Increased adhesion of channel catfish,Ictalurus punctatusRafinesque, neutrophils to substrates following stimulation with phorbol ester

Using a modification of a minimal shear force adhesion assay, a comparison was made of stimulated and unstimulated channel catfish neutrophil adhesion to bovine serum albumin (BSA), concanavalin A (Con A), coldwater fish gelatin (F-GN), porcine gelatin (P-GN), lipopolysaccharide (LPS), and channel catfish serum. Significant increases in adhesion were 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 evaluated in the assay and displayed significant increases in adhesion to BSA, Con A, P-GN, and LPS. Appreciable blocking of channel catfish neutrophil adhesion could be accomplished by the addition of homologous substrate except in the case of Con A and F-GN. Phorbol dibutyrate stimulated, cytochalasin D-treated catfish neutrophils, as opposed to non-cytochalasin 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 properties upon receiving the appropriate stimulus.