C3 and age-related macular degeneration: Most importantly, AMD-derived drusen also contain almost all of the complement proteins, including regulatory proteins (CFH, vitronectin, and clusterin), the products of CS activation and degradation (C1q, C3, C3a, C3b, and C5a), and members of the terminal CS pathway comprising the MAC components (i.e., 5, 6, 8 (α, β, and γ), and 9) in the separated and complex form [14, 69].