T-cell Responses in Oiled Guillemots and Swans in a Rehabilitation Setting

Gera M Troisi

doi:10.1007/s00244-013-9885-5

Abstract

Aquatic birds are commonly affected by oil spills. Despite rehabilitation efforts, the majority of rehabilitated common guillemots (Uria aalge) do not survive, whereas mute swans (Cygnus olor) tend to have higher postrelease survival. Polyaromatic hydrocarbons (PAHs) present in crude oil and diesel are immunotoxic in birds affecting cell-mediated responses to immunogens. Because it is a target of PAH toxicity, T-lymphocyte response to controlled mitogen administration (phytohemagglutinnin test) was investigated in a scoping study as a potentially useful minimally invasive in vivo test of cell-mediated immunity. The test was performed on 69 mute swans and 31 common guillemots stranded on the Norfolk and Lincolnshire coastline and inland waterways in England (UK) either due to injury or to contamination with crude or diesel oil. T-lymphocyte response was significantly decreased in swans with greater oil scores. T-lymphocyte responses were also decreased in guillemots, but this finding was not statistically significant.

Highlights

Aquatic birds are commonly affected by oil spills
Tests evaluating changes in immune tissue/organ histopathology, plasma thyroid hormone, retinol, cell-mediated (T-cell response, differential leucocyte counts), and humoral responses provide information on how contaminants interfere with immune function, and they have been used in avian biomonitoring studies (Peakall et al 1981; Grasman et al 1996; Newman et al 2000; Smits et al 2002; Troisi et al submitted)
Polyaromatic hydrocarbons (PAHs) affect cell-mediated immunity to a greater degree than humoral immunity (Rocke et al 1984), and the PHA test has been successfully used to assess the immunotoxicity of pollutants on T-lymphocyte responses in various bird species (Grasman 2002)

Summary

Introduction

Aquatic birds are commonly affected by oil spills. Despite rehabilitation efforts, the majority of rehabilitated common guillemots (Uria aalge) do not survive, whereas mute swans (Cygnus olor) tend to have higher postrelease survival. Because it is a target of PAH toxicity, T-lymphocyte response to controlled mitogen administration (phytohemagglutinnin test) was investigated in a scoping study as a potentially useful minimally invasive in vivo test of cell-mediated immunity. The phytohemagglutinin (PHA) skin test is a simple nondestructive in vivo method to study how T-lymphocyte response to mitogenic challenge may be altered due to contaminant exposure (Grasman 2002). This test has been validated by controlled dosing studies with polychlorinated biphenyls (PCBs) in birds and has been successfully applied in biomonitoring studies of organochlorine exposure in wild bird populations (Grasman et al 1996; Smits et al 2002; Sagerup et al 2009)

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Conclusion