Specific cell-mediated cytotoxicity against an allogeneic target cell line in isogeneic ginbuna crucian carp

Specific cell-mediated cytotoxicity in fish was investigated using both iso-geneic (clonal) ginbuna crucian carp,Carassius auratus langsdorfii, and three cell lines established from the three different clones of this fish. Specific cell-mediated cytotoxicity in ginbuna was induced as a result of intravenous immunisation with an allogenic cell line, but not a syngeneic cell line. As the cytotoxic activity tended to accelerate in proportion to the number of immunisations, specific cytotoxic cells in ginbuna resembled mammalian cytotoxic T lymphocytes (CTL) in some respects. In addition, it was unlikely that antibody-dependent cell-mediated cytotoxicity (ADCC) was involved in the cytotoxicity observed in this study because ADCC activity of unimmunised fish effector cells was not detected using the immunised ginbuna plasma or the supernatant of cultured effector cells from immunised ginbuna. These results demonstrate that specific cell-mediated cytotoxicity is inherent in fish and a set of clonal fish and their cell lines may be useful for further studyin vivoandin vitro.