Which would result from a lack of TNF?

Which would result from a lack of TNF?

• A. Decreased ability to fight gram-negative bacterial infections
• B. Increased expression of class II MHC molecules
• C. Decreased survival of cancer cells
• D. Increased risk of septic shock

Answer: (A)

TNF is a key proinflammatory cytokine produced by macrophages in response to bacterial components like LPS. It helps mount the early innate immune response by activating macrophages and neutrophils, increasing endothelial adhesion molecule expression to recruit immune cells, and driving the overall inflammatory cascade needed to contain infections, especially extracellular Gram-negative bacteria. If TNF is lacking, this inflammatory signaling is blunted, so the body has a harder time recruiting and activating the cells that kill bacteria. That leads to a decreased ability to fight Gram-negative infections. The other options don't fit because TNF influences many aspects of inflammation, but its absence would not specifically cause increased MHC class II expression, and TNF can contribute to tumor cell death—its absence would more likely allow cancer cells to survive better rather than die. Additionally, TNF at high levels is a driver of septic shock, so lacking TNF would not increase, and would more likely decrease, the risk of septic shock.

TNF is a key proinflammatory cytokine produced by macrophages in response to bacterial components like LPS. It helps mount the early innate immune response by activating macrophages and neutrophils, increasing endothelial adhesion molecule expression to recruit immune cells, and driving the overall inflammatory cascade needed to contain infections, especially extracellular Gram-negative bacteria.

If TNF is lacking, this inflammatory signaling is blunted, so the body has a harder time recruiting and activating the cells that kill bacteria. That leads to a decreased ability to fight Gram-negative infections.

The other options don't fit because TNF influences many aspects of inflammation, but its absence would not specifically cause increased MHC class II expression, and TNF can contribute to tumor cell death—its absence would more likely allow cancer cells to survive better rather than die. Additionally, TNF at high levels is a driver of septic shock, so lacking TNF would not increase, and would more likely decrease, the risk of septic shock.