[Concentration-functional interrelationships in the human alternative complement activation pathway].

The dependence of the rate of human complement mediated lysis of rabbit erythrocytes on concentrations of factors B and D of the alternative pathway is characterized by saturation kinetics. At low B and D concentrations no lysis occurs until certain "threshold" concentrations of the respective factor are reached. The type of dependence of the hemolysis rates on the C3 concentration is wavelike, i.e., at definite C3 concentrations the erythrocyte lysis is inhibited. It has been supposed that C3 not only mediates the complement-dependent hemolysis but also plays a prominent role in the self-regulation of this process.