Lymphocyte surface marker genes in fugu

At present, much of the fish adaptive immune system remains unknown due to the paucity of marker-specific reagents (e.g. antibodies) to identify immune cells. The genomic sequence of Takifugu rubripes (fugu) represents an important resource to facilitate the identification of lymphocyte-related genes. Here, we review the recent works on B-lymphocyte markers, the heavy (H) chains of IgM and IgD, and Ig light chain, and T-cell marker gene homologues, CD3ε, CD3γ/δ, CD4, and CD8α in a single fish species, fugu. Expressions of these B- and T-lymphocyte markers homologues in peripheral blood leukocytes and other lymphoid tissues of fugu suggest that these molecules in fish would be available as lymphocyte markers. These findings will lead us to develop reliable reagents for the identification of lymphocyte subpopulations. Fugu holds great promise as one of the model organisms for studies of development and evolution of adaptive and innate immunity in vertebrates.