INCREASED ADHESION OF CHANNEL CATFISH, ICTALURUS-PUNCTATUS RAFINESQUE, NEUTROPHILS TO SUBSTRATES FOLLOWING STIMULATION WITH PHORBOL ESTER

Using a modification of a minimal shear force adhesion assay, a compar ison was made of stimulated and unstimulated channel catfish neutrophi l adhesion to bovine serum albumin (BSA), concanavalin A (Con A), cold water fish gelatin (F-GN), porcine gelatin (P-GN), lipopolysaccharide (LPS), and channel catfish serum. Significant increases in adhesion we re noted when phorbol dibutyrate (PDBU) stimulated catfish neutrophils were added to microtiter plate wells coated with BSA, P-GN, LPS, and serum. As a comparison, stimulated equine neutrophils were also evalua ted in the assay and displayed significant increases in adhesion to BS A, Con A, P-GN, and LPS. Appreciable blocking of channel catfish neutr ophil adhesion could be accomplished by the addition of homologous sub strate except in the case of Con A and F-GN. Phorbol dibutyrate stimul ated, cytochalasin D-treated catfish neutrophils, as opposed to non-cy tochalasin D-treated cells, always gave the most consistent results in blocking assays. These results support the idea that channel catfish neutrophils, like mammalian neutrophils, increase their adhesive prope rties upon receiving the appropriate stimulus. (C) 1996 Academic Press Limited