Question 1

The largest lymphoid tissue is?

Accepted Answer

Answer reason: The spleen is the largest secondary lymphoid organ, responsible for filtering blood and mounting immune responses.

Question 2

The x-interferons are primarily ____________?

Accepted Answer

Answer reason: Alpha (x) interferons are produced mainly by leukocytes, hence termed leukocytic interferons; beta interferons are produced by fibroblasts. Therefore both 'leukocytes' and 'leukocytic' describe x-interferons.

Question 3

What is the major immunoglobulin found in serum?

Accepted Answer

Answer reason: IgG is the most abundant immunoglobulin in serum, comprising the majority of circulating antibodies; IgA predominates in mucosal secretions, and IgM is produced early in primary responses.

Question 4

What is the first line of defense against microorganisms?

Accepted Answer

Answer reason: The first line of defense in innate immunity is the physical barrier of the skin and mucous membranes, which prevent pathogen entry. Neutrophils, monocytes, and complement act after barriers are breached.

Question 5

Which class of antibody is associated with an allergic reaction?

Accepted Answer

Answer reason: IgE mediates type I hypersensitivity by binding to mast cells and basophils, triggering allergic reactions.

Question 6

Which immunoglobulin crosses the placental barrier?

Accepted Answer

Answer reason: Only IgG crosses the placenta. IgA is mainly in mucosal secretions and colostrum, and IgM is too large to cross. Since IgG is not an option, none of the listed choices cross the placental barrier.

Question 7

Which immunoglobulin is found in human milk, especially colostrum, vaginal secretions, and tears?

Accepted Answer

Answer reason: Secretory IgA predominates in mucosal secretions such as breast milk (especially colostrum), tears, saliva, and vaginal secretions, providing mucosal immunity.

Question 8

Colostrum is rich in?

Accepted Answer

Answer reason: Colostrum contains high levels of secretory IgA, which provides mucosal immunity to the newborn.

Question 9

Macrophages present in the liver are called?

Accepted Answer

Answer reason: Liver-resident macrophages are Kupffer cells. Mesangial cells are in the renal glomeruli; microglia are CNS macrophages, and chondrocytes are cartilage cells.

Question 10

Herd immunity is useful in preventing which disease?

Accepted Answer

Answer reason: Herd immunity reduces person-to-person transmission; it is highly effective for human-only transmissions like poliovirus. It is not useful for tetanus (not transmitted person-to-person) and is limited for tuberculosis.

Question 11

Who invented the smallpox vaccine?

Accepted Answer

Answer reason: Edward Jenner developed the first successful smallpox vaccine in 1796 using material from cowpox lesions.

Question 12

Enzyme, heparin, and histamine are secreted by?

Accepted Answer

Answer reason: Mast cells are tissue-resident immune cells whose granules contain histamine and heparin; degranulation releases these mediators.

Question 13

An allergy involves?

Accepted Answer

Answer reason: Type I hypersensitivity (allergic reactions) is mediated by IgE bound to mast cells and basophils, leading to histamine release upon allergen exposure.

Question 14

A patient is seen in the emergency department after a bee sting caused bronchospasm and severe pruritus. The nurse understands that this type of hypersensitivity reaction is known as?

Accepted Answer

Answer reason: Bee stings triggering bronchospasm and severe itching indicate an acute anaphylactic reaction, which is IgE-mediated immediate hypersensitivity—Type I.

Question 15

What is antiserum?

Accepted Answer

Answer reason: Antiserum is serum that contains high titers of antibodies directed against a specific antigen, used for passive immunization. Therefore it contains specific antibodies, not antigens.

Question 16

Glomerulonephritis is due to?

Accepted Answer

Answer reason: Most glomerulonephritis, such as post-streptococcal GN, results from type III hypersensitivity where circulating immune complexes deposit in glomeruli and activate complement.

Question 17

Tonsils functions are?

Accepted Answer

Answer reason: Tonsils are lymphoid tissue that trap pathogens entering via the nose and mouth and mount immune responses, helping block entry and destroy germs. They do not form RBCs, so both B and C are correct.

Question 18

Anaphylaxis is type ... hypersensitivity reaction?

Accepted Answer

Answer reason: Anaphylaxis is an immediate IgE-mediated reaction, which is Type I hypersensitivity.

Question 19

B and T cells spend most of their time in the _______?

