Synthesize the role of C3 convertase in the activation of immune responses across all three complement pathways.

• A. C3 convertase forms a membrane attack complex in the alternative pathway only.
• B. C3 convertase is unique to the lectin pathway and does not interact with other pathways.
• C. C3 convertase cleaves C3 into C3a and C3b in all pathways, leading to opsonization, cell lysis, and inflammation.
• D. C3 convertase only functions in the classical pathway to recruit antibodies.

Answer: (C)