Production of Monoclonal Antibodies (Mabs) Against Surface Antigens on Israeli Carp Lymphocytes and Their Applications

In fish both humoral and cell mediated immune responses have been reported whereas antibodies recognizing specific cellular populations have not yet been developed except for ones recognizing surface Ig molecules on B lymphocytes. Our aim was to develop and characterize monoclonal antibodies (Mabs) specific for the immune-related cells. Mabs were produced by fusion of myeloma cells (SP2/0) with Balb/c mouse spleen cells previously sensitized against Israeli carp (I. carp) kidney mononuclear cells. We obtained 44 Mabs positively reacting with I. carp kidney mononuclear cells and partially characterized 7 Mabs in the morphological and mitogen-based proliferative aspects. Fluorescence-activated cell sorter (FACS) analysis against I. carp kidney cells by using 7 different Mabs showed 80.3% for ICK 17-4, 65.1% for ICK 2-3, 64.1% for ICK 25-1, 67.5% for lCK 22-1, 70.8% for ICK 16-2, 76.8% for ICK 13-2, 79.7% for ICK II-I. Panning method was used for the isolation of Mabs specific mononuclear carp spleen cells followed by Wright's stain. The stained cell populations were identified as monocytes (ICK 17-4, ICK 2-3, ICK 25-1, ICK 22-1 and ICK 16-2), lymphocytes (ICK 11-1), and a mixed cell population of monocytes and lymphocytes (ICK 13-2). In cell proliferation assay, monocytes purified by ICK 17-4, 2-3 and 22-1 efficiently responded to Con A and PHA, while ones separated by ICK 25-1 did not react with any mitogens. Lymphocytes isolated by ICK 11-1, though it is not known whether they are T or B cells, were more responsive to Con A than PHA or LPS, suggesting that fish immune cells are somewhat different from mammalian cells in responding to mammalian T or B cell mitogens.