

Meningitis occurs as an extension of a variety of bacterial infections due to which of the following conditions?

Accepted Answer

Answer reason: g., nasopharynx, otitis media, sinusitis) or during bacteremia, allowing invasion of the meninges. Reduced or absent effective acquired immunity (such as lack of protective antibodies, inadequate opsonization, or impaired complement function) increases susceptibility to multiple bacterial pathogens that can extend to the CNS. This best explains why meningitis can be an extension of a variety of bacterial infections rather than being tied to a single structural defect. Anatomic abnormalities can predispose to recurrent meningitis but do not broadly account for extension from many common bacterial infections in the general case.

Question 37

The reason the AIDS virus is so devastating to the immune system is that it attacks?

Accepted Answer

Answer reason: HIV’s key pathogenic mechanism is infection and progressive depletion/dysfunction of CD4+ T-helper cells, which coordinate both cell-mediated and humoral immune responses. Loss of CD4 help impairs activation of macrophages and CD8 cytotoxic T cells and reduces B-cell class switching and effective antibody responses, leading to broad susceptibility to opportunistic infections and certain malignancies. This upstream “central node” failure makes the immune collapse more profound than targeting a single effector cell type. By contrast, isolated CD8 or neutrophil impairment would not explain the characteristic combined immunodeficiency pattern seen in AIDS.

Question 38

What client presentation is one that is experiencing a type IV reaction?

Accepted Answer

Answer reason: Urushiol from poison ivy triggers this classic delayed eczematous rash via sensitized T lymphocytes and cytokine-driven inflammation. In contrast, latex hypersensitivity is most commonly an immediate IgE-mediated type I reaction with urticaria, rhinitis, or anaphylaxis. Thrombocytopenic purpura and systemic lupus erythematosus are more consistent with antibody/immune-complex mechanisms (type II/III) rather than a delayed-type reaction.

Question 39

AIDS is a disease of?

Accepted Answer

Answer reason: The defining clinical problem is immunodeficiency, leading to opportunistic infections and certain malignancies that occur when immune defenses are impaired. The lungs, skin, and liver can be affected by opportunistic diseases or complications, but they are not the primary system that is fundamentally damaged. Therefore, the best classification is a disease of the immune system.

Question 40

What type of hypersensitivity reaction is exhibited by a client that has been diagnosed with rheumatoid arthritis?

Accepted Answer

Answer reason: These circulating complexes can deposit in synovial tissue, activate complement, and recruit neutrophils and macrophages, driving chronic synovitis and joint destruction. That mechanism is the defining feature of type III (immune complex–mediated) hypersensitivity. A common distractor is type IV, which is T-cell mediated and classically linked to delayed reactions like contact dermatitis and TB skin testing rather than immune-complex deposition as the central mechanism here.

Question 41

A newborn infant of a mother who has human immunodeficiency virus (HIV) infection is tested for the presence of HIV antibodies. An enzyme-linked immunosorbent assay (ELISA) is performed, and the results are positive. Which is the correct interpretation of these results?

Accepted Answer

Answer reason: Therefore a positive HIV antibody test in a newborn of an HIV-positive mother most commonly reflects passively transferred maternal antibodies rather than true neonatal infection. Confirmation of infant infection requires virologic testing (e.g., HIV PCR/RNA) rather than antibody-based screening. The options implying the newborn is definitively HIV-positive or will develop AIDS confuse antibody presence with proven infection and disease progression.

Question 42

Immunoglobulin that can cross the placental barrier and reach the fetal circulation is?

Accepted Answer

Answer reason: Among immunoglobulin classes, only IgG efficiently binds these receptors and crosses the placenta in clinically meaningful amounts, especially in the third trimester. IgM is a large pentamer and does not cross the placenta; its presence in a newborn suggests fetal (not maternal) production during intrauterine infection. IgA is primarily secretory/mucosal and is transferred mainly through breast milk rather than across the placenta.

Question 43

A client who received a skin graft 2 months ago because of extensive burns, reports to the clinic reporting redness, swelling, fever, and tenderness over the graft site. The nurse interprets that this client is exhibiting which of the following?

