K. Stensvag et al., IN-VITRO DEGRADATION OF AEROMONAS-SALMONICIDA AND LIMULUS-POLYPHEMUS HEMOCYANIN BY ATLANTIC SALMON, SALMO-SALAR L MACROPHAGES, Fish & shellfish immunology, 5(6), 1995, pp. 427-439
Cultivated Atlantic salmon head kidney macrophages endocytosed and dig
ested iodinated formaldehyde-fixed Aeromonas salmonicida antigens effe
ctively. The degradation was time-dependent as demonstrated by increas
ed acid soluble radioactivity obtained in macrophage media with time a
fter the addition of antigens. Gel chromatography of the degraded mate
rial revealed a peak of radioactivity corresponding to molecular weigh
ts between 1000 and 6500 Da. In vitro degradation of Limulus polyphemu
s hemocyanin (LPH) adsorbed to mineral particles was less efficient co
mpared to the degradation of whole bacterial cells, whereas degradatio
n of soluble LPH was negligible. There were no significant differences
in the rate of processing at 4 (6), 12 and 18 degrees C. Inhibition s
tudies using ammonium chloride, a substance that raises the pH of endo
somes and lysosomes, showed decreased intracellular degradation of A.
salmonicida in a dose-dependent manner. Monensin, a substance reported
to block receptor-mediated phagocytosis, very effectively reduced the
extent of processing whereas leupeptin and pepstatin, specific inhibi
tors of the major classes of cysteine and aspartic proteinases respect
ively, only slightly affected the processing. (C) 1995 Academic Press
Limited