The Toxic Effects of Multiple Persistent Organic Pollutant Exposures on the Post-Hatch Immunity Maturation of Glaucous Gulls

Abstract

This study tested whether the immune system of the glaucous gull (Larus hyperboreus) chicks became affected by existing environmental contaminants. An experimental group was given food that mimicked the natural contaminant mixture found in food from the North Atlantic marine environment, while the control group was given the equivalent of nearly clean food. All chicks were immunized with herpes virus (EHV), reovirus (REO), influenza virus (EIV), and tetanus toxoid (TET) in order to test their ability to respond to foreign specific antigens. At 8 wk, the experimental group had 3- to 13-fold higher concentrations of hexachlorobenzene (HCB), oxychlordane, p,p′-DDE, and total polychlorinated biphenyls (ΣPCB) than did the control. The experimental group produced significantly lower antibody titer against EIV and had lower concentrations of immunoglobulin-G (IgG) and -M (IgM) in blood. Hematocrit percent and leukocyte numbers did not differ between the two groups. The ability of lymphocytes to proliferate in vitro was tested with three mitogens, phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM), and three antigens, keyhole limpet hemocyanin (KLH), TET, and Mycobacterium avium subsp. paratuberculosis tuberculin purified protein derivative (PPD). The experimental group had a significantly higher peripheral blood lymphocyte response to PHA and to spleen lymphocytes in vitro stimulated with Con A and PCB congeners 99 or 153, while the Con A, PWM, KLH, TET, PPD, and Con A plus PCB-156 or -126 showed nonsignificant differences between groups. Data indicate that the combined effect of multiple persistent organic pollution exposures occurring naturally in the Arctic negatively affect the immune system of the glaucous gull chick.

Acknowledgements

We thank Grete Berntsen, Chris Bingham, Tine Borgen, Vegard Bunes, Heather Coleman, Signe Haugen, Åse Krøkkje, Anuschka Polder, Tor Gunnar Solvang, and Ole Gunnar Støen for technical assistance during the experiment and with the analyses. We also thank Rob Barrett and four anonymous reviewers for comments that greatly improved the article. The Transport and Effect Program and the Norwegian Pollution Control Authority were the main financial contributors for the study. The Norwegian Polar Institute, the Norwegian School of Veterinary Science, the National Veterinary Institute, the Roald Amundsen Centre for Arctic Research, and the University of Tromsø have also supported the study.