RESEARCH FOR MCP IN SEMEN AND SPERM-EGG INTERACTION

1.膜辅因子蛋白（MCP），CD 46，其主要功能是保护宿主细胞免受同源补体的侵害，被认为是精子与卵母细胞的粘附分子。本研究的目的是阐明附睾精子表达MCP的特性与其在最近开发的辅助生殖策略中的可重复性之间的关系。我们收集了正常受试者的射出精子和输精管切除术受试者和先天性输精管缺失患者的附睾精子。免疫印迹法和辅因子活性测定法研究了MCP的结构和功能特性，结果表明，与射出精子相比，附睾精子的补体调节活性较弱，且精子的可复性性降低，与MCP抗体的反应也较差。MCP在正常发育的男性附睾中的精子中充分表达，但在先天性或获得性输精管阻塞的男性附睾精子中表达减少。2. 3例符合常规精液分析正常或低于正常标准的不育受试者，通过使用一组单克隆抗体的SDS-PAGE/免疫印迹分析显示精子CD 46（补体膜辅因子蛋白）异常。据报道，精子CD 46亚型与精卵相互作用有关。这3例患者的淋巴细胞和粒细胞表达正常的CD 46亚型。因此，这些蛋白质中的精子特异性异常与男性不育症相似，提示了一种新的不育症类型，可能是由于与精子-卵子相互作用相关的分子的畸变。

1.Membrane cofactor protein (MCP), CD46, whose primary function is to protect host cells from homologous complement, has been presumed to serve as a sperm adhesion molecule for oocytes. The purpose of this study was to clarify the relationship between the properties of MCP expressed on epididymal sperm and their fertilizing ability in a recently developed strategy for assisted reproduction. We collected ejaculated sperm from normal subjects and epididvmal sperm from vasectomized subjects and patients with congenital absence of the vas deferens. Westent blotting and cofactor activity assay were performed to investigated the structural and functional properties of MCP.Epididymal spermatozoa which showed a reduced fertilizing ability tended to react poorly with antibodies against MCP and also showed low cofactor activity, indicating weak complement regulatory activity compared to that of ejaculated spermatozoa. MCP is sufficiently expressed in ejaculated sperm in men with a normally developed epididymis but is diminished in epididymal sperm from men with congenital or acquired obstruction of the vas deferens.2.Three infertile subjects fulfillling normal or subnormal criteria on routine semen analysis showed abnormal sperm CD46 (membrane cofactor protein of complement) by SDS-PAGE/immunoblotting analysis using a panel of monoclonal antibodies. The sperm CD46 isoform has been reported to be associated with sperm-egg interaction. These 3 patients expressed normal CD46 isoforms on their lymphocytes and granulocytes. Thus, sperm-specific abnormalities in these proteins parallels male infertility, suggesting a new category of infertility, probably due to aberrations in the molecules related to sperm-egg interaction.