What is the consequence of C3 cleavage into C3a and C3b?

The cleavage of complement component C3 into C3a and C3b plays a crucial role in the activation of immune responses. When C3 is cleaved, C3a acts as an anaphylatoxin, which significantly contributes to the inflammatory response by attracting immune cells such as neutrophils and macrophages to the site of infection or injury. This process enhances the recruitment and activation of these immune cells, leading to a stronger and more effective immune response against pathogens.

On the other hand, C3b binds to the surface of pathogens, marking them for opsonization—a process that enhances phagocytosis by immune cells. The presence of C3b on pathogens helps immune cells recognize and eliminate them more efficiently. Overall, the cleavage of C3 into its active fragments is pivotal for both inflammatory signaling and opsonization, underscoring its importance in the initiation and reinforcement of immune responses.