Gaunt S J
J Embryol Exp Morphol. 1985 Aug;88:55-69.
By use of a monoclonal antibody, 2B5, in indirect immunofluorescence experiments, it was found that both fertilized and unfertilized mouse eggs obtained directly from the oviduct commenced expression of a cell surface antigen at about 5 h after ovulation. Surface labelling became intense by 16 h after ovulation and persisted over all blastomeres throughout preimplantation development. In contrast, embryos cultured in vitro did not appearance of 2B5 antigen until about 48 h after ovulation, at which time they were at the 2- to 4-cell stage. Antigen expression in vitro commonly began on a single blastomere and did not appear consistently over all blastomeres until the 8-cell stage (72 h after ovulation). Unfertilized eggs maintained for 72 h in culture did not acquire 2B5 antigen. It is postulated that the absence of 2B5 antigen on 1-cell eggs cultured in vitro may be due either to a failure of normal synthesis by eggs as a result of a deficiency in the culture medium, or alternatively, to absence of a soluble oviduct factor which carries the 2B5 antigen, and which normally becomes bound to the surface of eggs after ovulation. The second of these two possibilities was supported by egg transfer experiments which showed that unfertilized eggs within the oviduct became 2B5 antigen-positive even after their prior fixation in glutaraldehyde. By the 2- to 4-cell stage, however, embryos developed their own capacity for synthesis of 2B5 antigen-positive cell surface molecules. This synthesis was inhibited by tunicamycin, suggesting that the antigenic site involved the sugar component of glycoprotein. The range of tissues within the postimplantation embryo and adult reproductive tracts which labelled with 2B5 antibody was found to be very similar to that known for SSEA-1 monoclonal antibody (Solter & Knowles, 1978; Fox et al. 1981; Fox, Damjanov, Knowles & Solter, 1982), and as further evidence of a relationship between 2B5 and SSEA-1 antigens it was found that 125I SSEA-1 antibody could be blocked in its binding to teratocarcinoma cells by preincubation in 2B5 monoclonal antibody.
通过在间接免疫荧光实验中使用单克隆抗体2B5，发现直接从输卵管获得的受精和未受精小鼠卵在排卵后约5小时开始表达一种细胞表面抗原。排卵后16小时表面标记变得强烈，并在植入前发育过程中在所有卵裂球上持续存在。相比之下，体外培养的胚胎直到排卵后约48小时才出现2B5抗原，此时它们处于2至4细胞阶段。体外抗原表达通常在单个卵裂球上开始，直到8细胞阶段（排卵后72小时）才在所有卵裂球上一致出现。在培养中维持72小时的未受精卵没有获得2B5抗原。据推测，体外培养的1细胞卵上缺乏2B5抗原可能是由于培养基缺乏导致卵正常合成失败，或者是由于缺乏携带2B5抗原的可溶性输卵管因子，而该因子通常在排卵后与卵表面结合。这两种可能性中的第二种得到了卵转移实验的支持，该实验表明输卵管内的未受精卵即使在先前用戊二醛固定后也会变成2B5抗原阳性。然而，到2至4细胞阶段，胚胎发展出了自身合成2B5抗原阳性细胞表面分子的能力。这种合成被衣霉素抑制，表明抗原位点涉及糖蛋白的糖成分。发现植入后胚胎和成年生殖道中用2B5抗体标记的组织范围与已知的SSEA-1单克隆抗体非常相似（索尔特和诺尔斯，1978年；福克斯等人，
