De Tomaso Anthony W, Nyholm Spencer V, Palmeri Karla J, Ishizuka Katherine J, Ludington William B, Mitchel Katrina, Weissman Irving L
Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, USA.
Nature. 2005 Nov 24;438(7067):454-9. doi: 10.1038/nature04150.
Histocompatibility--the ability of an organism to distinguish its own cells and tissue from those of another--is a universal phenomenon in the Metazoa. In vertebrates, histocompatibility is a function of the immune system controlled by a highly polymorphic major histocompatibility complex (MHC), which encodes proteins that target foreign molecules for immune cell recognition. The association of the MHC and immune function suggests an evolutionary relationship between metazoan histocompatibility and the origins of vertebrate immunity. However, the MHC of vertebrates is the only functionally characterized histocompatibility system; the mechanisms underlying this process in non-vertebrates are unknown. A primitive chordate, the ascidian Botryllus schlosseri, also undergoes a histocompatibility reaction controlled by a highly polymorphic locus. Here we describe the isolation of a candidate gene encoding an immunoglobulin superfamily member that, by itself, predicts the outcome of histocompatibility reactions. This is the first non-vertebrate histocompatibility gene described, and may provide insights into the evolution of vertebrate adaptive immunity.
组织相容性——生物体区分自身细胞和组织与其他细胞和组织的能力——是后生动物中的一种普遍现象。在脊椎动物中，组织相容性是由高度多态性的主要组织相容性复合体（MHC）控制的免疫系统的一种功能，该复合体编码针对外来分子以供免疫细胞识别的蛋白质。MHC与免疫功能的关联表明后生动物组织相容性与脊椎动物免疫起源之间存在进化关系。然而，脊椎动物的MHC是唯一具有功能特征的组织相容性系统；非脊椎动物中这一过程的潜在机制尚不清楚。一种原始脊索动物，即海鞘Botryllus schlosseri，也会经历由一个高度多态性位点控制的组织相容性反应。在这里，我们描述了一个编码免疫球蛋白超家族成员的候选基因的分离，该基因本身就能预测组织相容性反应的结果。这是所描述的第一个非脊椎动物组织相容性基因，可能为脊椎动物适应性免疫的进化提供见解。
