Isolation and partial characterization of immunoglobulins of goldfish (Carassius auratus) and carp (Cyprinus carpio).

Two related species of teleost fishes, the goldfish () and the carp (), responded to injection of protein antigens by producing antibodies which resembled the γM immunoglobulins of other vertebrates in size and polypeptide chain structure. No other immunoglobulin classes were observed in these fish. Since the ancestors of the teleosts diverged from those of the tetrapods over 300 million years ago, the present results are consistent with the hypothesis that light chains and μ-type heavy chains emerged early in vertebrate evolution.