CHANNEL CATFISH, ICTALURUS-PUNCTATUS RAFINESQUE, NEUTROPHIL ADHESION TO SELECTED EXTRACELLULAR-MATRIX PROTEINS, LIPOPOLYSACCHARIDE, AND CATFISH SERUM

Adhesion of leukocytes to endothelium and extracellular matrix protein s is an important step in the inflammatory process. Therefore, the adh esion of channel catfish neutrophils to a surface coated with extracel lular matrix proteins, LPS, and non-immune catfish serum was evaluated . Stimulation of neutrophils with phorbol dibutyrate (PDBU) resulted i n at least two-fold increases in cellular adhesion to all substrates t ested except laminin. When EDTA was included during or after PDBU PDBU stimulation, neutrophil adhesion to ECM fibrinogen and LPS coated sur faces was EDTA reduced to the level of unstimulated LPS neutrophils or to 50-60% of that for stimulated neutrophils. Similarly, EDTA and Ca2 +/Mg2+ deficient medium reduced homotypic aggregation of PDBU stimulat ed neutrophils to background levels. Adhesion of stimulated neutrophil s to fibrinogen coated surfaces was inhibited 44, 33, and 50% when sol uble fibrinogen, fibronectin, and serum, respectively, were used to bl ock the adhesion assay. The tripeptide integrin adhesion recognition s equence, Arg-Gly-Asp (RGD), caused 83% reduction and the fibrinogen-bi nding inhibitor protein caused 10% reduction in binding of stimulated neutrophils to fibrinogen coated surfaces, Two hexapeptides tested did not reduce neutrophil adhesion to fibrinogen. The binding of channel catfish neutrophils to the matrices used in the present study is sugge stive that integrin mediated adhesion occurs during biological and pat hological processes of teleosts. Copyright (C) 1996 Elsevier Science L td.