Nokea
Which of the following best describes granuloma formation?
- A. IgE-mediated mast cell activation
- B. Persistent recruitment of macrophages around undigested antigens
- C. Deposition of immune complexes in tissues
- D. Complement-mediated cell lysis
Correct Answer: B
Rationale: Granuloma formation is characterized by the persistent recruitment of macrophages around undigested antigens. Initially, macrophages attempt to phagocytose the antigen but fail to digest it completely, leading to the formation of a granuloma. This process is a protective mechanism to isolate the antigen and prevent its spread. IgE-mediated mast cell activation (choice A) is associated with allergic reactions, not granuloma formation. Deposition of immune complexes in tissues (choice C) is linked to immune complex-mediated diseases, not granuloma formation. Complement-mediated cell lysis (choice D) involves the destruction of target cells by the complement system, which is not directly related to granuloma formation.
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Developing T cells in the thymus can express
- A. Both CD4 and CD8
- B. Only CD4
- C. Only CD8
- D. Neither CD4 or CD8
Correct Answer: A
Rationale: The correct answer is A because developing T cells initially express both CD4 and CD8 co-receptors in the thymus. This stage is crucial for T cell maturation and selection. Eventually, T cells undergo positive and negative selection processes to become either CD4+ helper T cells or CD8+ cytotoxic T cells based on their specificity and function. Choices B and C are incorrect because T cells initially express both CD4 and CD8. Choice D is also incorrect as T cells do express either CD4 or CD8 during their development in the thymus.
After teaching a patient with HIV infection about using antiretroviral drugs, the nurse recognizes that further teaching is needed when the patient says
- A. I should never skip doses of my medication, even if I develop side effects.
- B. If my viral load becomes undetectable, I will no longer be able to transmit HIV to others.
- C. I should not use any over-the-counter drugs without checking with my health care provider.
- D. If I develop a constant headache that is not relieved with aspirin or acetaminophen, I should report it within 24 hours.
Correct Answer: B
Rationale: Even with an undetectable viral load, HIV can still potentially be transmitted, especially during certain activities like unprotected sex.
The nurse is reviewing the immune system with a patient newly diagnosed with an autoimmune disorder. What should the nurse explain as the purpose of antibodies?
- A. They destroy foreign antigens.
- B. Work on many different antigens
- C. Are specific according to blood type
- D. Attach to antigens to label them for destruction
Correct Answer: D
Rationale: The correct answer is D. Antibodies attach to antigens to label them for destruction. This is crucial in the immune response to identify and mark harmful substances for elimination. Choice A is incorrect because antibodies do not destroy antigens directly. Choice B is incorrect as antibodies are specific to particular antigens. Choice C is incorrect as blood type specificity is determined by different antigens, not antibodies.
Select the correct number of statements that are true.
- A. Only 1 and 3 are correct.
- B. Only 2 and 4 are correct.
- C. Only 3 and 4 are correct.
- D. All of the above are correct.
Correct Answer: A
Rationale: The correct answer is A. Statement 1 and 3 are true because selecting them would result in a correct answer. Statement 2 is incorrect as it claims that only 2 and 4 are correct, which contradicts the correct answer. Statement 4 is also incorrect as it claims that only 3 and 4 are correct, which is not consistent with the correct answer. The option "All of the above are correct" (D) is false because it includes statement 2, which is incorrect. Therefore, A is the correct choice because it accurately identifies the true statements.
Which of the following is a molecule that inhibits T cell activation, is highly expressed in Tregs and is used in a recombinant (synthetic) form to treat some autoimmune diseases?
- A. CD86
- B. CTLA-4
- C. MHC class II
- D. CD4
Correct Answer: B
Rationale: The correct answer is B: CTLA-4. CTLA-4 inhibits T cell activation by binding to CD80/CD86 on antigen-presenting cells, preventing the co-stimulatory signal required for T cell activation. It is highly expressed in Tregs, which suppress immune responses. Recombinant CTLA-4 (e.g., abatacept) is used to treat autoimmune diseases by blocking T cell activation.
Explanation for other choices:
A: CD86 is a co-stimulatory molecule that activates T cells, not inhibits them.
C: MHC class II molecules present antigens to T cells, they do not inhibit T cell activation.
D: CD4 is a co-receptor that helps T cells recognize antigens presented by MHC class II molecules, it does not inhibit T cell activation.