Nokea
The Fc regions of antibodies play a role in which of the following antibody effector functions:
- A. Degranulation of mast cells
- B. Antibody-dependent cell-mediated cytotoxicity (ADCC)
- C. Complement activation
- D. All of the above
Correct Answer: D
Rationale: The Fc regions of antibodies interact with various immune cells and molecules to mediate effector functions.
- A: Degranulation of mast cells: Fc receptors on mast cells bind to antibody Fc regions, triggering degranulation.
- B: ADCC: Fc regions bind to Fc receptors on immune cells, facilitating target cell killing.
- C: Complement activation: Antibody binding to antigens can activate the complement system via the Fc region.
Therefore, the correct answer is D because the Fc regions of antibodies are involved in all mentioned effector functions.
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What triggers the activation of lymphocytes in adaptive immunity?
- A. Phagocytosis
- B. Recognition of their specific antigen
- C. Cytokine release by macrophages
- D. Opsonization of pathogens
Correct Answer: B
Rationale: The correct answer is B because lymphocytes are activated in adaptive immunity by recognizing their specific antigen. This recognition is crucial for initiating an immune response tailored to combat a specific pathogen. Phagocytosis (A) is the process of engulfing and destroying pathogens, but it does not directly activate lymphocytes. Cytokine release by macrophages (C) can help in activating other immune cells, but lymphocytes specifically require antigen recognition for activation. Opsonization of pathogens (D) enhances phagocytosis but is not the direct trigger for lymphocyte activation.
Which antibody isotype is involved in allergic reactions?
- A. IgG
- B. IgM
- C. IgA
- D. IgE
Correct Answer: D
Rationale: The correct answer is D: IgE. IgE is the antibody isotype involved in allergic reactions. It binds to allergens and triggers the release of histamine and other chemicals, leading to allergic symptoms. IgG (choice A) is involved in long-term immunity, IgM (choice B) is the first antibody produced in response to an infection, and IgA (choice C) is mainly found in mucosal areas and helps prevent pathogens from entering the body. IgE is specifically associated with allergic responses due to its role in triggering the release of inflammatory mediators in response to allergens.
Which scientist proposed the concept of clonal selection?
- A. Paul Ehrlich
- B. Macfarlane Burnet
- C. Louis Pasteur
- D. Elie Metchnikoff
Correct Answer: B
Rationale: The correct answer is B: Macfarlane Burnet. Burnet proposed the concept of clonal selection in the 1950s to explain how the immune system recognizes and responds to specific antigens. He suggested that lymphocytes with receptors specific to antigens undergo clonal expansion upon encountering the antigen. This hypothesis laid the groundwork for our understanding of adaptive immunity.
A: Paul Ehrlich developed the side-chain theory of antibody formation, not clonal selection.
C: Louis Pasteur is known for his work in microbiology and vaccination, not clonal selection.
D: Elie Metchnikoff is credited with discovering phagocytosis, not clonal selection.
A protein-protein interaction domain present both in TLR-4 and MyD88 is:
- A. CARD
- B. TIR
- C. Leucine rich repeat (LRR)
- D. Immunoglobulin-like domain
Correct Answer: B
Rationale: The correct answer is B: TIR. This is because both TLR-4 and MyD88 contain a Toll/interleukin-1 receptor (TIR) domain, which mediates protein-protein interactions in the Toll-like receptor signaling pathway. The other options, such as A (CARD), C (LRR), and D (Immunoglobulin-like domain), are not present in both TLR-4 and MyD88 and do not play a significant role in their interaction in the signaling pathway. This makes B the most appropriate choice as it accurately identifies the common protein-protein interaction domain between TLR-4 and MyD88.
A nurse has educated a client on an epinephrine autoinjector. What statement by the client indicates additional instruction is needed?
- A. I don't need to go to the hospital after using it.
- B. I must carry two autoinjectors with me at all times.
- C. I will write the expiration date on my calendar.
- D. This can be injected right through my clothes.
Correct Answer: A
Rationale: The correct answer is A. If the client states they don't need to go to the hospital after using the epinephrine autoinjector, additional instruction is needed. The rationale is that after using an epinephrine autoinjector, it is crucial to seek medical attention immediately due to the potential for severe allergic reactions. Choice B is incorrect because carrying two autoinjectors is recommended in case the first dose is not effective. Choice C is incorrect as it demonstrates good practice in tracking the expiration date. Choice D is incorrect as it is acceptable to inject through clothes in an emergency situation.