Nokea
The gut immune system at homeostasis is 'tolerogenic'. This is achieved by:
- A. The production of anti-inflammatory cytokines such as TGF-beta by resident dendritic cells
- B. Responding to innocuous microbiota antigens with production of antimicrobial peptides that limit microbiota overgrowth
- C. Induction of Tregs
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D. Resident dendritic cells in the gut produce anti-inflammatory cytokines like TGF-beta, promoting tolerance. The production of antimicrobial peptides in response to microbiota antigens helps maintain a balance with the microbiota. Induction of regulatory T cells (Tregs) also plays a crucial role in preventing excessive immune responses. Therefore, all of the choices (A, B, and C) contribute to maintaining gut immune system homeostasis by promoting tolerance and preventing inflammation.
You may also like to solve these questions
CD3 is a complex of proteins involved in
- A. Antigen binding
- B. Signal propagation in T cells
- C. Signal propagation in B cells
- D. T cell homing to lymph nodes
Correct Answer: B
Rationale: The correct answer is B: Signal propagation in T cells. CD3 is a protein complex found on the surface of T cells that is crucial for T cell receptor signaling and activation. It helps propagate signals within T cells, leading to T cell activation and immune responses. Choice A (Antigen binding) is incorrect as CD3 is not directly involved in antigen binding. Choice C (Signal propagation in B cells) is incorrect as CD3 is specific to T cells, not B cells. Choice D (T cell homing to lymph nodes) is incorrect as CD3 is not responsible for the physical migration of T cells to lymph nodes.
The annotation D refers to which DNA component?
- A. Plasmid DNA
- B. Vector DNA
- C. Insert DNA
- D. Recombinant DNA
Correct Answer: D
Rationale: The correct answer is D: Recombinant DNA. Recombinant DNA refers to the DNA molecule formed by combining DNA from different sources. In genetic engineering, this is created by inserting a foreign DNA fragment into a vector DNA, resulting in a new DNA molecule. Plasmid DNA (A) is a small, circular DNA found in bacteria. Vector DNA (B) is a carrier molecule used to transport foreign DNA into a host cell. Insert DNA (C) is the DNA fragment that is inserted into a vector. Therefore, choice D is the correct answer as it specifically refers to the combined DNA molecule formed in genetic engineering.
A critical role of secondary lymphoid tissues is to:
- A. Provide a place for B and T lymphocytes to mature and begin expression of antigen receptors
- B. Allow co-localization of the components required to activate naïve lymphocytes
- C. Minimize contact of naïve lymphocytes with self antigens
- D. All of the above
Correct Answer: B
Rationale: Step 1: Secondary lymphoid tissues bring together antigen-presenting cells and lymphocytes, facilitating the activation of naïve lymphocytes.
Step 2: Co-localization of these components is essential for efficient immune response initiation.
Step 3: Maturation and expression of antigen receptors primarily occur in primary lymphoid tissues, not secondary.
Summary:
A: Incorrect. Maturation of lymphocytes occurs mainly in primary lymphoid tissues.
C: Incorrect. Contact with self-antigens is necessary for self-tolerance and occurs in primary lymphoid tissues.
D: Incorrect. Only choice B accurately describes the critical role of secondary lymphoid tissues.
The 'rapid' HIV antibody testing is performed on a patient at high risk for HIV infection. What should the nurse explain about this test?
- A. The test measures the activity of the HIV and reports viral loads as real numbers.
- B. This test is highly reliable, and in 5 minutes the patient will know if HIV infection is present.
- C. If the results are positive, another blood test and a return appointment for results will be necessary.
- D. This test detects drug-resistant viral mutations that are present in viral genes to evaluate resistance to antiretroviral drugs.
Correct Answer: C
Rationale: While rapid tests provide preliminary results quickly, confirmatory testing is required for accurate diagnosis.
TLRs contain a cytoplasmic TIR domain also found in the receptor of
- A. Type I Interferons
- B. IL-1β
- C. TNF-α
- D. IL-8
Correct Answer: B
Rationale: Step-by-step rationale for Choice B (IL-1β) being correct:
1. The TIR domain is present in Toll-like receptors (TLRs) and IL-1 receptor.
2. TLRs recognize various microbial products, while IL-1 receptor binds IL-1 cytokines.
3. Both TLRs and IL-1 receptor signal through the TIR domain.
4. IL-1β is a cytokine that binds to IL-1 receptor, which contains a TIR domain.
Summary of why the other choices are incorrect:
A: Type I Interferons - Type I interferons signal through JAK-STAT pathway, not TIR domain.
C: TNF-α - TNF receptor family signals through TNF receptor-associated death domain, not TIR domain.
D: IL-8 - IL-8 binds to CXCR1 and CXCR2 receptors, which do not contain a TIR domain.
In summary, Choice B