title: Specific antigen-binding molecules in normal serum. A quest for circulating receptors.
abstract: Molecules (I) in the IgM fraction of normal serum compete with specific antibody for a single determinant on a macromolecule. Following immunization, the levels of I fall as antibody titer rises, but they later increase again during the decline of antibody. These findings are discussed in light of recent studies regarding soluble antigen-specific factors.
mesh_terms: D000818:Animals; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D000939:Epitopes; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D046911:Macromolecular Substances; D011817:Rabbits; D011947:Receptors, Antigen, B-Cell; D001616:beta-Galactosidase / Q000276:immunology
chemical_list: D000939:Epitopes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D046911:Macromolecular Substances; D011947:Receptors, Antigen, B-Cell; D001616:beta-Galactosidase