Department of Biology, The College of William and Mary, Institute for Integrative Bird Behavior Studies, Williamsburg, VA 23187, USA.
Arch Environ Contam Toxicol. 2013 Feb;64(2):327-36. doi: 10.1007/s00244-012-9830-z. Epub 2012 Nov 15.
Mercury (Hg) is a ubiquitous contaminant with deleterious effects on many wildlife species. Most studies to date have focused on fish-eating birds and mammals because much historical Hg pollution is aquatic. Recently, however, comparable blood-Hg levels have been found in terrestrial insectivorous songbirds. As a result, research is needed to clarify the effects of Hg exposure on songbirds. One fundamental end point that is still poorly understood is the effect of Hg on the songbird immune system. If Hg affects the functioning of the immune system, exposed songbirds may be less able to mount an appropriate immune response against invading pathogens. To gain insight into how Hg affects songbird immune function on a cellular level, a flow cytometric assay was developed to measure lipopolysaccharide-induced B-lymphocyte proliferation in zebra finches (Taeniopygia guttata). This is the first experimental (dosing) study of the potential effect of Hg on songbird immune system functioning. Decreased B cell proliferation was observed after lipopolysaccharide exposure in individuals with greater concentrations of Hg in their blood and tissues. In addition, these individuals had decreased ratios of proliferating-to-resting B cells. This decrease in lymphocyte proliferation in response to an effective mitogen suggests that environmental exposure to sublethal levels of Hg may inhibit or delay B cell proliferation in songbirds, potentially increasing susceptibility to disease and decreasing survivorship.
汞（Hg）是一种普遍存在的污染物，对许多野生动物物种都有有害影响。迄今为止，大多数研究都集中在食鱼的鸟类和哺乳动物上，因为历史上很多汞污染都来自于水体。然而，最近在以昆虫为食的陆生鸣禽中也发现了类似的血液汞水平。因此，需要研究来阐明汞暴露对鸣禽的影响。一个仍未被充分理解的基本终点是汞对鸣禽免疫系统的影响。如果汞影响免疫系统的功能，那么暴露的鸣禽可能就无法对入侵病原体产生适当的免疫反应。为了深入了解汞如何在细胞水平上影响鸣禽的免疫功能，开发了一种流式细胞术测定法来测量斑胸草雀（Taeniopygia guttata）中脂多糖诱导的 B 淋巴细胞增殖。这是第一个关于汞对鸣禽免疫系统功能潜在影响的实验（给药）研究。在血液和组织中汞浓度较高的个体中，在脂多糖暴露后观察到 B 细胞增殖减少。此外，这些个体的增殖 B 细胞与静息 B 细胞的比例降低。淋巴细胞对有效有丝分裂原的增殖减少表明，环境暴露于亚致死水平的汞可能会抑制或延迟鸣禽 B 细胞的增殖，从而增加患病的易感性并降低存活率。
