Saino N, Canova L, Fasola M, Martinelli R
Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy e-mail:
Dipartimento di Biologia Animale, Università degli Studi di Pavia, Piazza Botta 9, 27100 Pavia, Italy, , , , , , IT.
Oecologia. 2000 Aug;124(3):358-366. doi: 10.1007/s004420000395.
Density dependence is a common feature in the dynamics of animal populations. Availability of food resources critical to immunity is likely to be one of the mechanisms mediating the effect of population density on individual fitness. The ability to mount an immune response to an antigen is also affected by levels of immunosuppressive hormones associated with reproduction or mediating the response to ecological and social stress. We assessed variation in condition and intensity of humoral immune response to a T-cell-dependent antigen in bank voles (Clethrionomys glareolus) by experimentally altering population density before immunisation. Consistent with our prediction, males had lower humoral immunocompetence in the breeding than in the non-breeding season. Contrary to our expectation, males did not show enhanced immunocompetence and females showed depressed humoral immune response under experimentally lowered population density. Variation of immune response in relation to population density depended on sex, with females but not males showing lower immune response under experimentally reduced density. We conclude that humoral immunity of bank voles was affected by reproduction and social environment rather than by population density.
密度依赖性是动物种群动态中的一个常见特征。对免疫至关重要的食物资源的可获得性可能是介导种群密度对个体适应性影响的机制之一。对抗抗原的免疫反应能力也受到与繁殖相关或介导对生态和社会压力反应的免疫抑制激素水平的影响。我们通过在免疫前实验性地改变种群密度，评估了田鼠（黄毛鼠）对T细胞依赖性抗原的体液免疫反应的状态和强度的变化。与我们的预测一致，雄性在繁殖季节的体液免疫能力低于非繁殖季节。与我们的预期相反，在实验性降低的种群密度下，雄性没有表现出增强的免疫能力，而雌性则表现出体液免疫反应受到抑制。免疫反应相对于种群密度的变化取决于性别，在实验性降低的密度下，雌性而非雄性表现出较低的免疫反应。我们得出结论，田鼠的体液免疫受到繁殖和社会环境的影响，而不是种群密度的影响。
