What is the role of macrophages in granuloma formation?

Correct Answer: B

Rationale: The correct answer is B because macrophages play a crucial role in granuloma formation by engulfing antigens but failing to destroy them, leading to the formation of a cluster of immune cells to contain the persistent antigen. Macrophages present antigens to T cells, triggering an immune response. Other choices are incorrect as macrophages do not neutralize histamine, stimulate IgE production, or produce antibodies against antigens in the context of granuloma formation.

Correct Answer: E

Rationale: In this question, the correct answer is missing. However, based on the context provided, let's analyze the options to provide a detailed educational rationale. The correct answer is likely to be option D) Follicles. Within the lymph node, B cells receive T cell help for antibody production in specialized areas called germinal centers within the follicles. This is where B cells proliferate, differentiate, and undergo class switching to produce high-affinity antibodies. Option A) Paracortex is incorrect because it mainly consists of T cells and is responsible for T cell activation. Option B) Medulla is not the correct answer as it is involved in filtering lymph and contains plasma cells. Option C) Cortex is also not the right choice as it houses dendritic cells that present antigens to T cells but not specifically involved in B cell antibody production. In an educational context, understanding the specific structures and functions within lymph nodes is crucial for comprehending the immune response. Knowing where and how B cells receive T cell help is fundamental in understanding the coordination of immune responses and the production of antibodies to combat pathogens effectively.

Correct Answer: B

Rationale: The correct answer is B: Lupus. Lupus is a systemic autoimmune disease that can affect multiple organs and tissues throughout the body, rather than being specific to a single organ. Multiple sclerosis (A) is a neurological autoimmune disease affecting the central nervous system. Diabetes (C) is an autoimmune disease that affects the pancreas. Hashimoto's thyroiditis (D) is an autoimmune disease targeting the thyroid gland. Lupus does not specifically target a single organ, making it the correct choice.

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: The correct answer to the question linking the cytokine storm associated with SARS and Avian Flu to is option E) Dysregulation of the immune response. This answer is correct because a cytokine storm is an overactive immune response where the body releases excessive levels of pro-inflammatory cytokines, leading to systemic inflammation and tissue damage. In the context of SARS and Avian Flu, this dysregulation can result in a cytokine storm, contributing to the severity of the diseases. Option A) Elevated levels of ROS during these infections in the lung is incorrect because while reactive oxygen species (ROS) can contribute to tissue damage, it is not directly linked to the cytokine storm in these specific infections. Option B) Elevated levels of acute phase proteins is incorrect because acute phase proteins are part of the innate immune response but are not directly responsible for the cytokine storm seen in SARS and Avian Flu. Option C) Formation of the inflammasome through activation of NLRP3 is incorrect because while the inflammasome plays a role in inflammatory responses, it is not the primary mechanism behind the cytokine storm in these infections. Option D) Recognition of oxidized forms of a host lipid called PAPC by TLR4 is incorrect because this mechanism is specific to lipid metabolism and TLR4 signaling, not directly related to the cytokine storm observed in SARS and Avian Flu. In an educational context, understanding the mechanisms underlying cytokine storms is crucial for healthcare professionals to effectively manage and treat severe infections. Recognizing the triggers and pathways involved in excessive immune responses can guide therapeutic interventions to mitigate the detrimental effects of cytokine storms.