CARBOHYDRATE AND LECTIN INTERACTIONS WITH EDWARDSIELLA-ICTALURI AND CHANNEL CATFISH, ICTALURUS-PUNCTATUS (RAFINESQUE), ANTERIOR KIDNEY LEUKOCYTES AND HEPATOCYTES

Seven isolates of Edwardsiella ictaluri were evaluated for channel cat fish red blood cell and neutrophil agglutination properties and reacti vity with lectins and carbohydrates. All isolates were agglutinated by lectin derived from Ricinus communis and the intensity of the aggluti nation reaction could be lessened or abrogated by premixing the lectin derived from Ricinus communis with beta-D-galactose or alpha-L-fucose . Edwardsiella ictaluri isolates also sedimented much more rapidly whe n mixed with lectin derived from Ricinus communis than when mixed with other lectins. Premixing Ricinus communis with beta-D-galactose had t he greatest effect on slowing the rate of sedimentation. Two out of th e seven E. ictaluri isolates were capable of agglutinating channel cat fish red blood cells and anterior kidney neutrophils, and this aggluti nation could be prevented by the addition of beta-D-mannose. Likewise, the per cent phagocytosis of E. ictaluri isolate 1389 (the most inten se neutrophil agglutinator) could be dramatically reduced by the inclu sion of mannose in the assay,mixture. Anterior kidney leucocytes and h epatocytes primarily reacted with lectins derived from Canavalia ensif ormis, Ricinus communis and Triticum vulgaris. The presence on channel catfish cells of carbohydrate-lectin receptors similar in function to those found on mammalian cells and the reaction of E. ictaluri with s pecific lectins suggest that bacterial clearance and lectinophagocytos is may occur in a similar manner in catfish to that in mammals.