Antigen changes of monoclonal antibody MSH27 in process of post-testicular maturation (in mice)

An anti-mouse spermatozoon monoclonal antibody, MSH27, as well as its purified antigen, can block sperm-egg membrane fusion. As a candidate protein for sperm-egg membrane fusion, the sperm antigen was investigated in the process of post-testicular maturation (PTM). The molecule was produced in testes and located on the plasma membrane of the postacrosomal area of the spermatozoon. However, the epitope recognized by the MSH27 (MSH27Ep) was not exposed until the occurrence of the acrosome reaction. In the process of fertilization, spermatozoa must complete the acrosome reaction before penetrating across the zona pellucidas (ZPs) to approach the plasma membrane of eggs. The effects of the acrosome reaction and penetration of the ZP on the exposure of the MSH27Ep were also studied. It was shown that the percentage of the spermatozoa with the MSH27Ep exposed increased followed with their mature status in PTM. In fact, it bad a linear correlativity with the rate of the acrosome reaction. After spermatozoa had     

小鼠精子睾丸后成熟过程中单克隆抗体MSH27抗原表位的显露

MSH2 7是一株抗小鼠精子的单克隆抗体 ,此抗体及其纯化的抗原分子在体外受精实验中均可以阻止精卵膜融合 ,因而推测其抗原在精卵膜融合过程中具有重要的作用 .这里探讨了抗原分子在精子睾丸后成熟过程中MSH2 7识别表位的显露条件 .MSH2 7抗原分子在睾丸中产生 ,定位于精子顶体后区的质膜上 ;但MSH2 7所识别的抗原表位只在顶体反应后的精子上表露 .在受精过程中 ,精子必须完成顶体反应并穿过卵子的透明带才能接近卵子质膜并与之融合 .同时还研究了顶体反应和穿透明带作用对MSH2 7表位显露的影响 .在附睾成熟过程中 ,随着精子在附睾中的转运 ,它们发生顶体反应的能力不断增加 ;精子抗原表位的显露呈现顶体反应依赖性 ,且两者呈现线性回归关系 .钙离子载体A2 3 187诱发顶体反应后 ,MSH2 7染色阳性的精子远远少于顶体反应的精子 ;但穿过透明带后绝大多数精子 ( 98% )呈现MSH2 7染色阳性 .总之 ,在睾丸后成熟 (附睾成熟、获能、顶体反应 )和精子穿透明带的过程中 ,对整个精子群体来讲 ,单抗MSH2 7所识别的抗原表位的显露和精子最终获得穿入卵子质膜的能力是同步发生的 .     

中红侧沟茧蜂雌蜂输卵管萼中病毒样纤丝的特征和功能

中红侧沟茧蜂Microplitis mediator雌蜂输卵管萼中有一种病毒样纤丝（virus-like filaments, VLFs）。在蜂卵从卵巢管通过输卵管萼产出的过程中,VLF包裹在蜂卵的表面,随蜂卵进入寄主体内。透射电镜显示,VLF中心是电子致密物质,外有单层膜包被,直径约35 nm。负染技术表明,VLF是具有左螺旋结构的纤丝,负染时的直径约25 nm。不含VLF的蜂卵进入3龄初寄主后,全部被寄主血细胞包囊;含有VLF的蜂卵进入同样的寄主后,88.2%受到保护。VLF对蜂卵的保护作用在不同发育期的寄主中不同,在3龄初的粘虫体内,平均有64.7%的初产卵不被包囊,而在4龄初的粘虫体内,只有9.5%的初产卵受到保护。这一结果说明,VLF只能为蜂卵提供部分的保护作用,需配合其它寄生蜂因子（萼液、蜂毒等）共同作用于寄主的免疫系统。