Inhibition of rainbow trout phagocyte responsiveness tohuman tumor necrosis factor a(hTNFa) with monoclonal antibodies to the hTNFa 55 kDa receptor

Human tumor necrosis factor a (hTNFa) was found to increase rainbow trout macrophage respiratory burst activity and neutrophil migration. The increase in respiratory burst activity was inhibited by preincubation of the hTNFa with a soluble 55 kDa hTNFa receptor (TNF-Rl). Preincubation of the phagocytes with monoclonal antibodies (MAbs) to the TNF-R1 was found to ablate their responsiveness to hTNFa, dependent on the concentration of MAbs used. These findings are discussed with a view towards using such MAbs to elucidate the possible secretion of TNF by fish leucocytes.