EFFECT OF IN-VITRO CADMIUM EXPOSURE ON NATURAL-KILLER (NK) CELLS OF CATFISH, ICTALURUS-MELAS

The effect of in vitro cadmium exposure on catfish natural killer (NK) cells was investigated. Purification of NK cells by nylon-wool column s and density gradient centrifugation indicated that they were a popul ation of nylon-wool adherent cells. Subsequently NK cells were separat ed only by density gradient centrifugation, where these cells band at the 43/45.5% Percoll interface. In some cytotoxicity assays, catfish N K cells were exposed to 5, 10, 30 and 50 mu M cadmium (CdCl2); 10 mu l of Cd solutions were added to NK cells simultaneously with the target cells. In vitro, 5 mu M Cd inhibited the ability of catfish NK cells to kill the human erythroleukemic cell line K-562. In the presence of 10 mu M Cd, the antibody-independent cytotoxic activity was totally su ppressed. (C) 1996 Academic Press Limited