SGER: Testing the Effects of Steroid Hormones on the Immune System

[705807] Sherman据推测，男性类固醇激素，特别是睾酮(T)，可抑制免疫系统功能。据说，与T水平较低的男性相比，T水平较高的男性产生免疫反应的能力较弱。如果是这样，睾酮水平高的男性应该更容易受到感染和寄生虫感染。为了调查这一假设，PI将使用红翼黑鸟作为脊椎动物模型。鸟类（24只）将在当地捕获并圈养10个月。每只猪将在(1)秋季（自然T水平低）、(2)早春（T水平上升）、(3)春季中期（育种期间T水平达到峰值）和(4)晚春（通过植入T水平提高）注射一种非致病性抗原（KLH）。在每个采样周期，免疫能力将用ELISA（酶联免疫吸附试验）来测量，ELISA是为量化该物种的肱骨免疫反应（抗体产生）而开发的；T水平将用放射免疫法定量测定。这项研究将提供关于自然产生和增强水平的类固醇激素如何影响野生脊椎动物免疫功能的精确信息。这也将帮助我们理解为什么只有一些雄性表现出夸张的依赖于t的第二性征（如羽毛、羽冠）。也许只有极其优质的雄性才能产生这样的性状，并保持生存所必需的免疫能力水平。选择这些雄性作为配偶的雌性在基因上有利于它们的儿子和女儿。因此，这个探索性项目融合了三个研究领域（免疫学、内分泌学和行为生态学），并有望开辟一个新的研究领域，研究激素和免疫系统之间的相互作用如何影响性选择。

9705807 Sherman It has been hypothesized that male steroid hormones, particularly testosterone (T), suppress immune system functions. Males with high T levels are said to be less capable of mounting an immune response that males with lower T levels. If so, males with high T levels should be more susceptible to infections and parasitic infestations. To investigate this hypothesis, the PI will use as a vertebrate model, the red-winged blackbird. Birds (24) will be captured locally and maintained in captivity for 10 months. Each will be injected with a non-pathogenic antigen (KLH) in the (I) autumn (natural T levels low), (ii) early spring (rising T levels), (III) mid-spring (peak T levels, during breeding), and (iv) late-spring (T levels boosted higher with an implant). At each sampling period, immunocompetence will be measured with an ELISA (enzyme linked immunosorbent assay) that was developed for quantifying humeral immune responses (antibody production) in this species; T levels will be quantified with a radioimmunoassay. This research will yield precise information on how naturally-produced and enchanced levels of steroid hormones affect immune functions in a wild vertebrate. It will also help us to understand why only some males express exaggerated T-dependent secondary sexual characters (e.g., plumes, crests). Perhaps only extremely high-quality males can produce such characters and also maintain levels of immunocompetence necessary for survival. Females that choose these males as mates benefit their sons and daughters genetically. This exploratory project thus merges three fields of research (immunology, endocrinology, and behavioral ecology) and promises to open up a new area of investigation into how interactions between the hormone and immune systems affect sexual selection.