Influences of Aeromonas salmonicida lipopolysaccharide, prednisolone and water temperature on plasma protein composition in salmonids

To further characterize the putative role of constitutive and inducible pla sma proteins in innate resistance to furunculosis, the present authors comp ared the alterations in profiles of plasma proteins in resistant and suscep tible salmonids, i.e. rainbow trout, Oncorhynchus mykiss (Walbaum), and bro ok trout, Salvelinus fontinalis (Mitchill), respectively Rainbow trout were injected with prednisolone acetate and exposed to higher water temperature (18 degrees C versus 10 degrees C), or injected with purified lipopolysacc haride (LPS) from a virulent strain of Aeromonas salmonicida, and plasma co mponents were examined by two-dimensional polyacrylamide electrophoresis. T wo days after A. salmonicida LPS exposure, rainbow trout had a four- to fiv e-fold increase in concentrations of plasma proteins composed of p48, p19 a nd p16 subunits, and a significant decrease in a 100-kDa protein group. Con sistent elevation or depletion of proteins corresponding to previously repo rted rainbow trout A. salmonicida LPS-binding pentraxins and lectins in pla sma were not observed. Brook trout exposed to A. salmonicida LPS did not ha ve any consistent plasma protein changes. There were no significant alterat ions in major plasma proteins following temperature shock and prednisolone acetate administration in rainbow trout plasma. These studies demonstrate t hat rainbow trout with LPS-induced sterile inflammation have few alteration s in major plasma proteins or LPS-binding proteins, and do not exhibit the spectrum of acute phase changes induced by inflammation in mammals.