Which of the following is a major action of chemical mediators in inflammation?

• A. Bring in or attract leukocytes
• B. Inhibit leukocyte function
• C. Increase blood viscosity
• D. Destroy bacteria directly

Answer: (B)

The main idea is that chemical mediators of inflammation primarily act to recruit leukocytes to the site of injury. They create signals—chemokines and other mediators like C5a and leukotriene B4—that guide neutrophils and monocytes from the blood into the inflamed tissue. This chemotactic recruitment, together with upregulation of adhesion molecules on endothelium and increased vascular permeability, orchestrates the rapid arrival and activation of leukocytes to curb the threat.

So bringing in or attracting leukocytes is the key action because the inflammatory response hinges on getting immune cells to where they’re needed. In contrast, inhibiting leukocyte function would dampen the response rather than drive it, increasing viscosity isn’t a primary mediator effect, and directly destroying bacteria isn’t a typical primary action of inflammatory mediators themselves (their job is to coordinate and amplify leukocyte defenses that actually kill microbes).