title: Short-term exposure of Chinook salmon (Oncoryhnchus tshawytscha) to o,p-DDE or DMSO during early life-history stages causes long-term humoral immunosuppression.
abstract: We evaluated the effect of short-term exposures to a xenobiotic chemical during early life-history stages on the long-term immune competence of chinook salmon (Oncoryhnchus tshawytscha). Immersion of chinook salmon eggs in a nominal concentration of o,p-dichlorodiphenyldichloroethylene (o,p-DDE; 10 ppm) for 1 hr at fertilization followed by immersion in the same dose for 2 hr at hatch resulted in a significant reduction in the ability of splenic leukocytes from fish 1 year after treatment to undergo blastogenesis upon in vitro stimulation with lipopolysaccharide. We also observed that the vehicle, dimethyl sulfoxide (DMSO), caused a significant reduction in the ability of the splenic leukocytes to express surface immunoglobin M (SIgM) at this time. The concentration of o,p-DDE in a pooled sample of whole fry from this treatment was 0.53 microg/g lipid 1 month after first feeding but was undetectable in all other treatments. Mortality rate, time to hatch, fish length, and weight were unaffected by treatment with o,p-DDE. Similarly, sex ratios, gonadal development, and concentrations of plasma estradiol and 11-ketotestosterone were not affected by the treatment. In addition, we found no evidence that plasma lysozyme concentrations or the mitogenic responses of splenic leukocytes to concanavalin A or polyinosinic-polycytidylic acid were influenced by the treatment. In this experiment, a brief period of exposure to o,p-DDE or DMSO during early development was able to induce long-term effects on humoral immune competence of chinook salmon. Such immunosuppression may increase susceptibility to disease, which may in turn be critical to regulating the population.
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 97331-3803, USA. milstonr@bcc.orst.edu
authors.forename: Ruth H
authors.initials: RH
authors.lastname: Milston
authors.forename: Martin S
authors.initials: MS
authors.lastname: Fitzpatrick
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Vella
authors.forename: Shaun
authors.initials: S
authors.lastname: Clements
authors.forename: Deke
authors.initials: D
authors.lastname: Gundersen
authors.forename: Grant
authors.initials: G
authors.lastname: Feist
authors.forename: Tawni L
authors.initials: TL
authors.lastname: Crippen
authors.forename: Joann
authors.initials: J
authors.lastname: Leong
authors.forename: Carl B
authors.initials: CB
authors.lastname: Schreck
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D004121:Dimethyl Sulfoxide / Q000633:toxicity*; D005260:Female; D006066:Gonads / Q000254:growth & development; D007108:Immune Tolerance / Q000187:drug effects; D007814:Larva / Q000254:growth & development / Q000276:immunology; D008297:Male; D008939:Mitotane / Q000031:analogs & derivatives* / Q000633:toxicity*; D012474:Salmon / Q000276:immunology*; D012744:Sex Ratio; D012997:Solvents / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D012997:Solvents; D014874:Water Pollutants, Chemical; D008939:Mitotane; C054919:2,2-(2-chlorophenyl-4'-chlorophenyl)-1,1-dichloroethene; D004121:Dimethyl Sulfoxide