Heterogeneity in electrophoretic mobility of C3-derived molecules expressing D but not C-epitopes following in vivo activation of the complement system.

Four different populations of C3-derived molecules expressing D but not C epitopes were identified following in vivo activation of the complement system. The four molecular forms, differing in electrophoretic migration velocity, were assigned the nos. 1, 2, 3 and 4 after decreasing electrophoretic mobility. Analysis of the time-dependent changes in the relative concentration of the different molecular forms demonstrated an increase in the plasma concentration of population 4 and a decrease of populations 2 and 3, whereas form 1 remained rather constant after acute activation of the complement system.