Genetic polymorphism of a serum euglobulin of chickens which binds to antigen-antibody complexes.

Binding of a euglobulin from normal chicken serum to precipitating HSA anti-HSA complexes has been demonstrated. The binding appeared specific for the Fc-fragment of chicken antibody since it was not detected with rabbit Ag-Ab complexes. Two allelic allotypic markers of the euglobulin under genetic control from one locus (E-1) were found in chickens from two inbred strains. E-1 alleles segregated independently from those controlled by the B (major histocompatibility), M-1 and G-1 (Ig allotype) loci. Partially purified E-1 had a sedimentation coefficient of 15.6 S. and beta-globulin electrophoretic mobility.