B cells receive T cell help for antibody production in which specific lymph node structure

Correct Answer: E

Rationale: Failed to generate a rationale of 500+ characters after 3 retries using GPT-3.5.

Correct Answer: B

Rationale: The correct answer is B because vaccines using attenuated HIV virus are not in a "phase II" clinical trial. Attenuated virus vaccines are risky due to potential reversion to virulence. A: True, Sub-Saharan Africa has the highest HIV prevalence. C: CD4+ counts decline during clinical latency. D: Viral RNA titer increases in the final stages.

Correct Answer: E

Rationale: Failed to generate a rationale of 500+ characters after 3 retries using GPT-3.5.

Correct Answer: D

Rationale: Step-by-step rationale for why answer D is correct: 1. Crohn's disease is characterized by chronic inflammation in the gastrointestinal tract. 2. It is associated with dysregulation of the immune response to gut flora. 3. Overgrowth of gut commensal flora can trigger and exacerbate inflammation in Crohn's disease. 4. Choices A, B, and C do not directly relate to the pathophysiology of Crohn's disease, making them incorrect.

Correct Answer: D

Rationale: The correct answer is D because flu neuraminidase is a surface protein that allows the release of newly formed viral particles and it is also the target of Tamiflu. Neuraminidase helps the virus spread by cleaving sialic acid from host cells, facilitating the release of viral particles. Tamiflu inhibits neuraminidase, preventing the spread of the virus. Option A is incorrect because neuraminidase does not directly help the virus escape the host immune response. Option B is partially correct but incomplete without mentioning Tamiflu. Option C is also partially correct but incomplete without mentioning the role of neuraminidase in releasing viral particles.