Attempts at a Quantitative Estimation of the Second Component of Complement

Abstract
Summary: Reagents without detectable second component have been prepared from human, guinea pig and pig complements. The hemolytic power of mixtures of these reagents with human, guinea pig and pig complements has been studied quantitatively. Hemolysis with a given reagent is indicated to be an undetermined function of its content of third component. Values found for second component in several human complements lie within limits previously established by qualitative titrations and, in general, do not differ more than by ±15 per cent from the mean. Variations in the case of guinea pig complement were greater. Discrepancies between values obtained with different reagents may be due to a partially masked anticomplementary property of a given complement-reagent combination or to incomplete mutual equivalence of components of complement from different species.
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