Which serum protein stabilizes the C3 convertase in the complement activation pathway initiated

Which serum protein stabilizes the C3 convertase in the complement activation pathway initiated

Which serum protein stabilizes the C3 convertase in the complement activation pathway initiated by cell wall components of pathogens?

A. C1q

B. C4b

C. Immunoglobulin M

D. Mannose-binding lectin

E. Properdin

Answer: E

Explanation: Properdin (factor P) is a serum protein that stabilizes the alternative pathway C3 convertase (C3bBb), preventing its dissociation and enhancing complement activation against pathogens with cell wall components.