Nokea
Why is smallpox considered a factor that greatly helped European explorers to defeat the Native populations of the Americas (e.g. Mexico)?
- A. When the Europeans arrived there was an ongoing smallpox epidemic in the Americas that weakened the ability of the Natives to fight back
- B. The Native populations used a form of vaccination against smallpox that was often lethal and therefore they lost more lives.
- C. Smallpox was introduced in Mexico by the European explorers therefore the Native population had no immunity to it and the disease spread rapidly
- D. Both A and B are correct
Correct Answer: C
Rationale: The correct answer is C because smallpox was indeed introduced to the Americas by European explorers, leading to devastating effects on the Native populations who had no immunity. This weakened the Natives' ability to fight back against the Europeans. Option A is incorrect as there was no ongoing smallpox epidemic in the Americas before the arrival of the Europeans. Option B is also incorrect as there is no evidence that the Native populations used a lethal form of vaccination against smallpox. Option D is incorrect as only option C accurately explains the impact of smallpox on the Native populations in relation to European conquest.
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If the BCR of a developing cell has no binding affinity for self-antigens in the bone marrow the B cell will be:
- A. Clonally deleted
- B. Anergized
- C. A possible cause of autoimmunity in the periphery
- D. Allowed to mature and enter the periphery
Correct Answer: D
Rationale: The correct answer is D: Allowed to mature and enter the periphery. In this scenario, since the developing B cell has no binding affinity for self-antigens in the bone marrow, it will not undergo clonal deletion or anergy. Therefore, it will be allowed to mature and enter the periphery where it can encounter foreign antigens and participate in the immune response. Choices A and B are incorrect because clonal deletion and anergy are mechanisms used to eliminate or inactivate self-reactive B cells to prevent autoimmunity. Choice C is incorrect because a B cell without self-binding affinity is not a cause of autoimmunity in the periphery.
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.
T cell receptor and B cell receptor genes both undergo:
- A. Somatic hypermutation
- B. Germline gene rearrangement
- C. Isotype switching
- D. Both A and B are correct
Correct Answer: B
Rationale: The correct answer is B, germline gene rearrangement. T cell receptor and B cell receptor genes both undergo germline gene rearrangement during lymphocyte development, where gene segments are rearranged to generate diverse antigen receptor specificities. Somatic hypermutation and isotype switching are processes specific to B cells in the adaptive immune response, not T cells. Therefore, choices A and C are incorrect. Choice D is incorrect as well since somatic hypermutation is not a process involved in T cell receptor gene rearrangement.
Select the wrong statement concerning TLR4
- A. TLR4 is expressed on dendritic cells and macrophages
- B. It represents an example of a phagocytic receptor
- C. It is expressed on the membrane in complex with a protein called MD2
- D. Mice resistant to endotoxic shock harbor a mutation of TLR4
Correct Answer: B
Rationale: The correct answer is B because TLR4 is not a phagocytic receptor, but rather a pattern recognition receptor involved in recognizing pathogen-associated molecular patterns (PAMPs).
A: Correct, TLR4 is expressed on dendritic cells and macrophages.
C: Correct, TLR4 is expressed on the membrane in complex with MD2.
D: Correct, mice resistant to endotoxic shock have a mutation in TLR4, indicating its role in the immune response to endotoxins.
A patient is experiencing an immune response that involves the T lymphocytes. For which types of immunity should the nurse plan care for this patient?
- A. Passive immunity
- B. Humoral immunity
- C. Acquired immunity
- D. Cell-mediated immunity
Correct Answer: D
Rationale: The correct answer is D: Cell-mediated immunity. T lymphocytes are primarily involved in cell-mediated immunity, where they directly attack infected cells or pathogens. This type of immunity is crucial in fighting intracellular pathogens like viruses. Other choices are incorrect because:
A: Passive immunity involves receiving pre-formed antibodies, not T lymphocytes.
B: Humoral immunity involves B cells producing antibodies, not T lymphocytes.
C: Acquired immunity is a general term encompassing both humoral and cell-mediated immunity, but T lymphocytes specifically play a key role in cell-mediated immunity.