Nokea
Attenuated vaccines can be obtained by
- A. Passage through cultured cells
- B. Formaldehyde treatment
- C. The use of viral vectors carrying pathogen subunits
- D. All of the above treatments would lead to attenuated vaccines
Correct Answer: A
Rationale: The correct answer is A: Passage through cultured cells. Attenuated vaccines are produced by weakening the pathogen through serial passages in cultured cells, reducing virulence while maintaining immunogenicity. Formaldehyde treatment (B) disrupts the pathogen's structure and is used for inactivated vaccines. The use of viral vectors carrying pathogen subunits (C) is a method for creating subunit vaccines, not attenuated vaccines. Therefore, D is incorrect as not all treatments lead to attenuated vaccines.
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A patient’s documentation indicates he has a stage III pressure ulcer on his right hip. What should the nurse expect to find on assessment of the patient’s right hip?
- A. Exposed bone, tendon, or muscle
- B. An abrasion, blister, or shallow crater
- C. Deep crater through subcutaneous tissue to fascia
- D. Persistent redness (or bluish color in darker skin tones)
Correct Answer: C
Rationale: Stage III pressure ulcers penetrate through all layers of the skin but do not expose underlying structures such as bone or muscle.
Which of the following statements is NOT true
- A. During T cell development the decision to become a CD4 or a CD8 positive cell is a random event
- B. During T cell differentiation the decision to become a TH1 or a TH2 cell CD4+ is a random event
- C. TH2 CD4+ cells secrete IL-4
- D. IL-10 is TH2 polarizing cytokine
Correct Answer: B
Rationale: The correct answer is B: During T cell differentiation, the decision to become a TH1 or a TH2 cell CD4+ is not a random event. This is because T cell differentiation into TH1 or TH2 cells is guided by specific signals from the environment, such as cytokines present during activation. TH1 cells are induced by IL-12 and IFN-gamma, while TH2 cells are induced by IL-4. This process is not random but rather a result of specific signaling cues.
A: During T cell development, the decision to become a CD4 or a CD8 positive cell is not a random event. It is determined by interactions with thymic stromal cells and the T cell receptor.
C: TH2 CD4+ cells do secrete IL-4, so this statement is true.
D: IL-10 is not a TH2 polarizing cytokine; rather, it is known to have regulatory functions in immune responses.
Mature naïve T cells that leave the thymus
- A. Are all tolerant to self-antigens because all self-reactive developing T cells have been killed in the thymus
- B. Might include some self-reactive T cells that have not been tolerized against a specific Ag
- C. Go first to LN where they acquire the ability to recognize antigen presented by MHC
- D. Go first to LN to be tested for self-reactivity
Correct Answer: B
Rationale: The correct answer is B because mature naïve T cells that leave the thymus can include self-reactive T cells that have not been tolerized against a specific antigen. This is because the process of negative selection in the thymus eliminates most self-reactive T cells but does not catch all of them. Some self-reactive T cells may escape negative selection and circulate as mature naïve T cells. Therefore, it is possible for mature naïve T cells leaving the thymus to include self-reactive T cells that have not been tolerized against a specific antigen.
Choices:
A: This is incorrect because although negative selection in the thymus eliminates most self-reactive T cells, it does not catch all of them, so some self-reactive T cells may still be present in the mature naïve T cell population.
C: This is incorrect because mature naïve T cells already have the ability to recognize antigens presented by MHC, which is developed in the th
What is the primary role of phagocytosis in innate immunity?
- A. Killing cancer cells
- B. Engulfing and digesting pathogens
- C. Producing antibodies
- D. Activating complement proteins
Correct Answer: B
Rationale: The primary role of phagocytosis in innate immunity is to engulf and digest pathogens. Phagocytes such as macrophages and neutrophils recognize and engulf bacteria, viruses, and other harmful substances to prevent infections. They digest these pathogens using enzymes and destroy them. This process is crucial in the initial defense against infections. Option A is incorrect because phagocytosis primarily targets pathogens, not cancer cells. Option C is incorrect because producing antibodies is a function of adaptive immunity, not innate immunity. Option D is incorrect because activating complement proteins is a separate mechanism in the immune response.
What outcome would you least expect if the amount of template in a PCR fell significantly below the optimal amount?
- A. non-specific amplification
- B. increased yield
- C. Allelic drop-out (some alleles fail to amplify)
- D. Longer targets amplify poorly or fail
Correct Answer: B
Rationale: The correct answer is B: increased yield. If the amount of template in a PCR falls significantly below the optimal amount, it would be expected to result in a decreased yield rather than an increased yield. The template is essential for DNA amplification in PCR, and a lower amount would lead to fewer copies being produced. Non-specific amplification (choice A) can occur if there is too much template or incorrect primer annealing. Allelic drop-out (choice C) is likely to happen if there is insufficient template present to amplify all alleles. Longer targets amplifying poorly or failing (choice D) is also a common outcome when template concentration is low. Therefore, the least expected outcome would be an increased yield as that goes against the principle of PCR amplification.