Advances in Intestinal Mucosal Immunoglobulins of Teleost Fish (Review)

Immunoglobulins are globulins with antibody activity or antibody-like structures, and fish were the first vertebrates to develop immunoglobulins. There are three major types of immunoglobulins (IgM, IgD and IgZ) in teleost fish, which play an important role in resisting pathogen infection. For fish, the intestinal tract is not only the place for nutrient digestion but also the largest endocrine organ. The intestinal mucosal barrier system can block pathogenic microorganisms and toxins and is important for immunologic defense. Therefore, the study of the molecular mechanism of fish immunoglobulin in intestinal mucosa is of great significance to the selection of immune prevention strategies for fish diseases. At present, information on the immune system of intestinal mucosa in fish is scarce, and there are still many problems in the function of newly identified antibodies, which need further research. In this study, we have summarized current knowledge about the types, gene structure, biological function, and immune response of immunoglobulins in teleost fish, and intestinal mucosal immune tissue of fish. The scientific questions in this field were also presented according to the progress from the latest research in fish immunology. The aim of present study is to provide a theoretical basis for the study of fish immunology