RUI: Fate of Xenografts in Biomphalaria glabrata (Mollusca: Pulmonata)

当组织移植物从一种软体动物移植到另一种软体动物(异种移植物)时，据报道移植物失败，即死亡。这项研究的目的是了解软体动物异种移植失败的机制。具体地说，这项研究将评估(1)供体和受者之间的生理不相容和(2)受者免疫排斥的相对作用。方法将包括将来自系统发育接近和系统发育遥远物种的心脏移植到单一受体蜗牛物种中。移植的命运将被组织学和组织化学跟踪，并将与体外维持的心脏的命运进行比较，并与来自同一物种捐赠者的植入的命运进行比较。此外，免疫系统的作用将通过对免疫抑制的接受者进行植入来确定，即感染了幼虫吸虫的蜗牛。最后，通过在植入前对移植物进行化学修饰，如神经氨酸酶消化和凝集素结合，可以获得关于异种移植物上被识别为非自我的决定因素类型的初步信息。这个项目的潜在意义在于，它可能有助于阐明软体动物中免疫样自我识别的机制，为研究脊椎动物中也存在的原始自我识别形式提供一个模型，并为重要软体动物群体的系统发育关系提供信息。

When tissue gafts are transplanted from one species of mollusc to another (xenografts), the grafts reportedly fail, i.e., die. The goal of the proposed research is to understand the mechanisms of xenograft failure in molluscs. Specifically, the study will assess the relative roles of (1) physiological incompatibility between donor and recipient and (2) immunological rejection by the recipient. Methods will include implantation of hearts from phylogenetically close and phylogenetically distant species into a single recipient snail species. Fates of the implants will be followed histologically and histochemically, and will be compared to fates of hearts maintained in vitro, and to fates of implants from donors of the same species. In addition, the role of the immune system will be ascertained by conducting implants in immunosuppressed recipients, i.e., snails infected with larval trematodes. Finally, initial information on the types of determinants on the xenograft recognized as non-self will be gained by subjecting grafts to chemical modification such as neuraminidase digestion and lectin binding prior to implantation. The potential significance of this project is that it may help to elucidate the mechanisms of immune-like self recognition in molluscs, serve as a model for studying primitive forms of self recognition that also occur in vertebrates, and provide information on phylogenetic relationships within an important group of molluscs.