Characterization and properties of an anaphylactic 7S antibody in sheep

Anti-DNP antibody was specifically purified from hyperimmune anti-DNP-BGG sheep antiserum. The antibody was fractionated on DEAE-cellulose. Two components belonging to different immunoglobulin classes were isolated and designated IgS (slow) and IgF (fast) on account of their relative electrophoretic mobility. The molecular size of both antibodies is the same and it is similar to that of human IgG. IgS induces homologous anaphylactic reactions (PCA) and does not fix complement in the classical way. IgF fixes complement and is not anaphylactic for the sheep. The biologic activities of IgS are not destroyed by treatment with 2-mercaptoethanol. The skin sensitization obtained with IgS does not persist more than 2 hr.