Incorporation of [14C]-leucine into complement in experimental infection of rats in malnourished stages.

The complement biosynthesis was examined in the first complement response, that is at the stage of elevated complement level 3 days after Staphylococcus aureus infection, since this elevation might play a role in host defence before antibody response. [14C]-leucine was used as a labeled amino acid to examine the de novo synthesis of the complement. In the first complement response, the malnourished rats red with 0.5% protein, both in infection and noninfection groups, showed a significantly higher specificity in newly synthesized complement activity than did the rats in the well-nourished group fed with 18% protein. The infected rats showed much higher rates of de novo synthesis of complement activity than noninfected rats and this effect was more predominant in the malnourished group.