Nokea
A main cytokine produced by CD4+ TH1 cells is
- A. IL-4
- B. IL-10
- C. IL-5
- D. IFN-γ
Correct Answer: D
Rationale: The correct answer is D: IFN-γ. CD4+ TH1 cells are known to primarily produce interferon-gamma (IFN-γ). This cytokine plays a crucial role in promoting cell-mediated immunity and enhancing the activity of macrophages. IL-4 (choice A) is produced by CD4+ TH2 cells and promotes humoral immunity. IL-10 (choice B) is an anti-inflammatory cytokine produced by various immune cells. IL-5 (choice C) is predominantly produced by CD4+ TH2 cells and is involved in eosinophil activation. Therefore, the main cytokine produced by CD4+ TH1 cells is IFN-γ, making choice D the correct answer.
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Some top-selling drugs that are currently prescribed to treat certain immune-mediated diseases are actually monoclonal antibodies specific for:
- A. An inflammatory cytokine
- B. An inflammatory cytokine receptor
- C. Lymphocytes of the T cell lineage
- D. Two of these responses are correct
Correct Answer: D
Rationale: The correct answer is D because some top-selling drugs for immune-mediated diseases target either an inflammatory cytokine or its receptor. Monoclonal antibodies specific for an inflammatory cytokine can block its activity, while those targeting the receptor can prevent the cytokine from binding and triggering immune responses. Choices A and B are correct examples of drugs targeting inflammatory pathways. Choice C, targeting T cell lymphocytes, is less common for immune-mediated diseases compared to targeting cytokines or receptors. Therefore, D is the correct answer as it encompasses both common targeting strategies.
What cytokine is produced by Regulatory T cells to suppress immune responses?
- A. IL-2
- B. IL-10
- C. IFN-gamma
- D. TNF-alpha
Correct Answer: B
Rationale: The correct answer is B: IL-10. Regulatory T cells produce IL-10 to suppress immune responses by inhibiting the activation and function of other immune cells. IL-2 (A) is mainly produced by activated T cells to promote proliferation. IFN-gamma (C) is produced by T cells and NK cells to enhance immune response. TNF-alpha (D) is produced by macrophages and T cells to induce inflammation. IL-10 stands out as the suppressor cytokine in this context.
Which defense function is a specialty of both IgG and IgA antibody?
- A. Neonatal immunity
- B. Opsonization
- C. Antibody-mediated degranulation of mast cells
- D. Complement activation
Correct Answer: B
Rationale: The correct answer is B: Opsonization. Both IgG and IgA antibodies can participate in opsonization, which involves tagging pathogens for destruction by phagocytes. IgG and IgA have specific receptors on phagocytes that recognize the tagged pathogens, enhancing their clearance. Neonatal immunity (choice A) is primarily mediated by IgG antibodies transferred from mother to fetus. Antibody-mediated degranulation of mast cells (choice C) is mainly associated with IgE antibodies in allergic reactions. Complement activation (choice D) mainly involves IgM and IgG antibodies, leading to a cascade of reactions for pathogen elimination.
What was atypical about the 2009 H1N1 pandemic?
- A. It emerged entirely as an assortment of human strains, while typical pandemics are caused by newly generated animal strains
- B. It was a newly assorted virus unrelated to the human strains that were circulating worldwide in 2009
- C. It was a variant of 1918 H1N1 that is still circulating in pigs
- D. It did not affect the very young, an age group typically struck by flu viruses
Correct Answer: B
Rationale: The correct answer is B because the 2009 H1N1 pandemic was caused by a newly assorted virus unrelated to existing human strains. This is atypical as typical pandemics are caused by animal strains. Option A is incorrect because the 2009 H1N1 pandemic did not emerge entirely as an assortment of human strains. Option C is incorrect as the 2009 H1N1 virus was not a variant of the 1918 H1N1 strain circulating in pigs. Option D is incorrect because the 2009 H1N1 pandemic did affect individuals across all age groups, including the very young.
A heart attack is
- A. damage to cardiac muscle
- B. Typically from a blocked coronary artery
- C. Death of brain tissue from blocked arteries in the head
- D. A & b
Correct Answer: D
Rationale: The correct answer is D because a heart attack, also known as a myocardial infarction, involves damage to the cardiac muscle due to a blocked coronary artery. Choice A is correct as it directly relates to the definition of a heart attack. Choice B is also correct as a blocked coronary artery is the main cause of decreased blood flow to the heart muscle leading to a heart attack. Choice C is incorrect as it refers to a stroke, which is the death of brain tissue due to blocked arteries in the head, not a heart attack. Therefore, A & B (choices A and B) are the correct options, making D the correct answer.