title: Immunosuppression in the infaunal bivalve Scrobicularia plana environmentally exposed to mercury and association with its accumulation.
abstract: This study aimed to test the hypothesis whether mercury (Hg) activates or suppresses inappropriately the immunity of the bivalve Scrobicularia plana inhabiting a Hg contaminated area (Laranjo basin, Ria de Aveiro, Portugal). Immunity endpoints, as well as lipid peroxidation (LPO) as a sign of damage, were evaluated in parallel with total Hg burden. Bivalves from both moderately (MO) and highly (HI) contaminated sites displayed higher haemolymph Hg load and reduced plasma agglutination. Increased haemocytes density and decreased phagocytosis were observed at HI, whereas increased oxidative burst activity (OBA) was observed at MO, pointing out that the immunotoxicity is a result of Hg direct contact involving no ROS intervention. OBA observed at MO was concomitantly associated to peroxidative damage as depicted by LPO increase in haemocytes and haemolymph plasma. Thus, S. plana can be suggested as a suitable bioindicator of metal pollution in coastal areas on the basis of Hg bioaccumulation and immunotoxicity responses.
authors.affiliation: CESAM & Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. ahmadr@ua.pt
authors.forename: Iqbal
authors.initials: I
authors.lastname: Ahmad
authors.forename: João P
authors.initials: JP
authors.lastname: Coelho
authors.forename: Iram
authors.initials: I
authors.lastname: Mohmood
authors.forename: Mário
authors.initials: M
authors.lastname: Pacheco
authors.forename: Maria A
authors.initials: MA
authors.lastname: Santos
authors.forename: Armando C
authors.initials: AC
authors.lastname: Duarte
authors.forename: Eduarda
authors.initials: E
authors.lastname: Pereira
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000187:drug effects* / Q000276:immunology; D001822:Body Burden; D002452:Cell Count; D006434:Hemocytes / Q000187:drug effects / Q000378:metabolism; D007108:Immune Tolerance; D007166:Immunosuppressive Agents / Q000378:metabolism / Q000633:toxicity*; D015227:Lipid Peroxidation / Q000187:drug effects; D008628:Mercury / Q000378:metabolism / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D007166:Immunosuppressive Agents; D014874:Water Pollutants, Chemical; D008628:Mercury