TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Lectin Enhancement Of Anti-Aeromonas salmonicida Activity Of Atlantic Salmon Macrophages Christopher A. Ottinger2, Stewart C. Johnson1, K. Vanya Ewart1, Neil W. Ross1 1National Research Council of Canada, Institute for Marine Biosciences, Halifax, Nova Scotia, B3H 3Z1, Canada; 2National Fish Health Research Laboratory, Kearneysville, West Virginia, USA, 25430 Lectins are sugar-binding proteins that have been postulated to play a major role in the innate immune system of invertebrates and vertebrates. The ability of a purified mannose-binding lectin from Atlantic salmon serum to modulate macrophage responses was assessed in vitro. In its native form this lectin exists as disulphide-linked multimers of an Mr 17,000 subunit. Due to its mannose-rich surface and its relevance as a salmonid pathogen, wild-type Aeromonas salmonicida was selected as a target for the functional characterization studies of this lectin. Binding of the lectin in the absence of other factors did not significantly reduce (P > 0.05) the viability of A. salmonicida. However, binding of the lectin to A. salmonicida did result in significant (P < 0.05) dose-dependent increases in phagocytosis, respiratory burst and bactericidal activity. The structure and activity of this lectin are similar to that of mammalian mannose-binding lectins, which are known to play a pivotal role in innate immunity. This lectin may be especially important when fish are exposed to gram-negative bacteria such as A. salmonicida. If it is determined that the production of this lectin can be induced, there may be potential for artificially stimulating its production to provide protection against important bacterial pathogens of Atlantic salmon. In circumstances where vaccination and/or chemotherapy are not feasible, such a technique would be very valuable.   Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page