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

9705807谢尔曼据推测，雄性类固醇激素，特别是睾酮（T），抑制免疫系统功能。 据说，T水平高的男性比T水平低的男性更不容易产生免疫反应。 如果是这样的话，T水平高的男性应该更容易受到感染和寄生虫感染。 为了研究这一假设，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。 每一只都将在以下时间注射非致病性抗原（KLH）：（I）秋季（天然T水平低），（ii）早春（T水平上升），（III）仲春（繁殖期间T水平达到峰值）和（iv）晚春（植入物使T水平升高）。 在每个采样期，将使用ELISA（酶联免疫吸附试验）测量免疫活性，该试验用于定量该种属的肱骨免疫应答（抗体产生）;将使用放射免疫测定法定量T水平。 这项研究将产生关于天然产生和增强的类固醇激素水平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男性表达夸张的T依赖性第二性征（例如，羽状物、冠状物）。 也许只有极高质量的雄性才能产生这样的特征，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从遗传上有利于她们的儿子和女儿。 因此，这个探索性的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.