Studies on the mechanism of allorecognition in botryllid ascidians

1.在几种海鞘中，不同种海鞘的识别方式略有不同。这种异源识别方式的多样性是由参与异源排斥反应的血细胞类型的差异、同种血细胞功能的差异以及异源识别位点在殖民地中的分布所引起的。2.通过对一种复合海鞘和几种葡萄状海鞘的同种异体排斥反应的比较研究，明确了桑椹胚细胞主要参与的同种异体排斥反应是葡萄状海鞘的mpst原始反应。此外，从rDNA分析中得到的葡萄孢的同源性与从异源识别方式的多样性推测的结果基本一致.本实验研究了同种异体排斥反应时血细胞中特异性或特异性增加的mRNA，共获得23条cDNA。其中6个与哺乳动物免疫相关基因相似。其中3个与哺乳动物MHCIII连锁的热休克蛋白70（HSP 70）高度相似。其中两个与B.schlosseri已知的蛋白相同，分别为HSP 70.1和HSP 70.2，而最后一个是一个新的热休克蛋白，其基因长度约为3kb。该基因全长900个碱基，与哺乳动物MHCIII连锁的HSP 70基因序列有77%的同源性。该蛋白的氨基酸序列与哺乳动物MHCIII连锁的HSP 70的氨基酸序列也显示出高度的相似性（83%）。目前，我们正在研究该蛋白在同种异体排斥反应中的作用以及在排斥反应中在殖民地中的分布。

1. Among several species of botryllid ascidians, the manners of allorecognition of those species are slightly different from each other. This variety of the allorecognition manners is caused by the difference of blood cell types participating in allorejection, and the difference of function in the same type blood cells, as well as allorecognition sites distributed in the colony. 2.From the comparative study of allorejection reaction among a compound styelid ascidian and some botryllid ascidians, it was cleared that the allorejection in which morula cells mainly participate is the mpst primitive reaction in botryllids. Furthermore, the phylogeny of botryllids obtained from rDNA analysis is almost the same as that speculated from the variety of allorecognition manners.3. The specific or specifically increasing mRNAs in the blood cells at the allorejection reaction were investigated, and 23 cDNA were gained from this experiment. Six of them were similar to the genes related with immunity of mammals. Furthermore, three of them showed high similarity to the heat shock protein 70 (HSP 70) linked with MHCIII of mammals. Two of these three were the same as the already known proteins in B.schlosseri, HSP 70.1 and HSP 70.2, respectively, but the last one was a new heat shock protein of which gene is about 3 kb in length. The sequence of 900 bases of this gene has been cleared, and that sequence shows 77%similarity to that of HSP 70 linked with MHCIII of mammals. The amino acid sequence of this protein also shows high similarity (83 %) to that of HSP 70 linked with MHCIII of mammals. Now, we are investigating on the role of this protein in the allorejection and distribution in the colony during allorejection.