[Effect of medicinal preparations on the complement: inhibition of subcomponent C1q binding to a target]

A method is developed for determining the inhibition constants of substances capable of acting on the complement system at the stage of target recognition (immune complexes) by the first component of the complement (and, hence, blocking activation of the classical pathway of the complement). The ability of some drugs to inhibit the binding of subcomponent C1q to a target has been studied. It is shown that some drugs possess a pronounced ability to block the complement activation. The inhibition constants are compared to the therapeutic dozes of drugs. Some of the investigated preparations (suramin, sodium deoxiribonucleate, curcumin, heparin, sulfetron, guttalax, lysozyme) upon administration can present in the blood flow in concentrations capable of blocking the complement. The method is useful in the search for preparations capable of inhibiting the complement and in the study of side effects of medicinal preparations.