Developmental Aspects of Immunoglobulins and Antibodies

This short review discusses the evolution of the immunoglobulins and the development of the diversity of antibodies. Birds and mammals represent two lines of development having divided more than 300 million years ago. In the immunoglobulins and antibody-systems there are many similarities which, however, are based on analogies. In this sense the dominant humoral type of immunoglobulin is IgY in birds and opposed to IgG in the mammals. Also, the mechanisms differ which lead to the diversity of antibodies. In mammals predominantly recombination of gen-segments and somatic mutations lead to this diversity, in birds gen-conversion shows a greater significance. In this way comparable results are produced through different structures or mechanisms.