Effect of environmental temperature on in vitro cell-mediated cytotoxicity (CMC) and graft-versus-host reaction (GVHR) in ginbuna crucian carp ( Carassius auratus langsdorfii)

The effect of temperature (15, 20 and 25 deg C) on the suppression of in vitro cell-mediated cytotoxicity was investigated in clonal, triploid ginbuna crucian carp (S3n) from Lake Suwa, Nagano Prefecture, Japan sensitized by scale grafts from tetraploid hybrids (S4n) bred by insemination of S3n with goldfish sperm. Sensitized S3n effector cells were separated from blood on Percoll gradients (1.085 g/ml); 82% of separated cells were lymphocytes. Haemoglobin release was detected by tetramethylbenzidine. Injection (i.p.) of sensitized effector PBL from S3n to S4n recipients resulted in graft versus host disease (GVHD) characterized by pale gills, scale protrusion, ascites, haemorrhage and necrosis of the ventral skin, muscle layers and peritoneum. PM findings included peritonitis and intestinal and liver necrosis. Death rate was highest in fish kept at 25 deg C and lowest at 15 deg C. Further work needed to explain these results is discussed