Plasma therapy of primary rat mammary carcinoma: dependence of consumption of C3 during absorption of plasma with sepharose derivatives on the anticoagulant.
A previous study demonstrated inhibition of growth of primary rat mammary carcinomas after infusion of tumor-bearer plasma absorbed against Sepharose derivatives. In this report we have quantitated changes in individual complement components that occur during absorption of rat plasma with Sepharose derivatives and defined optimal conditions for consumption of the third component of complement (C3) (other complement components defined similarly). The concentration of functionally active C1 to C9 was measured before and after absorption in plasmas from both normal rats and rats with mammary tumors. C3 activity in plasmas from normal and tumor-bearing rats was reduced (consumed) during absorption under appropriate conditions with Sepharose 4B, inactivated CNBr Sepharose, or Protein A-Sepharose. The concentration of functionally active C1 and C4 did not decrease significantly during absorption with Sepharose derivatives. Consumption of C3 in rat plasma was influenced by the anticoagulant and by the time and temperature of incubation with Sepharose derivative. C3 consumption in rat plasma anticoagulated with acid citrate dextrose solution was variable; addition of Mg2+ (5 mM) to plasma anticoagulated with acid citrate dextrose solution augmented C3 consumption. There was no C3 consumption in plasma anticoagulated with ethylenedinitrilotetraacetic acid (a chelator of calcium and magnesium). In contrast, this reduction was observed in plasma anticoagulated with [(ethylenebis(oxyethylenenitrilo)]tetraacetic acid (a chelator of calcium). The results demonstrate optimal conditions for activation of the alternative pathway of complement during absorption of rat plasma with Sepharose derivatives and suggest in vivo experiments to define the role of this pathway in inhibition of growth of mammary tumors.