Specific cell-mediated immunity in fish

This review describes the fish immune system, focusing on specific cell-med iated immunity. Specific in vivo cell-mediated immune responses have been s hown by allograft rejection, graft-versus-host reaction (GVHR) and delayed hypersensitivity reaction (DTH). Recent in vitro studies also showed specif ic cell-mediated cytotoxicity against allogeneic target cells. These in viv o and in vitro experiments strongly suggest the presence of cytotoxic T cel ls in fishes. Also described are current studies on shark and trout MHC cla ss I polymorphism and function that demonstrate strong similarities between fish and mammals. (C) 1999 Elsevier Science B.V. All rights reserved.