Phylogeny of complement components in non-human primates

Abstract

The antigenic properties and functional activities of complement components were analyzed in primates to determine their relative evolutionary development. The sera of eight different sub-human primate species were examined by double diffusion in agar and compared to a pool of human serum with rabbit and goat antisera to human complement components Clq, Cls, C4, C2 C3, C5, C6, C8, C9, properdin, factor B (B), and C1 inhibitor. There are no apparent antigenic differences in complement proteins between man and the apes except for C1q. Old world monkeys are antigenically deficient in Clq,C1s, C9, and variably deficient in C4, C3, and C8. New World monkeys are antigenically deficient in all components (measured) except C5, C6, and properdin factor B. Prosimians are antigenically deficient in all components. Functional analyses of complement components showed similar levels in man and primates, except in prosimians. There is a dissociation between hemolytic assays and antigenic analyses, suggesting that functional sites may be separate from antigenic sites.