Characterization of a genetically identifiable component of complement in mice

The hemolytic properties of the sera of complement positive and complement negative strains of mice were studied. The results suggested that the complement negative sera lacked an activity of complement analagous to C'1 which when present is called hc¹. Certain physical and chemical properties of hc¹ were examined. It was destroyed when serum was heated to 56°C, but was resistant to heating when slightly purified. Hc¹ was still precipitable by specific antiserum after treatment with 8 molar urea, but was no longer hemolytically active. Neither the hemolytic nor precipitating activity of hc¹ was altered by treatment with either 0.1 molar ethylenediamine-tetraacetic acid or 0.1 molar 2-mercaptoethanol. Initial attempts made to purify hc¹ are described.