title: Influence of alginic acid and fucoidan on the immune responses of head kidney leukocytes in cod.
abstract: The present study investigated the immunomodulatory activities of alginic acid and fucoidan, both derived from brown seaweeds, on selected cellular immune responses and antibacterial activity of head kidney (HK) leukocytes of cod, Gadus morhua. Primary cultures of HK leukocytes were incubated with either 10 or 100 μg ml⁻¹ of the substances and the effects on respiratory burst, cellular proliferation, acid and alkaline phosphatase activity and cellular myeloperoxidase were measured at 3- and 24-h post-incubation. The antibacterial activity of the supernatants collected from the cell cultures incubated with 100 μg ml⁻¹ of the substances were tested against Vibrio anguillarum and Aeromonas salmonicida. Respiratory burst was significantly elevated in cells incubated with either alginic acid or fucoidan in a dose-dependent manner. Incubation with a higher dose of alginic acid and fucoidan resulted in lower cellular proliferation at 3- and 24-h, respectively. Both acid and alkaline phosphatase activities of HK leukocytes were not significantly modulated, except for a slight elevation of acid phosphatase in cells incubated with 100 μg ml⁻¹ of alginic acid for 24-h. Fucoidan, but not alginic acid significantly increased cellular myeloperoxidase activity at a concentration of 100 μg ml⁻¹. The growth of the bacteria in both the treated and control supernatants was significantly lower than what was observed in the bacterial culture medium. However, the supernatants from the treated cells had significantly higher bacterial growth compared with supernatants of the control cells. Taken together, these results showed that at the tested concentrations, both alginic acid and fucoidan are able to differentially stimulate some cellular immune responses of cod HK leukocytes in vitro and the respiratory burst activity was significantly stimulated by these brown algal derivatives. These substances could be tested as potential immunostimulants in future in vivo studies.
authors.affiliation: Aquatic Animal Health Research Group, Faculty of Biosciences and Aquaculture, University of Nordland, Bodø 8049, Norway. cmacaipang@yahoo.com
authors.forename: Christopher Marlowe A
authors.initials: CM
authors.lastname: Caipang
authors.forename: Carlo C
authors.initials: CC
authors.lastname: Lazado
authors.forename: Ingvild
authors.initials: I
authors.lastname: Berg
authors.forename: Monica F
authors.initials: MF
authors.lastname: Brinchmann
authors.forename: Viswanath
authors.initials: V
authors.lastname: Kiron
mesh_terms: D048409:Aeromonas salmonicida / Q000187:drug effects; D000464:Alginates / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D048389:Gadus morhua / Q000502:physiology*; D020723:Glucuronic Acid / Q000008:administration & dosage / Q000494:pharmacology; D060226:Head Kidney / Q000166:cytology*; D006490:Hemostatics / Q000008:administration & dosage / Q000494:pharmacology; D006603:Hexuronic Acids / Q000008:administration & dosage / Q000494:pharmacology; D007111:Immunity, Cellular / Q000187:drug effects; D007962:Leukocytes / Q000187:drug effects* / Q000502:physiology*; D011134:Polysaccharides / Q000494:pharmacology*; D013997:Time Factors; D014733:Vibrio / Q000187:drug effects
chemical_list: D000464:Alginates; D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D006490:Hemostatics; D006603:Hexuronic Acids; D011134:Polysaccharides; D020723:Glucuronic Acid; C007789:fucoidan