BINDING OF IMMUNE-COMPLEXES TO ATLANTIC SALMON PERIPHERAL-BLOOD LEUKOCYTES

The ability of peripheral blood leucocytes (PBL) of Atlantic salmon to bind immune complexes in an antibody-dependent fashion was investigat ed. Immune complexes were labelled with fluorescein isothiocyanate and binding of these complexes to isolated PBL was determined by flow cyt ometry. The data show that a high proportion (up to 65%) of PBL were c apable of binding immune complexes, and this binding did not occur whe n immune serum was replaced with normal serum. The presence of fresh n ormal serum inhibited or abrogated immune complex-binding of PBL. This is the first report of high levels of immune complex receptors on leu cocytes in fish, and the dependence of complex binding on the presence of antibody suggests that these receptors may be similar to Fc recept ors which are widely distributed on immunocytes of mammals. (C) 1998 E lsevier Science Ltd. All rights reserved.