Accepted Answer

Answer reason: B and T lymphocytes predominantly reside and recirculate through lymphoid tissues and the lymphatic system (lymph nodes, spleen, MALT), not mainly in the bloodstream or heart/capillaries.

Question 20

Graft from identical twin is?

Accepted Answer

Answer reason: A graft between genetically identical individuals (identical twins) is an isograft. Autograft is self-to-self, allograft is same species non-identical, and xenograft is between different species.

Question 21

Why is immunosuppressive therapy effective for a client with myasthenia gravis?

Accepted Answer

Answer reason: Myasthenia gravis is an autoimmune disease where antibodies target acetylcholine receptors. Immunosuppressive therapy reduces production of these autoantibodies, improving neuromuscular transmission. Option D describes acetylcholinesterase inhibitors, not immunosuppressants.

Question 22

What is the most likely diagnosis for a client 19 days post-autologous peripheral blood stem-cell transplantation for non-Hodgkin’s lymphoma who presents with the illustrated skin changes?

Accepted Answer

Answer reason: Rash appearing about 2–8 weeks after stem-cell transplantation is most consistent with acute GVHD. Herpes zoster is dermatomal and usually occurs later; PICC infection is localized at the line site; a drug allergy is less likely given the post-transplant timing and context.

Question 23

The primary target cell of HIV is?

Accepted Answer

Answer reason: HIV binds the CD4 receptor with co-receptors (CCR5/CXCR4), making CD4+ helper its primary targets; RBCs and platelets lack nuclei and melanocytes are not targets.

Question 24

Which of the following cannot be prevented by immunization?

Accepted Answer

Answer reason: Vaccines exist for polio (OPV/IPV), tuberculosis (BCG), and cholera (oral vaccines). There is no approved vaccine to prevent onchocerciasis; control relies on ivermectin mass drug administration and vector control.

Question 25

What is the function of white blood cells?

Accepted Answer

Answer reason: White blood cells protect the body against pathogens through immune responses; red blood cells transport oxygen, platelets mediate clotting, and nutrient absorption is a gastrointestinal function.

Question 26

A positive tuberculin test is an example of which type of hypersensitivity?

Accepted Answer

Answer reason: The tuberculin skin test elicits a delayed-type (cell-mediated) hypersensitivity reaction mediated by T helper 1 cells and macrophages, which is Type IV.

Question 27

Which type of hypersensitivity reaction is associated with Rh incompatibility (Hemolytic disease of the newborn)?

Accepted Answer

Answer reason: Rh incompatibility involves maternal anti-D IgG antibodies that cross the placenta and cause complement-mediated cytotoxic hemolysis of fetal RBCs, which is a type II (antibody-mediated) hypersensitivity.

Question 28

What are antigens?

Accepted Answer

Answer reason: An antigen is any substance recognized by the immune system that elicits an immune response, particularly the production of specific antibodies.

Question 29

Which of the following is a serious condition, which weakens the body’s immune system, leaving it unable to fight off illness?

Accepted Answer

Answer reason: AIDS, caused by HIV, destroys CD4+ T lymphocytes leading to immunodeficiency and inability to fight infections.

Question 30

Combat the effects of histamine in allergic reactions, phagocytize antigen–antibody complexes, and destroy certain parasitic worms are the functions of?

Accepted Answer

Answer reason: The described functions are characteristic of eosinophils (neutralize histamine, ingest immune complexes, kill helminths). That option is absent; among the listed choices, the only immune leukocyte is lymphocytes, so B is the closest, though the item appears flawed.

Question 31

Which of the following best describes the human body's defense mechanism against environmental bacteria?

Accepted Answer

Answer reason: Mucous membranes provide a broad innate barrier against environmental bacteria by trapping pathogens and containing antimicrobial substances. Hair in the nose, saliva, and tears offer localized protection, and osteoblasts are unrelated to immune defense.

Question 32

Which of the following is the lymphoid organ that is a reservoir for red blood cells and filters organisms from the blood?

Accepted Answer

Answer reason: The spleen is a secondary lymphoid organ that filters blood to remove pathogens and senescent erythrocytes and serves as a reservoir for red blood cells and platelets.

Question 33

Humoral immunity is associated with which type of cell?

Accepted Answer

Answer reason: Humoral immunity is antibody-mediated and is produced by B lymphocytes that differentiate into plasma cells; T cells mediate cell-mediated immunity.

Question 34

Which cell type is responsible for producing antibodies?

Accepted Answer

Answer reason: Antibodies are produced by B lymphocytes that differentiate into plasma cells; neutrophils, eosinophils, and monocytes do not secrete antibodies.

