Ka. Grasman et al., ORGANOCHLORINE-ASSOCIATED IMMUNOSUPPRESSION IN PREFLEDGLING CASPIAN TERNS AND HERRING-GULLS FROM THE GREAT-LAKES - AN ECOEPIDEMIOLOGICAL STUDY, Environmental health perspectives, 104, 1996, pp. 829-842
The objectives of this study were to determine whether contaminant-ass
ociated immunosuppression occurs in prefledgling herring gulls and Cas
pian terns from the Great lakes and to evaluate immunological biomarke
rs for monitoring health effects in wild birds. During 1992 to 1994, i
mmunological responses and related variables were measured in prefledg
ling chicks at colonies distributed across a broad gradient of organoc
hlorine contamination (primarily polychlorinated biphenyls), which was
measured in eggs. The phytohemagglutinin skin test was used to assess
T-lymphocyte function. in both species, there was a strong exposure-r
esponse relationship between organochlorines and suppressed T-cell-med
iated immunity. Suppression was most severe (30-45%) in colonies in La
ke Ontario (1992) and Saginaw Bay (1992-1994) for both species and in
western Lake Erie (1992) for herring gulls. Both species exhibited bio
logically significant differences among sites in anti-sheep red blood
cells antibody titers, but consistent exposure-response relationships
with organochlorines were not observed. in Caspian terns and, to a les
ser degree, in herring gulls, there was an exposure-response relations
hip between organochlorines and reduced plasma retinol (vitamin A). In
1992, altered white blood cell numbers were associated with elevated
organochlorine concentrations in Caspian terns but not herring gulls.
The immunological and hematological biomarkers used in this study reve
aled contaminant-associated health effects in wild birds. An epidemiol
ogical analysis strongly supported the hypothesis that suppression of
T-cell-mediated immunity was associated with high perinatal exposure t
o persistent organochlorine contaminants.