Partial characterization of procomplementary activity of porcine serum and its relationship to the fifth component of complement.

The procomplementary factor (PCF) of porcine serum, a component that enhances the hemolytic activity of guinea pig complement, was purified by precipitation with methanol and then by diethylaminoethyl-cellulose chromatography. The PCF substituted for the 5th complement component (C5) in the complement cascade in tests with functionally purified guinea pig complement components. In contrast to human C5, PCF is heat stable at 56 C.