Opsonization resulting from the complement cascade is:

• A. the process by which pathogens are coated with complement proteins to enhance phagocytosis
• B. the direct lysis of pathogens by membrane attack complex formation
• C. the recruitment of neutrophils to the site of infection
• D. the activation of B cells to produce antibodies

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the term 'opsonization' in the context of the immune system. Opsonization is a process that enhances the ability of phagocytes to recognize and engulf pathogens.
2. Step 2: Recognize that the complement cascade is a series of protein activations that help defend against infections, and one of its roles is to tag pathogens for destruction.
3. Step 3: Identify that during opsonization, complement proteins (such as C3b) bind to the surface of pathogens, effectively 'coating' them.
4. Step 4: This coating acts as a signal to phagocytic cells like macrophages and neutrophils, making it easier for these cells to attach to and ingest the pathogens.
5. Step 5: Differentiate opsonization from other complement functions such as direct lysis (via membrane attack complex), recruitment of immune cells, or activation of B cells, which are distinct processes.