Nokea
What is the primary function of lymph nodes?
- A. Producing red blood cells
- B. Filtering lymph and facilitating immune responses
- C. Synthesizing antibodies
- D. Generating cytokines
Correct Answer: B
Rationale: The primary function of lymph nodes is to filter lymph and facilitate immune responses. Lymph nodes contain immune cells that help recognize and fight off infections. They filter lymph by trapping and removing pathogens and foreign particles. This process helps in activating the immune response to protect the body. Choices A, C, and D are incorrect because lymph nodes do not produce red blood cells, synthesize antibodies, or generate cytokines. These functions are carried out by other organs and cells in the body.
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What is the primary function of anaphylotoxins (e.g., C3a, C4a, C5a) in the immune system?
- A. Suppressing inflammation
- B. Facilitating antigen presentation
- C. Inducing inflammation and recruiting immune cells
- D. Neutralizing pathogens
Correct Answer: C
Rationale: The correct answer is C: Inducing inflammation and recruiting immune cells. Anaphylotoxins, such as C3a, C4a, and C5a, are small molecules that are released during complement activation. They play a crucial role in enhancing inflammation by attracting immune cells to the site of infection or injury.
1. Anaphylotoxins induce inflammation by stimulating the release of histamine and other inflammatory mediators.
2. They promote vasodilation and increase vascular permeability, allowing immune cells to easily reach the affected area.
3. Anaphylotoxins also act as chemoattractants, recruiting neutrophils, macrophages, and other immune cells to the site of inflammation to help fight against pathogens.
4. These molecules do not suppress inflammation (choice A), facilitate antigen presentation (choice B), or neutralize pathogens (choice D). Their primary function is to amplify the immune response by inducing inflammation and recruiting immune cells to combat infections
A monoclonal antibody called '3F8' was developed to treat neuroblastoma and was subsequently improved by:
- A. Making it more specific for neuroblastoma antigens
- B. Engineering a form that has human rather than mouse variable region protein sequences
- C. Engineering a form that has human rather than mouse constant region protein sequences
- D. Two of these responses are correct
Correct Answer: D
Rationale: The correct answer is D. By engineering a form of the antibody with human variable region protein sequences (choice B), it reduces the risk of immune response in patients. Similarly, by engineering a form with human constant region protein sequences (choice C), it further reduces immunogenicity. Therefore, both B and C contribute to making the antibody more suitable for human use, enhancing its efficacy and safety in treating neuroblastoma. Choices A and D are incorrect as they do not address the crucial aspect of reducing immunogenicity through humanization of the antibody.
Many immune cells listed below are found in the absence of infection in the lamina propria of the gut with the exception of:
- A. Neutrophils
- B. Macrophages
- C. Plasma cells
- D. T cells
Correct Answer: A
Rationale: Neutrophils are typically not found in the lamina propria of the gut in the absence of infection because they are primarily involved in the acute inflammatory response to infections. Macrophages, plasma cells, and T cells are commonly present in the gut lamina propria to maintain immune homeostasis and respond to antigens. Neutrophils are more abundant in tissues during active infection due to their role in phagocytosis and inflammation. Therefore, the correct answer is A: Neutrophils.
Which of the following processes does not require the involvement of an antigen-specific T helper cell?
- A. Somatic hypermutation
- B. VDJ gene rearrangement
- C. Immunoglobulin class switching
- D. Memory cell differentiation
Correct Answer: B
Rationale: Correct Answer: B (VDJ gene rearrangement)
Rationale:
1. VDJ gene rearrangement occurs during B cell development in the bone marrow, independent of T helper cells.
2. Somatic hypermutation and immunoglobulin class switching require T helper cell interactions.
3. Memory cell differentiation also involves T helper cells for activation and differentiation.
4. Therefore, VDJ gene rearrangement is the only process not directly dependent on antigen-specific T helper cells.
Which patient is at risk for hypernatremia?
- A. Has a deficiency of aldosterone
- B. Has prolonged vomiting and diarrhea
- C. Receives excessive IV 5% dextrose solution
- D. Has impaired consciousness and decreased thirst sensitivity
Correct Answer: D
Rationale: Impaired consciousness leads to decreased thirst sensitivity, preventing adequate water intake and increasing sodium concentration in the blood.