Nokea
Which cell type is a sentinel in the tissues and part of the innate immune system?
- A. T lymphocytes
- B. Dendritic cells
- C. B lymphocytes
- D. Plasma cells
Correct Answer: B
Rationale: The correct answer is B: Dendritic cells. Dendritic cells are sentinel cells in tissues that detect pathogens and activate the immune response. They are crucial in initiating adaptive immune responses by presenting antigens to T cells. T lymphocytes (A) are involved in adaptive immunity, not innate immunity. B lymphocytes (C) mature into plasma cells (D) which produce antibodies, but they are not sentinel cells in tissues like dendritic cells.
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A patient who has received a kidney transplant has been admitted to the medical unit with acute rejection and is receiving IV cyclosporine (Sandimmune) and methylprednisolone (Solu-Medrol). Which staff member is best to assign to care for this patient?
- A. An RN who floated to the medical unit from the coronary care unit for the day.
- B. An RN with 3 years of experience in the operating room who is orienting to the medical unit.
- C. An RN who has worked on the medical unit for 5 years and is working a double shift today.
- D. A new graduate RN who needs experience with IV medication administration.
Correct Answer: C
Rationale: An experienced RN who is familiar with the medical unit and its protocols is the best choice for caring for a patient with acute rejection. This patient requires close monitoring and skilled care which an experienced RN can provide. The other options involve RNs who may not be as familiar with the unit or are less experienced.
Which isotype plays a major role in opsonization of antigens?
- A. IgM
- B. IgG
- C. IgA
- D. IgD
Correct Answer: B
Rationale: The correct answer is B: IgG. IgG plays a major role in opsonization by binding to antigens and marking them for phagocytosis. IgM is the first antibody produced in response to an infection but is not as effective in opsonization. IgA primarily protects mucosal surfaces. IgD is involved in the activation of B cells, not opsonization. In summary, IgG is the correct choice due to its specific role in opsonization compared to the other isotypes.
A co-receptor on target cells for HIV is
- A. gp120
- B. CR4
- C. CR5
- D. CXCR4
Correct Answer: D
Rationale: The correct answer is D: CXCR4. CXCR4 is a chemokine receptor that serves as a co-receptor for HIV entry into target cells. Step 1: HIV binds to CD4 receptor on the target cell. Step 2: The viral envelope protein gp120 then interacts with either CXCR4 or CCR5 co-receptor to facilitate viral entry. Step 3: In the case of CXCR4-tropic HIV strains, CXCR4 is the co-receptor used for entry into the target cell. Therefore, choice D is correct. Choices A (gp120) and C (CR5) are incorrect as they are not co-receptors, while choice B (CR4) is not a known co-receptor for HIV entry.
What antibody mediates Type I hypersensitivity?
- A. IgA
- B. IgE
- C. IgG
- D. IgM
Correct Answer: B
Rationale: The correct answer is B: IgE. In Type I hypersensitivity reactions, IgE antibodies are involved. Firstly, upon initial exposure to an allergen, B cells produce IgE antibodies specific to that allergen. IgE antibodies then bind to mast cells and basophils. Upon subsequent exposure to the same allergen, it cross-links the IgE antibodies on mast cells and basophils, leading to degranulation and release of inflammatory mediators like histamine. This results in the symptoms of Type I hypersensitivity reactions.
Choice A (IgA) is incorrect because IgA is mainly involved in mucosal immunity. Choice C (IgG) is incorrect because while IgG can be involved in Type II and Type III hypersensitivity reactions, it is not the primary antibody in Type I hypersensitivity. Choice D (IgM) is incorrect because IgM is typically involved in the primary immune response, not in Type I hypersensitivity reactions.
Which antibody isotype is most abundant in circulation?
- A. IgA
- B. IgG
- C. IgE
- D. IgM
Correct Answer: B
Rationale: The correct answer is B: IgG. IgG is the most abundant antibody isotype in circulation, constituting about 75% of total antibodies. This is because IgG is produced during secondary immune responses and has a longer half-life compared to other isotypes, allowing it to accumulate in circulation. IgA is mainly found in mucosal surfaces, IgE is associated with allergic reactions, and IgM is the first antibody produced in a primary immune response. Therefore, IgG is the most abundant in circulation due to its longevity and role in secondary immune responses.