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PubMed1993

[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.

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PubMedDate not supplied

[Modification of proteolytic complement cascade after treatment with exogenous heparin].

The influence of heparin therapeutic concentrations (0.25-10 U/ml) on the kinetic indices of human serum complement activity has been studied. An acceleration of complement-dependent lysis of rabbit erythrocytes via alternative complement pathway was found at low (0.25-0.5 U/ml) heparin concentrations and complement inhibition at higher (5-10 U/ml) concentration. The alternative pathway inhibition was revealed mainly by lag-period elongation of the hemolysis. Heparin in the concentrations more then 1 U/ml caused dose-dependent lowering of sheep erythrocytes hemolysis rate accompanied with reciprocal elevation of complement hemolytical capacity, which shows more "economical" consumption of complement components at heparin presence. The identical effect was observed in sera, deficient in factor D of alternative pathway of complement activation. This can be an evidence of the prevailing heparin inhibition of the classical pathway.

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