A SIMPLE METHOD FOR QUANTITATIVE MEASUREMENT OF C3D IN HUMAN-PLASMA

A simple and reliable method for quantitating C3d in human plasma is described. The method rests on the finding that native C3 and its activation/inactivation product C3c bind to concanavalin A [Con-A]; C3d does not. Rocket affinoimmunoelectrophoresis with Con-A Sepharose incorporated into an intermediate gel permits quantitation of free C3d in 2-20 .mu.l aliquots of EDTA-plasma without any manipulation prior to sample application. Using this method, the level of circulating C3d in plasma of 30 healthy donors was usually well below 3% of maximally convertable C3d.