Biosynthesis of the second (C2) and fourth (C4) components of complement in vitro by tissues isolated from guinea-pigs with genetically determined C4 deficiency

Abstract

Tissues and cells isolated from guinea-pigs homozygous for a genetically determined deficiency of the fourth (C4) component of complement failed to synthesize C4 and synthesized C2 at a rate approximately 40 per cent of normal. These abnormalities in the biosynthesis of C2 and C4 persisted up to four weeks in tissue culture. Tissues and cells from heterozygous C4-deficient animals produced C4 at a rate intermediate between normal and that of the homozygous deficient. These observations demonstrate that the reduced serum concentrations of C2 and C4 in C4-deficient guinea-pigs can be accounted for by abnormalities in biosynthesis and are probably not the result of hypercatabolism of these proteins.