Monoclonal antibodies reactive with serum IgM and leukocytes from Atlantic salmon (Salmo salarL.)

Monoclonal antibodies (MAbs) reactive with salmon serum IgM and blood leukocytes (C7G7, G2H3, C4B6, G6F2, D8B3) and one (E3D9) reacting specifically with polymorphonuclear cells have been produced. Two MAbs, C7G7 and G2H3, were highly reactive with serum IgM in ELISA and immunoblots, and G6F2, D8B3 and C4B6 showed highest reactivity in ELISA using leukocytes as antigen. Immunoblots showed that the IgM positive MAbs reacted with the heavy chain of salmon IgM. Deglycosylation of IgM showed that the C7G7 MAb recognised a carbohydrate epitope, while G2H3 recognised a protein epitope. The C4B6, G6F2 and D8B3 MAbs most probably bound to carbohydrate epitopes. The MAb E3D9 was not reactive with serum IgM, and showed low reactivity in the leukocyte ELISA. Bound to immunomagnetic beads, E3D9 was shown to bind polymorphonuclear leukocytes, judged from the cell morphology of the immunoabsorbed cells.