Nonspecific cytotoxic cells in fish (Ictaluruspunctatus). II. Parameters of target cell lysis and specificity

Abstract Fish nonspecific cytotoxic cells (NCC) lyse various transformed human B-cells (NC-37, P3HR-1) and erythroblastoid cells (K562) as well as mouse YAC-1 and P815 cells. Highest NCC activity was found in the anterior (head) kidney, but spleen cells and peripheral blood leucocytes (PBL) also demonstrated cytolytic abilities. Lysis of chromium-51 labeled target cells occurred rapidly and optimum cytolysis developed at either 16°C or 26°C incubation temperatures. Preincubation at temperatures of 4°C or 37°C for 4 hours reduced NCC cytotoxicity. Although catfish ( Ictalurus punctatus ) are extensively outbred, interfish NCC activities did not significantly vary at the optimum E:T ratios (160). The NCC target antigen specificities were partially determined by cold target inhibition (CTI) studies. Transformed B-cell lines gave homologous and heterologous CTI. YAC-1 and K562 did not produce significant CTI, however. These studies demonstrated the presence of a highly active cytotoxic cell which is widely distributed in fish lymphoreticular tissue. NCC kill divergent kinds of transformed cell types, and the target cell specificity for human transformed B-cells is different from the NCC target cell antigens on other human (K562) and on mouse (YAC-1 and P815) cells.