An analysis of the serum factors involved in the lysis and agglutination of artificially altered red cells in compatible human serum has been presented. Human sera have been found to vary widely in their capacity to hemolyze a panel of artificially altered red cells.
These differences have been shown to be the result of a multiplicity of more or less specific serum factors for each altered red cell type. These factors have many of the properties commonly associated with classical antibody.
These serum factors are different from complement and properdin.
The range of specificity and the degree of cross reaction for these various serum factors have been analyzed.
These serum factors are important in the consideration of the use of enzyme treated red cells for the detection of incomplete antibodies, and of certain acquired hemolytic states in man.