Phylogenetic aspects of the cyclostomes with special attention to the primitive complement sysytem.

盲鳗是现存最原始的脊椎动物，它的免疫系统主要是先天性的。为了了解先天免疫系统的进化，我们从盲鳗血清中分离出补体C3。在这项研究中，我们试图通过RT-PCR进行鉴定的盲鳗C3转化酶使用变性引物设计的基础上保守的氨基酸之间的几种丝氨酸蛋白酶的延伸。使用克隆的RT-PCR产物之一作为探针分析从八目鳗肝cDNA文库分离的全长cDNA克隆，表明该cDNA编码八目鳗甘露糖结合凝集素相关丝氨酸蛋白酶（WASP）1。这一证据有力地表明盲鳗至少通过由凝集素途径组成的补体系统来防御病原体

Hagfish is the most, primitive extant vertebrate and thought to defend itself against pathogens only by innate immune system. With a view to understanding the evolution of the innate immune system, we have isolated complement C3 from the serum of hagfish. In this study, our attempt to identify a hagfish C3 convertase was carried out by RT-PCR using degenerative primers designed on the basis of the conserved amino acid stretches among the several kinds of serine proteases. Analyses of a full-length cDNA clone isolated from a hagfish liver cDNA library using one of the cloned RT-PCR products as a probe indicated that this cDNA encoded hagfish mannose-binding lectin-associated serine protease WASP)1. This evidence strongly suggests that the hagfish defends itself against pathogens at least by the complement system composed of lectin pathway