Which of the following best describes the role of the complement system in the inflammatory response?

• A. Enhances the inflammatory response by promoting chemotaxis and increasing vascular permeability.
• B. Directly neutralizes pathogens without influencing inflammation.
• C. Has no effect on the inflammatory response.
• D. Suppresses the inflammatory response by inhibiting cytokine production.

Answer: (A)

Verified step by step guidance

1. Understand the complement system as a part of the innate immune system that helps clear pathogens and damaged cells.
2. Recall that the complement system can be activated through different pathways (classical, lectin, and alternative) leading to a cascade of protein activations.
3. Recognize that one of the key roles of the complement system is to enhance inflammation by producing small peptides (like C3a and C5a) that act as chemotactic factors, attracting immune cells to the site of infection.
4. Note that these complement fragments also increase vascular permeability, allowing immune cells and proteins to move more easily from the bloodstream into the tissues where they are needed.
5. Conclude that the complement system does not suppress inflammation or directly neutralize pathogens without influencing inflammation; rather, it promotes and amplifies the inflammatory response.