PARENT SESSION
PS10 - Immunotoxicity
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P118) Immunotoxicity of in ovo exposure to PCB 126 in juvenile chickens.
Croisant, Emma*,1, Grasman, Keith1, Bowerman, William2, 1 Wright State University, Dayton, OH, USA2 Clemson University, Pendleton, SC, USA
ABSTRACT- Fish-eating birds of the Great Lakes, including bald eagles (Haliaeetus leucocephalus), are exposed to organochlorine contaminants that have been associated with immunosuppression in several wild species. The immunotoxicity of PCBs is well studied in rodents but is less understood in avian species. We tested the hypothesis that developmental exposure to PCB 126 causes suppressed immune function in juvenile chickens post-hatch. Previous studies by the authors showed suppression of humoral immune function after an in ovo exposure to 0.25 ng/g PCB 126. This study expanded the dose range used previously and was designed to lead to the development of health effects biomarkers to be used in bald eagle biomonitoring. Fertilized, leghorn chicken eggs were unexposed or injected with 0, 0.100, 0.175, 0.250 or 0.325 ng/g of PCB 126 in sunflower oil into the air cell. In addition to immune function, mortality, deformities, growth and endocrine function were assessed and results are reported elsewhere. The phytohemagglutinin (PHA) skin test, immune organ mass and cellularity and antibody response to sheep red blood cells (SRBC) were used to analyze T-cell mediated immunity, immune organ atrophy and humoral immune function respectively. There was an insignificant declining trend in PHA skin test response at 11 days post-hatch (p=0.14). At day 14, thymus and bursal index showed significantly declining trends with dose (p<0.005). At day 28, anti-SRBC titer was decreased in all PCB exposed birds up to 50% (p=0.1). Immunosuppression was most often noted at the 0.25 and 0.325 ng/g doses. Results were comparable to previous studies of the same design and provided evidence for immunotoxicity of PCB 126 after an in ovo exposure with no post-hatch exposure.
Key words: immunotoxicology, PCB 126, chicken, egg injection