ISOLATION AND CHARACTERIZATION OF THIRD COMPONENT OF RAT COMPLEMENT

Google Scholar
  • 1 January 1979
    • journal article
    • research article
    • Vol. 36  (1) , 63-70
Abstract
The third component of complement (C3) from rat plasma was isolated by precipitation with polyethyleneglycol in the presence of benzamidine, followed by chromatography of the precipitate on CM-cellulose, hydroxyapatite and QAE [quaternary aminoethyl] A50-Sephadex, and gel filtration on Sephadex G-200 superfine. C3 was isolated in its native form, as assessed by its specific functional activity and its immunoelectrophoretic mobility. The recovery of C3 was 18-26%, and the final material was homogenous on SDS-PAGE [sodium dodecyl sulfate-polyacrylamide gel electrophoresis] analysis. Rat C3 has an apparent MW of 187,000 and is composed of 2 non-identical disulfide linked polypeptide chains of 123,000 and 76,000. A monospecific antiserum against rat C3 was produced by immunization of rabbits with purified C3. Zymosan treatment of rat serum resulted in cleavage of C3 and in the appearance of a component with a greater mobility during immunoelectrophoresis. The plasma concentration of rat C3 in Wistar rats was 581 .+-. 49 .mu.g/ml (mean .+-. 1 SD). Interaction of highly purified rat C3 with purified human components B[factor B], .hivin.D [activated factor D], and .hivin.P [activated properdin] resulted in the formation of a C3 convertase suggesting compatibility between human and rat C3.