Nokea
Which of the following leukocytes is involved in antibody-dependent cell-mediated cytotoxicity?
- A. Natural Killer (NK) cells
- B. Neutrophils
- C. Macrophages
- D. Mast cells
Correct Answer: A
Rationale: The correct answer is A: Natural Killer (NK) cells. NK cells are involved in antibody-dependent cell-mediated cytotoxicity by recognizing target cells coated with antibodies and inducing their death. NK cells play a crucial role in immune surveillance and defense against infected or malignant cells. Neutrophils, macrophages, and mast cells are not directly involved in antibody-dependent cell-mediated cytotoxicity. Neutrophils are primarily responsible for phagocytosis, macrophages are antigen-presenting cells, and mast cells are involved in allergic reactions.
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In a patient with leukocytosis with a shift to the left, what does the nurse recognize as causing this finding?
- A. The complement system has been activated to enhance phagocytosis.
- B. Monocytes are released into the blood in larger-than-normal amounts.
- C. The response to cellular injury is not adequate to remove damaged tissue and promote healing.
- D. The demand for neutrophils causes the release of immature neutrophils from the bone marrow.
Correct Answer: D
Rationale: A 'shift to the left' refers to an increase in immature neutrophils in circulation, which occurs when there is a high demand for neutrophils due to infection or inflammation. This phenomenon indicates that the bone marrow is releasing immature neutrophils to meet the body's needs.
Which of the following sentences is NOT true about type I hypersensitivity reactions?
- A. Symptoms manifest in allergic individuals only after a second encounter with an allergen
- B. Food allergies can result in systemic anaphylaxis
- C. TH2 lymphocytes are involved in their development
- D. They can be classified as genetic disorders because they are caused by a single gene defect
Correct Answer: D
Rationale: Step 1: Type I hypersensitivity reactions are immediate allergic reactions that occur upon initial exposure to an allergen, not just after a second encounter.
Step 2: Food allergies can lead to systemic anaphylaxis due to the rapid release of mediators like histamine.
Step 3: TH2 lymphocytes play a crucial role in the development of type I hypersensitivity reactions by promoting IgE production.
Step 4: Type I hypersensitivity reactions are not generally classified as genetic disorders since they result from an immune response to allergens, not a single gene defect.
Factors important in the eradication of smallpox include
- A. Smallpox is a human pathogen; it is not found in animals.
- B. The vaccine was easily delivered and did not require sophisticated materials or technical skills
- C. The disease is contagious only when the symptoms are manifest making isolation an effective measure
- D. All of the above is correct
Correct Answer: D
Rationale: The correct answer is D because all the factors mentioned are important in the eradication of smallpox. A is correct because smallpox is specific to humans, simplifying eradication efforts. B is correct as the vaccine was easily deployable. C is correct as isolation of symptomatic individuals helped control the spread. Therefore, all choices are important in the successful eradication of smallpox.
What did Paul Ehrlich predict in immunology?
- A. Existence of antibodies and their ability to bind toxins
- B. Discovery of germ theory
- C. Smallpox eradication
- D. Development of vaccines
Correct Answer: A
Rationale: Paul Ehrlich predicted the existence of antibodies and their ability to bind toxins. He introduced the concept of the side-chain theory, proposing that cells have specific receptors (later known as antibodies) that can bind to toxins and neutralize them. This groundbreaking idea laid the foundation for modern immunology. Ehrlich's work was instrumental in understanding the immune response and paved the way for advancements in vaccine development and disease treatment.
Choice B (Discovery of germ theory) is incorrect because it was proposed by Louis Pasteur and Robert Koch, not Paul Ehrlich. Choice C (Smallpox eradication) is incorrect as Ehrlich did not predict smallpox eradication. Choice D (Development of vaccines) is incorrect because while Ehrlich's work contributed to vaccine development, his specific prediction was about antibodies and their toxin-binding ability, not vaccines in general.
The HIV protein that allows fusion of the viral envelope with the cell plasma membrane is
- A. gp120
- B. gp41
- C. gp160
- D. CXCR4
Correct Answer: B
Rationale: The correct answer is B: gp41. Gp41 is responsible for the fusion of the viral envelope with the cell plasma membrane by undergoing conformational changes that allow the viral and cellular membranes to merge. Gp120 attaches to the host cell receptor (CD4), facilitating the binding of the virus to the host cell. Gp160 is the precursor protein that is cleaved into gp120 and gp41 during viral maturation. CXCR4 is a cellular co-receptor used by some strains of HIV to enter host cells but is not directly involved in the fusion process.