Nokea
Which cells play a central role in Type I hypersensitivity reactions?
- A. Neutrophils
- B. Mast cells
- C. Macrophages
- D. Dendritic cells
Correct Answer: B
Rationale: The correct answer is B: Mast cells. Mast cells play a central role in Type I hypersensitivity reactions by releasing histamine, cytokines, and other inflammatory mediators in response to allergens. This triggers the allergic response. Neutrophils (A), Macrophages (C), and Dendritic cells (D) are not central to Type I hypersensitivity reactions. Neutrophils are involved in acute inflammation, macrophages play a role in phagocytosis and antigen presentation, and dendritic cells are important in initiating adaptive immune responses.
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A client with AIDS is experiencing bouts of diarrhea,anorexia,nausea and vomiting. Cryptosporidiosis is diagnosed and the nurse goes to hang the first antibiotic. Which type of macrolide antibiotic is the nurse going to hang?
- A. Humatin
- B. Azithromycin
- C. Penicillin
- D. Ancef
Correct Answer: B
Rationale: Azithromycin is a macrolide antibiotic commonly used to treat cryptosporidiosis in AIDS patients.
Macrophages differentiate
- A. From blood neutrophils
- B. In tissues
- C. From the common lymphoid progenitor
- D. In the bone marrow
Correct Answer: B
Rationale: Macrophages differentiate in tissues because they originate from monocytes which leave the bloodstream and mature into macrophages in various tissues. This process is essential for their diverse functions in immune response and tissue maintenance. Choices A, C, and D are incorrect because macrophages do not differentiate from blood neutrophils, the common lymphoid progenitor, or in the bone marrow.
Which of the following best illustrates selective genetic pressure in immune adaptation?
- A. Rroma populations and their genetic response to Yersinia pestis
- B. Mutation rates in viruses like the flu
- C. Increased pathogen diversity in unvaccinated populations
- D. Non-specific activation of innate immunity
Correct Answer: A
Rationale: Step 1: Selective genetic pressure refers to the process where specific genetic traits are favored due to environmental factors.
Step 2: Rroma populations and their genetic response to Yersinia pestis demonstrate selective genetic pressure as they have developed genetic adaptations to resist the plague bacterium.
Step 3: This adaptation is a result of prolonged exposure to the pathogen, leading to the survival and reproduction of individuals with genetic variations that confer resistance.
Step 4: Other choices are incorrect because mutation rates in viruses like the flu (B) do not necessarily involve genetic pressure, increased pathogen diversity in unvaccinated populations (C) is a consequence of lack of immunity, and non-specific activation of innate immunity (D) is not a selective process based on genetic traits.
What are the most common immunosuppressive agents used to prevent rejection of transplanted organs?
- A. Cyclosporine, sirolimus, and muromonab-CD3
- B. Prednisone, polyclonal antibodies, and cyclosporine
- C. Azathioprine, mycophenolate mofetil, and sirolimus
- D. Tacrolimus, prednisone, and mycophenolate mofetil
Correct Answer: D
Rationale: Tacrolimus, prednisone, and mycophenolate mofetil are commonly used to prevent organ rejection.
During the course of an immune response to a given antigen, affinity maturation results in survival of:
- A. B cells whose secretion of antibody occurs at a higher rate
- B. B cells whose antibodies bind the antigen more strongly
- C. T cells whose TCRs bind the antigen more strongly
- D. Both B and C are correct
Correct Answer: B
Rationale: Rationale:
1. Affinity maturation is the process where B cells produce antibodies with increased affinity for the antigen over time.
2. B cells whose antibodies bind the antigen more strongly have higher affinity.
3. Survival of B cells with higher affinity antibodies is crucial for effective immune response.
4. A is incorrect as rate of antibody secretion doesn't necessarily correlate with affinity.
5. C is incorrect as T cells are not directly involved in affinity maturation of antibodies.
6. D is incorrect since T cells are not affected by affinity maturation in the context of this question.