Which of the following is a function of acute phase reactants?

• A. Reducing blood vessel permeability
• B. Enhancing opsonization of bacteria
• C. Inhibiting immune response
• D. Increasing the number of leukocytes

Answer: (B)

Acute phase reactants play a vital role in the body's response to inflammation and infection. They are proteins whose concentrations increase or decrease in response to inflammatory cytokines during an acute phase response. One of their primary functions is to enhance opsonization, which is the process whereby pathogens are marked for destruction by immune cells.

When bacteria are opsonized, these acute phase reactants bind to their surfaces. This binding enhances the ability of phagocytic cells, such as macrophages and neutrophils, to recognize and engulf the pathogens more effectively. This process is crucial for the efficient clearance of infections, as it helps the immune system to target and eliminate harmful microorganisms.

The other options do not accurately describe the functions of acute phase reactants. For instance, reducing blood vessel permeability is more associated with different mediators in inflammation, while inhibiting immune responses runs contrary to the general purpose of acute phase reactants, which is to bolster the immune response. Increasing the number of leukocytes is a separate aspect of immune response regulation and is often more related to cytokine activity rather than the direct function of acute phase reactants themselves.