Dendritic cells migrating from tissues enter the lymph nodes through

Correct Answer: C

Rationale: The correct answer is C: Afferent lymphatics. Dendritic cells migrate from tissues to lymph nodes through afferent lymphatics, which are small vessels that carry lymph into the lymph nodes. Once inside the lymph nodes, dendritic cells interact with T cells to initiate immune responses. The thoracic duct (A) drains lymph from the entire body into the bloodstream, not directly into lymph nodes. High endothelial venules (HEV) (B) are specialized blood vessels in lymph nodes where lymphocytes enter from the bloodstream, not dendritic cells. Efferent lymphatics (D) carry lymph out of the lymph nodes, not into them.

Correct Answer: E

Rationale: Rationale for Correct Answer (E): E: Surgery is the correct answer. Surgery is not typically used as a primary therapy for autoimmune diseases. Autoimmune diseases are usually treated with medications such as immuno-suppressive drugs (A), anti-inflammatory drugs (B), and targeted therapies like anti-TNF (C) and anti-CD20 (D) to manage symptoms and control the immune response. Surgery is only considered in specific cases when other treatments have failed or for complications related to the autoimmune disease. Therefore, surgery is not a standard therapy for autoimmune diseases. Summary of Incorrect Choices: A: Immuno-suppressive drugs like cortisone are commonly used in autoimmune disease treatment. B: Aspirin is an anti-inflammatory drug that can help manage symptoms in some autoimmune diseases. C: Anti-TNF therapy targets specific molecules involved in the immune response in autoimmune diseases. D: Anti-CD20 therapy targets B cells to modulate the immune response in autoimmune diseases.

Correct Answer: E

Rationale: I'm sorry, but the correct answer is not provided in the choices given. Acquired passive immunity refers to the transfer of antibodies from one individual to another. Breast milk, placental transfer, short-term protection, and disease prevention are all characteristics of acquired passive immunity. Therefore, the correct answer is not presented in the options provided.

Correct Answer: D

Rationale: The correct answer is D because all the choices contribute to the vascular instability observed in severe sepsis. A: Systemic release of cytokines like TNF-α and IL-1β leads to vasodilation and increased capillary permeability. B: Complement activation causes inflammation and vasodilation. C: Release of high levels of lipid mediators like prostaglandins and leukotrienes further exacerbates vasodilation and vascular permeability. Therefore, all these mechanisms combined lead to the vascular instability seen in severe sepsis.

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.