Question 35

What is an injection consisting of bacterial cells that have been modified called?

Accepted Answer

Answer reason: Modified or inactivated bacterial cells used to induce active immunity constitute a vaccine. Antitoxin is antibody therapy; toxin is the harmful substance; toxoid is a modified toxin, not cells.

Question 36

The protective effects of breast milk are associated with which of the following?

Accepted Answer

Answer reason: Breast milk is rich in secretory IgA, which coats infant mucosal surfaces and neutralizes pathogens, providing passive mucosal immunity. IgM is minimal, mast cells are not a milk component, and lysozyme is present but not the primary immunologic factor.

Question 37

Which disease listed is characterized by immunity that is not long lasting?

Accepted Answer

Answer reason: Immunity to influenza is short-lived and strain-specific due to frequent antigenic drift, so protection wanes and yearly vaccination is needed. Mumps generally confers long-lasting immunity; diphtheria and pertussis require boosters but are longer-lasting than influenza.

Question 38

Which statement is true regarding the infant's susceptibility to pertussis?

Accepted Answer

Answer reason: Infants do not receive reliable passive immunity to pertussis and are at highest risk early in life; maternal disease does not confer protective passive immunity, and newborns are not immune.

Question 39

Transplantation between members with the same genetic constitution is known as?

Accepted Answer

Answer reason: An isograft is a transplant between genetically identical individuals (e.g., monozygotic twins). Autograft is within the same person, allograft is between different individuals of the same species, and xenograft is between different species.

Question 40

Anti-rabies vaccine is made from which type of viruses?

Accepted Answer

Answer reason: Human rabies vaccines (e.g., HDCV, PCECV) are inactivated preparations; live attenuated rabies vaccines are not used for humans due to safety concerns.

Question 41

What is the third line of defense against micro-organisms?

Accepted Answer

Answer reason: The third line of defense is the adaptive immune response mediated by lymphocytes (B and T cells). Skin is first line; phagocytes and complement are part of the innate second line.

Question 42

Which immunoglobulin is primarily involved in allergic reactions?

Accepted Answer

Answer reason: IgE binds to mast cells and basophils and mediates type I hypersensitivity reactions, driving allergic responses via histamine release.

Question 43

Vaccination is an example of which type of immunity?

Accepted Answer

Answer reason: Vaccines introduce antigen to stimulate the person’s own immune system to produce antibodies and memory cells; this is active immunity induced by artificial means.

Question 44

Which immunoglobulin protects the surface of mucous membranes against bacteria, viruses, and other microorganisms?

Accepted Answer

Answer reason: IgA is the predominant immunoglobulin in mucosal secretions (tears, saliva, respiratory and GI secretions) and provides first-line defense by neutralizing pathogens on mucous membranes.

Question 45

What type of vaccine is the Hepatitis-B vaccine?

Accepted Answer

Answer reason: Hepatitis B vaccine is not live, not a toxoid, and not antisera; it is an inactivated (non-live) preparation. Among the given choices, the best match is killed vaccine.

Question 46

What is the second line of defense against microbes?

Accepted Answer

Answer reason: The second line of innate defense includes internal nonspecific responses such as phagocytosis by neutrophils and macrophages. Skin and mucous membranes are first-line barriers; B and T lymphocytes are third-line (adaptive) defenses.

Question 47

Maturation of T-cell lymphocytes takes place at which organ?

Accepted Answer

Answer reason: T lymphocytes undergo maturation and selection in the thymus, where they develop immunocompetence via positive and negative selection.

Question 48

Ms. X is diagnosed with acquired immunodeficiency syndrome (AIDS). The nurse caring for this patient is aware that for a patient to be diagnosed with HIV she should have which condition?

Accepted Answer

Answer reason: AIDS is diagnosed in an HIV-infected person when the CD4 T-cell count falls below 200 cells/microliter or an AIDS-defining illness occurs. Option D matches this criterion; the other options list higher CD4 counts or unrelated coinfections.

Question 49

Which of the following is used for passive immunization?

Accepted Answer

Answer reason: Passive immunization provides preformed antibodies via immune globulins or antisera, which come from human or animal sera. Vaccines and toxoids stimulate active immunity.

Question 50

What is the half-life of IgE?

Accepted Answer

Answer reason: IgE has a short serum half-life of approximately 2–3 days, whereas other immunoglobulins like IgG persist much longer.

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