Nokea
Class switching of immunoglobulins occurs
- A. Usually with booster immunizations, going from IgM to IgG
- B. binds complement
- C. causes the histamine release
- D. mediates immunoglobulin class switching
Correct Answer: A
Rationale: The correct answer is A because class switching of immunoglobulins typically occurs during an immune response, leading to the production of antibodies of different classes like IgM to IgG. This process helps enhance the immune response and memory. Choice B, binding complement, refers to the function of antibodies in the classical pathway of the complement system, not class switching. Choice C, causing histamine release, is typically associated with IgE antibodies in allergic reactions, not class switching. Choice D, mediating immunoglobulin class switching, is too vague and does not provide a clear explanation compared to choice A.
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You are working in an AIDS hospice facility that is also staffed with LPNs and nursing assistants. Which of these nursing actions is best to delegate to an LPN you are supervising?
- A. Assess patients’ nutritional needs and individualize diet plans to improve nutrition.
- B. Collect data about the patients’ response to medications used for pain and anorexia.
- C. Teach the nursing assistants about how to lower the risk for spreading infections.
- D. Assist patients with personal hygiene and other activities of daily living as needed.
Correct Answer: B
Rationale: LPNs are trained to collect data and monitor patients’ responses to medications which is within their scope of practice. Assessing nutritional needs and teaching about infection control are more complex tasks that typically require the expertise of an RN. Assisting with personal hygiene is usually delegated to nursing assistants.
Virulence factors can be transferred from pathogenic to non-pathogenic bacterial strains that are part of the normal flora. An example of a commensal bacterial species that has turned into a pathogenic strain is:
- A. E. coli 0157:H7
- B. M. tuberculosis
- C. Group A S. pyogenes
- D. All opportunistic bacterial species
Correct Answer: A
Rationale: The correct answer is A: E. coli 0157:H7. This strain of E. coli has acquired virulence factors that allow it to cause severe illness in humans, such as bloody diarrhea and kidney failure. The transformation of E. coli from a commensal to a pathogenic strain is well-documented. In contrast, choices B and C involve species that are inherently pathogenic and not commensal. Choice D is too broad and includes a wide range of bacterial species that do not necessarily originate from the normal flora. Therefore, E. coli 0157:H7 is the best example of a commensal bacterium that has turned pathogenic due to the acquisition of virulence factors.
The epitopes recognized by T cells are always:
- A. Conformational
- B. Linear
- C. On the antigen surface
- D. Buried inside the antigen
Correct Answer: B
Rationale: The correct answer is B: Linear. T cells recognize linear epitopes, which are sequences of amino acids displayed in a linear fashion on the antigen's surface. This recognition occurs through the T cell receptor binding to the linear epitope. Conformational epitopes (A) involve multiple amino acid residues brought together in a specific three-dimensional structure. Epitopes on the antigen surface (C) are correct, but not all T cell epitopes are necessarily on the surface. Epitopes buried inside the antigen (D) are not accessible to T cell receptors for recognition. Thus, the correct choice is B due to the linear presentation of epitopes for T cell recognition.
Compared to antibodies produced in a primary response to a given antigen, the antibodies produced in a memory response are typically:
- A. More likely to be IgM
- B. More likely to be IgG, IgA and/or IgE
- C. Of lower affinity
- D. Two of these responses are correct
Correct Answer: B
Rationale: Step 1: Memory response produces antibodies of higher affinity due to affinity maturation.
Step 2: Memory response involves class switching, leading to production of IgG, IgA, and IgE.
Step 3: IgM is predominant in primary response, but memory response shifts towards other classes.
Summary: Choice B is correct as memory response produces antibodies of higher affinity and different classes. Choices A and C are incorrect as memory response does not typically result in more IgM or lower affinity antibodies. Choice D is incorrect as only choice B is accurate.
Which historical event provides evidence for immune adaptation?
- A. Spanish flu pandemic
- B. The Black Death caused by Yersinia pestis
- C. HIV/AIDS epidemic
- D. The eradication of smallpox
Correct Answer: B
Rationale: The Black Death caused by Yersinia pestis is the correct answer because it led to immune adaptation in survivors. Yersinia pestis triggered the body to develop immunity. The Spanish flu pandemic, HIV/AIDS epidemic, and eradication of smallpox did not directly result in immune adaptation like the Black Death. The Spanish flu and HIV/AIDS were caused by viruses that did not lead to long-term immunity, and smallpox eradication was achieved through vaccinations, not natural immune adaptation.