University of Central Florida (UCF) PCB3233 Immunology Practice Exam 1

C3b is a crucial component of the immune system, particularly in the context of the complement system. While C3b plays a significant role in opsonization, which enhances the recognition and clearance of pathogens by immune cells, it cannot neutralize pathogens on its own. Neutralization of pathogens typically involves the binding of antibodies to pathogens, which directly inactivates them or prevents their interaction with host cells.

C3b functions primarily by opsonizing pathogens, marking them for destruction by phagocytes. In this way, its activity is more about facilitating the immune response rather than neutralizing pathogens independently. Therefore, stating that C3b alone can neutralize pathogens is incorrect, confirming that the answer is indeed false.