Accepted Answer

Answer reason: The timing at 2 months plus classic inflammation over the graft site aligns with this pattern. Hyperacute rejection occurs within minutes to hours due to preformed antibodies, making it incompatible with a 2-month onset. Chronic rejection develops over months to years and is characterized more by progressive fibrosis and loss of graft function rather than prominent acute inflammatory signs, and graft-versus-host disease is primarily associated with hematopoietic stem cell transplantation rather than a skin graft scenario.

Question 44

Hay fever is a sign of which of the following?

Accepted Answer

Answer reason: The clinical pattern classically includes sneezing, rhinorrhea, nasal congestion, and itchy/watery eyes, which is most consistent with an allergic mechanism. Old age, malnutrition, and overwork do not specifically cause this immune-triggered inflammatory response pattern. A common confusion is with infectious rhinitis, but hay fever is defined by allergen exposure and atopic features rather than fever from infection.

Question 45

Which of the following clinical manifestations of the aging immune system should alert the nurse to increased susceptibility to illness in elderly clients?

Accepted Answer

Answer reason: This dysregulation can manifest as increased autoimmune activity while simultaneously reducing effective responses to new antigens, contributing to higher infection risk in older adults. Reduced thymic function and impaired B-cell quality lead to weaker cell-mediated immunity and less effective antibody responses, even if some immune activity appears heightened. The other options describe increases in immune cell production, lymphoid tissue, or lymphocyte circulation, which would generally suggest improved immune capacity rather than increased susceptibility.

Question 46

What statement made by the student best explains type II reaction, as with a hemolytic blood transfusion?

Accepted Answer

Answer reason: " Type II hypersensitivity is antibody-mediated cytotoxicity in which IgG or IgM binds to antigens on cell surfaces, activating complement and causing cell destruction, as in acute hemolytic transfusion reactions. In this setting, antibodies target antigens on transfused RBC membranes, leading to rapid intravascular hemolysis. The immune-complex mechanism described in one option corresponds to type III hypersensitivity, not type II. The sensitized T-cell delayed response describes type IV hypersensitivity.

Question 47

The first antibody produced after an infection is?

Accepted Answer

Answer reason: IgM appears first in serum because it is produced rapidly and does not require prior affinity maturation, making it a key marker of recent or acute infection. Over time, helper T-cell signaling drives switching to IgG, which predominates later and provides longer-term systemic protection. IgE is primarily associated with allergic responses and parasitic infections rather than being the first general antibody after typical infection.

Question 48

The Largest Lymphatic Organ Is ...?

Accepted Answer

Answer reason: The spleen is the largest lymphatic (lymphoid) organ and functions as a major site for immune surveillance and response to blood-borne pathogens. It filters blood, removes aged or abnormal erythrocytes and platelets, and mounts adaptive immune responses via white pulp lymphoid tissue. Lymph nodes are numerous and important but each is much smaller and they primarily filter lymph rather than blood. The liver and pancreas have critical metabolic and digestive/endocrine roles, but they are not classified as the largest lymphatic organ.

Question 49

Antibodies are produced by ...?

Accepted Answer

Answer reason: B lymphocytes are a type of white blood cell responsible for humoral immunity, so this option best captures the producing cell lineage. Red blood cells primarily transport oxygen and lack the machinery for antibody synthesis. Platelets function mainly in hemostasis, and plasma is the fluid component that carries antibodies rather than producing them.

Question 50

The nurse is examining a patient at an internal medicine clinic. Which of the following clinical manifestations would support a diagnosis of systemic lupus erythematosus (SLE)?

Accepted Answer

Answer reason: A malar (“butterfly”) rash plus fever and fatigue fits classic inflammatory/autoimmune presentation. Proteinuria specifically supports renal involvement (lupus nephritis), a key systemic feature that strengthens the diagnosis beyond isolated skin symptoms. Diarrhea is not a typical hallmark manifestation of SLE, and hypothermia or weight gain are nonspecific and less supportive than evidence of renal disease.

Train with a large NCLEX question bank and jump into a full exam-style simulator

Immunology NCLEX Practice Test

Continue Learning