Nokea
Which of the following is not usually observed in severe Covid-19 cases?
- A. Prompt and sustained production of type I Interferon
- B. Autoantibodies
- C. A delayed CD4 T cell response
- D. Elevated levels of inflammatory cytokines
Correct Answer: A
Rationale: Step-by-step rationale:
1. In severe Covid-19 cases, there is usually a dysregulated immune response.
2. Type I Interferon plays a crucial role in early antiviral defense.
3. However, in severe cases, there is often a blunted or delayed response of type I Interferon.
4. This delayed response contributes to viral persistence and hyperinflammation.
5. Therefore, the prompt and sustained production of type I Interferon is not usually observed in severe Covid-19 cases.
Summary:
- Choice A is correct as the prompt and sustained production of type I Interferon is not typically observed in severe Covid-19 cases.
- Choices B, C, and D are incorrect as autoantibodies, a delayed CD4 T cell response, and elevated levels of inflammatory cytokines are commonly observed in severe Covid-19 cases.
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What is the immunologic term to indicate the process that eliminates developing T cells whose T-cell receptors bind too strongly to self-peptide/MHC complexes?
- A. Negative selection
- B. Positive selection
- C. Peripheral tolerance
- D. Lineage commitment
Correct Answer: A
Rationale: Negative selection is the correct answer because it refers to the process that eliminates developing T cells with high affinity for self-peptide/MHC complexes to prevent autoimmune reactions. During negative selection, T cells that bind too strongly to self-antigens are deleted or rendered functionally inactive. This ensures that only T cells with moderate affinity for self-antigens are allowed to mature and participate in immune responses.
Summary of other choices:
B: Positive selection involves the selection of T cells that can recognize self-peptide/MHC complexes, promoting their maturation and survival.
C: Peripheral tolerance refers to mechanisms that maintain self-tolerance in the mature immune system, not specifically related to eliminating self-reactive T cells during development.
D: Lineage commitment is the process by which precursor cells differentiate into specific immune cell types and is not directly related to eliminating self-reactive T cells.
A patient with acquired immunodeficiency syndrome (AIDS) has a negative tuberculosis (TB) skin test. Which nursing action is indicated next?
- A. Obtain a chest x-ray and sputum smear.
- B. No further action is needed after the negative skin test.
- C. Teach about the anti-tuberculosis drug isoniazid (INH).
- D. Schedule TB testing again in 6 months.
Correct Answer: A
Rationale: A negative TB skin test in an immunocompromised patient such as one with AIDS does not rule out TB infection. Further diagnostic testing such as a chest x-ray and sputum smear is necessary to confirm the absence of TB. Teaching about INH or scheduling another test is premature without further diagnostic confirmation.
To produce better flu vaccines we want:
- A. To block spreading of the infection by inducing a cytotoxic T cell response that would directly prevent viral entry into uninfected cells
- B. To induce the formation of highly strain-specific neutralizing antibodies that would prevent viral entry into uninfected cells
- C. To induce antibodies able to recognize HA across different strains by targeting less variable regions of HA
- D. All of the above is reasonably expected to improve the success of flu vaccines
Correct Answer: C
Rationale: The correct answer is C because inducing antibodies that can recognize the less variable regions of the Hemagglutinin (HA) protein across different strains allows for cross-protection against various flu strains. This approach is effective as it targets conserved regions of the virus, increasing the likelihood of providing broad immunity. Option A focuses on cytotoxic T cell response, which primarily targets infected cells and may not prevent viral entry into uninfected cells. Option B, on the other hand, is limited to highly strain-specific neutralizing antibodies, which may not provide adequate protection against evolving flu strains. Therefore, option C is the most effective in producing better flu vaccines by targeting less variable regions of HA for broader immunity.
Which T lymphocytes are involved in direct attack and destruction of foreign pathogens?
- A. Dendritic cells
- B. Natural killer cells
- C. T helper (CD4) cells
- D. T cytotoxic (CD8) cells
Correct Answer: D
Rationale: T cytotoxic (CD8) cells directly attack and destroy infected or abnormal cells, making them crucial for eliminating pathogens.
What are examples of type I or IgE-mediated hypersensitivity reactions (select all that apply)?
- A. Asthma
- B. Urticaria
- C. Angioedema
- D. Allergic rhinitis
Correct Answer: A
Rationale: Type I hypersensitivity reactions involve IgE-mediated responses, including asthma, urticaria, angioedema, and allergic rhinitis.