Background Self-incompatibility, fusion/non-fusion reactions, and contact reactions (CRs) have all been identified as allorecognition phenomena in ascidians. CR is a reaction characteristic of the hemocytes of Halocynthia roretzi, whereby they release phenol oxidase (PO) upon contact with non-self hemocytes. Thus, these cells may represent a primitive form of the vertebrate immune system. In the present study, we focused on the CR of H. roretzi hemocytes and sought to identify self-marker proteins that distinguish between self and non-self cells. Results We initially generated a CR-inducing monoclonal antibody against the complete hemocyte membrane-protein complement (mAb11B16B10). This antibody was identified based on the differential induction of PO activity in individual organisms. The level of PO activity induced by this antibody in individual ascidians was consistent with the observed CR-induced PO activity. mAb11B16B10 recognized a series of 12 spots corresponding to a 100-kDa protein, with differing isoelectric points (pIs). A comparison of the 2D electrophoresis gels of samples from CR-reactive/non-reactive individuals revealed that some spots in this series in hemocytes were common to the CR-non-inducible individuals, but not to CR-inducible individuals. We cloned the corresponding gene and named it Halocynthia roretzi self-marker-like protein-1 (HrSMLP1). This gene is similar to the glycoprotein DD3-3 found in Dictyostelium, and is conserved in invertebrates. Conclusion We generated a CR-inducing monoclonal antibody (mAb11B16B10) that recognized a series of novel membrane proteins (HrSMLP1) in the hemocytes of H. roretzi. The combination of expressed spots of HrSMLP1 distinguishes non-self cells from self cells with respect to CR inducibility. Given that the HrSMLP1 gene is a single gene, it may represent a novel type of self-marker protein with a role in CR.

中文翻译：

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类似自我标记的蛋白质控制 Halocynthia roretzi 的血细胞同种异体识别。


背景 自交不亲和性、融合/非融合反应和接触反应（CR）均已被确定为海鞘的同种异体识别现象。 CR是Halocynthia roretzi血细胞的一种反应特征，它们在与非自身血细胞接触时释放酚氧化酶(PO)。因此，这些细胞可能代表脊椎动物免疫系统的原始形式。在本研究中，我们关注 H.roretzi 血细胞的 CR，并试图鉴定区分自身细胞和非自身细胞的自我标记蛋白。结果我们最初生成了针对完整血细胞膜蛋白补体 (mAb11B16B10) 的 CR 诱导单克隆抗体。该抗体是根据个体生物体中 PO 活性的差异诱导而鉴定的。该抗体在海鞘个体中诱导的 PO 活性水平与观察到的 CR 诱导的 PO 活性一致。 mAb11B16B10 识别一系列 12 个点，对应于 100 kDa 的蛋白质，具有不同的等电点 (pIs)。对来自 CR 反应性/非反应性个体的样品的 2D 电泳凝胶的比较表明，血细胞中该系列中的一些斑点对于 CR 非诱导型个体是常见的，但对于 CR 诱导型个体则不然。我们克隆了相应的基因，并将其命名为Halocynthia roretzi自我标记样蛋白1（HrSMLP1）。该基因与盘基网柄菌中发现的糖蛋白 DD3-3 相似，在无脊椎动物中是保守的。结论 我们生成了一种 CR 诱导单克隆抗体 (mAb11B16B10)，该抗体可识别 H. roretzi 血细胞中的一系列新型膜蛋白 (HrSMLP1)。 HrSMLP1 表达点的组合可在 CR 诱导能力方面区分非自体细胞和自体细胞。 鉴于 HrSMLP1 基因是单个基因，它可能代表一种在 CR 中发挥作用的新型自我标记蛋白。