Diekman A B, Westbrook-Case V A, Naaby-Hansen S, Klotz K L, Flickinger C J, Herr J C
Center for Recombinant Gamete Contraceptive Vaccinogens, Department of Cell Biology, University of Virginia, Charlottesville 22908, USA.
Biol Reprod. 1997 Nov;57(5):1136-44. doi: 10.1095/biolreprod57.5.1136.
The anti-sperm monoclonal antibody (mAb) S19 was previously demonstrated to agglutinate human spermatozoa, inhibit sperm penetration of cervical mucus, and inhibit sperm-zona pellucida binding. These results implicated the cognate S19 antigen, designated sperm agglutination antigen-1 (SAGA-1), in gamete interactions and identified SAGA-1 as an attractive candidate for immunocontraceptive development. In the present study, evaluation of sperm agglutination with video microscopy showed that the S19 mAb rapidly and completely agglutinated human spermatozoa in a "tangled" pattern of agglutination. One- and two-dimensional immunoblot analyses identified SAGA-1 as a highly acidic, polymorphic sperm protein with an apparent molecular mass of 15-25 kDa and an isoelectric point of 2.5-3.0. Periodate treatment abolished this immunoreactivity, demonstrating that the S19 mAb reacted with a carbohydrate epitope and indicating that SAGA-1 is a glycoprotein. Absence of S19 immunoreactivity in postvasectomy seminal fluid implicated the testis, epididymis, and/or proximal vas deferens in the expression of SAGA-1. In solubility and phase partitioning assays, SAGA-1 was extracted from spermatozoa in Triton X-114 and exhibited the hydrophobic characteristics of integral and glycosylphosphatidyl inositol-anchored membrane proteins. These results identify SAGA-1 as a hydrophobic, highly acidic sperm glycoprotein that is localized on the entire sperm surface and has potential significance as a target for antibodies that inhibit sperm function and gamete interactions.
抗精子单克隆抗体（mAb）S19先前已被证明可凝集人类精子，抑制精子穿透宫颈黏液，并抑制精子与透明带的结合。这些结果表明同源的S19抗原，即精子凝集抗原-1（SAGA-1），参与配子相互作用，并将SAGA-1确定为免疫避孕开发的一个有吸引力的候选物。在本研究中，通过视频显微镜对精子凝集进行评估，结果显示S19单克隆抗体以“缠结”的凝集模式迅速且完全地凝集人类精子。一维和二维免疫印迹分析确定SAGA-1是一种高度酸性的多态性精子蛋白，表观分子量为15-25 kDa，等电点为2.5-3.0。过碘酸盐处理消除了这种免疫反应性，表明S19单克隆抗体与碳水化合物表位反应，这表明SAGA-1是一种糖蛋白。输精管切除术后精液中缺乏S19免疫反应性，这表明睾丸、附睾和/或输精管近端参与了SAGA-1的表达。在溶解度和相分配分析中，SAGA-1在Triton X-114中从精子中提取出来，并表现出整合膜蛋白和糖基磷脂酰肌醇锚定膜蛋白的疏水特性。这些结果确定SAGA-1是一种疏水、高度酸性的精子糖蛋白，它定位于整个精子表面，作为抑制精子功能和配子相互作用的抗体的靶点具有潜在意义。
