Inherited c'2 deficiency in man: lack of immunochemically detectable c'2 protein in serums from deficient individuals.

Monospecific antiserum to highly purified second component of human complement (C'2) was used to show the absence of the protein from the serums of four persons homozygous for a hereditary deficiency of second-component activity. Serum from an individual heterozygous for the deficiency contained a reduced amount of this protein as compared to the concentration in normal serum. These observations indicate that genetic deficiency of this component is due to failure of synthesis of normal amounts of the protein rather than to synthesis of an antigenically related, hemolytically inactive analog of C'2.