GENERATION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES AGAINST RAINBOW-TROUT, ONCORHYNCHUS-MYKISS, LEUKOCYTES

Monoclonal antibodies were raised against head kidney macrophages of t he rainbow trout, Oncorhynchus mykiss. Despite the establishment of a significant number of different hybridoma clones, none of these releas ed antibody specific for determinants only found on macrophages. Inste ad, all the monoclonal antibodies generated reacted with lymphocytes, granulocytes, and monocytes/macrophages, although thrombocytes (the pl atelet equivalents in fish) and erythrocytes were nor recognized by th ese antibodies. Western blotting of solubilised macrophages revealed t hat two of the hybridoma lines, designated 21G6 and 21F11, reacted wit h at least five proteins of 80, 104, 110, 140, and >170 kDa. Immunocyt ochemistry was performed on histological sections of trout alimentary canal, gill, liver, spleen, and haemopoietic head kidney using antibod ies from several of the hybridoma lines, and all of these showed a sim ilar pattern of reactivity in each tissue. In the alimentary canal, fo r example, immunoreactive material was found in the eosinophilic granu lar cells, blood vessel margins, mucus in the lumen, and in the column ar epithelial cells. In the gills, epithelial cells and blood vessels also showed intense immunoreactive produces, while in the liver, such reactivity was localised in the sinusoids and adherent macrophages. Bo th the spleen and head kidney had largely homogeneous immunoreactivity . (C) 1997 Elsevier Science Inc.