Nokea
The most abundant class of immunoglobulin in serum is
- A. IgE
- B. IgA
- C. IgD
- D. IgG
Correct Answer: D
Rationale: The correct answer is D: IgG. IgG is the most abundant class of immunoglobulin in serum, constituting about 75% of total immunoglobulins. IgG plays a crucial role in humoral immunity, providing long-term protection against pathogens. IgE (A) is involved in allergic responses, IgA (B) is mainly found in mucosal secretions, and IgD (C) functions as a cell surface receptor on B cells. IgG is the primary immunoglobulin responsible for secondary immune responses and provides the bulk of the adaptive immune response.
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Pattern recognition receptors (PRR) can be found
- A. In soluble form in the blood
- B. In the cytosol of cells
- C. On endosomal membranes
- D. All of the above are correct
Correct Answer: D
Rationale: Pattern recognition receptors (PRRs) are a class of receptors that recognize specific molecular patterns associated with pathogens. They can be found in various locations within the body, including in soluble form in the blood (Choice A), in the cytosol of cells (Choice B), and on endosomal membranes (Choice C). Therefore, the correct answer is D, "All of the above are correct," as PRRs can indeed be located in all of these locations. PRRs play a crucial role in the innate immune response by detecting and responding to pathogens, making their presence in multiple cellular compartments essential for effective immune surveillance and defense.
A 28-year-old male Gulf War veteran tells the nurse he gets a headache, sore throat, shortness of breath, and nausea when his girlfriend wears perfume and when he was painting her apartment. He is afraid he has cancer. What does the nurse suspect may be the patient’s problem?
- A. He has posttraumatic stress disorder.
- B. He has multiple chemical sensitivities.
- C. He needs to wear a mask when he paints.
- D. He is looking for an excuse to break up with his girlfriend.
Correct Answer: B
Rationale: Multiple chemical sensitivities could explain the patient's symptoms triggered by exposure to various chemicals.
What is the role of complement component C3b in immune responses?
- A. Initiates MAC formation
- B. Acts as an opsonin to enhance phagocytosis
- C. Triggers inflammation
- D. Neutralizes cytokines
Correct Answer: B
Rationale: The correct answer is B: C3b acts as an opsonin to enhance phagocytosis. C3b binds to pathogens and enhances their recognition by phagocytic cells, facilitating their engulfment and destruction. This process is crucial for efficient immune responses. A, MAC formation, is initiated by the membrane attack complex, not C3b. C, inflammation, is triggered by various mediators such as histamine and cytokines, not C3b. D, neutralizing cytokines, is not a function of C3b; cytokines are regulatory proteins involved in immune responses.
NOD2
- A. Is a cytosolic receptor for bacteria
- B. Is mutated in 30% of patients with Crohn's disease
- C. Activates NFκB
- D. All of the above is correct
Correct Answer: D
Rationale: Step-by-step rationale:
1. NOD2 is a cytosolic receptor for bacteria, detecting bacterial molecules.
2. Mutations in NOD2 are found in 30% of patients with Crohn's disease.
3. NOD2 activation triggers NFκB signaling pathway.
4. Therefore, all the statements (A, B, C) are correct, making option D the correct answer. Other choices are incorrect as they do not encompass all the correct statements about NOD2.
A major effector function of TH2 cells is:
- A. Protection against intracellular bacteria
- B. Protection against parasitic worms
- C. Regulation of the adaptive immune response through the secretion of anti-inflammatory cytokines
- D. Activation of macrophages
Correct Answer: B
Rationale: The correct answer is B because TH2 cells play a crucial role in protecting against parasitic worms by secreting cytokines that promote eosinophil activation and antibody production. This response helps to expel the parasites from the body.
Incorrect choices:
A: TH1 cells are responsible for protection against intracellular bacteria.
C: TH3 cells, not TH2 cells, are known for secreting anti-inflammatory cytokines.
D: Activation of macrophages is primarily mediated by TH1 cells through IFN-gamma secretion.