KP2 Acute phase proteins in trout

Abstracts of the 7th Congress of the ISDCI: Session K

173

KPl

THE ROLE OF INDUCIBLE NITRIC OXIDE SYNTHASE AND NITRIC OXIDE IN THE IMMUNE SYSTEM OF RAINBOW TROUT. Juan J. Camoos-Pkrez’D, K.J. Laing*, Anthony E. Ellis’ and Christopher J. Secombes’. ‘SOAEFD Marine Laboratory, P.O. Box 101, Victoria Road, Aberdeen ABl 1 9DB, Scotland, U.K., and: 9 Department of Zoology, University of Aberdeen, Aberdeen AB24 2TZ, Scotland, U.K

Recent studies have shown that in addition to the generation of bactericidal free radicals, fish phagocytes can produce nitrogen radicals such as nitric oxide (NO). NO production is dependent upon an inducible enzyme, nitric oxide synthase (iNOS), and we have obtained a partial sequence for this enzyme in trout and goldfish, that show 71% and 75% amino acid homology with human iNOS. In viva and in vitro studies have shown that trout iNOS is indeed inducible and is expressed in macrophages following stimulation with Gram negative bacteria or LPS. Serum nitrite levels can be used to monitor NO production in vivo, determined via the Griessreaction. After challenge of trout with 4 different strains of Renibacterium salmoninarum, a relatively higher amount of serum nitrite was found in fish challenged with the most virulent strain. Direct measurement of NO production by head kidney macrophages activated in vitro with different combinations of stimulators was also studied. The role of NO in bactericidal activity was assessedusing cell-free assaysof NO production. S-nitroso-N-acetyl-penicillamine (SNAP), an NO donor, and 3-morpholinosydnonimine-N-ethyl-carbamide (SIN-l), an 0; and NO generator which spontaneously produces the highly reactive peroxynitrite, were used. The results of thes#eexperiments are presented and discussed. KP2

ACUTE

PHASE

m 9773 I ‘.,

& Christopher

PROTEINS J. Bayne,

IN TROUT

Department

of Zoology,

Oregon

State University,

Corvallis,

OR

The acute phase response (APR) is an early reqxmse of the innate immune s stem to an Mammatory wt. Acute phase proteins (APP) are part of this responseand tlLt ‘c p&ktionintheliverisinducedbycytolcks. TheAPRhasbeenwellckac&rizedin mammalsbutitisuncleartowhatdegAesekostsmountasimilatnspn\Je. lnaneffortto charactenatheAPPoftherainbowtroutwehaveused”fandem~lmmuncF fn#nthcsamefishbefaeand