C4

The Scientific & Social Program: Vth ISDCI Congress

POTENTIATION OF THE TROUT PHAGOCYTE RESPIRATORY BURST. *I.S. Galvan & C.J. Bayne. Department of Zoology, Oregon State University, Corvallis, OR 97331, USA.

When rainbow trout pronephric leukocytes are explanted into culture, their ability to produce phorbol ester-stimulated superoxide anions increases over time. This change occurs in a subpopulation strongly enriched for neutrophils and macrophages by density gradient centrifugation. When this population is incubated for 24 hours in the presence of 100ug/ml LPS, the number of esterase-positive, plastic-adherent cells increases significantly over controls. The non-adherent cells from such LPS- treated cultures yield an enhanced respiratory burst. This priming effect of LPS on the non-adherent population requires the presence of the adherent population. We infer an interaction between the LPS-stimulated trout macrophages and neutrophils which potentiates the respiratory burst of the latter cells.

$53

C5

II~UNOSTJ~FdLATIONOF I~R~OACTIVEPEFTIDETOFISH LEUCOCYTES. *T. Kitao & T. Yoshida. Department of Fisheries, Faculty of Agricultuere, Miyazaki University, Miyazaki 889-21, JAPAN.

An immunoactive peptide, FK-565, has been demonstrated by Kltao et al . (1986 and 1987) to st imulate phagocytic a c t i v i t y , humoral antibody production and protec t ion when given to rainbow t rout one day before challenge with heromonas salmonlclda. In th is experiments we inves t iga te the e f fec t of FK-565 on chemiluminescence (CL) and spreading a c t i v i t y of rainbow t rout leucocytes under the in v i t ro condit ion. Furthermore, we report the immunostimulatlon of FK-565 to antibody producing ce l l s and humoral antibody release when administrated with a bacter in to ye l lowta i l .

Peripheral and spleen leucocytes obtained from rainbow t rout were cul tured with FK-565 in d i f f e ren t concentrat ions (0; 20 and 40 ug/ml) for 20 hr at 11"c. After cu l t iva t ion , the ce l l s were harvested and the CL assays were car r ied out by using zymosan as a st imulant. Spreading assays were performed by using glass adherent leucocytes cul tures with FK-565. Furthermore, the immnostlmulation of FK-565 to antibody producing ce l l s and humoral antibody t l t e r s were checked during immunization regimes in ye l lowta i l when the bacter ln was mixed with the FK-565.

We found that FK-565 as immunoactlve peptide successfuly ac t iva ted CL response of both peripheral and spleen leucocytes. Furthermore i t increased the spreading a c t i v i t y of spleen glass adherent leucocytes. The numbers of antibody producing ce l l s and t l t e r s of humoral antibody in ye l lowta i l were elevated.