Nasal immunization with mature sperm specific antigen CD52 for developing a contraceptive vaccine

据报道，人类CD52是一种糖基磷脂酰肌醇锚定蛋白，存在于淋巴细胞、单核细胞、男性生殖道、射精精子和精浆中。这种抗原诱导抗体导致女性不孕，并损害精子活力。本研究通过小鼠mrt-CD52是否在小鼠体内产生抗体的模型实验来阐明mer-CD52抗原引起的不育，同时该抗原也可用于避孕疫苗的开发。[方法]从ICR小鼠输精管制备mrt-C52，用完全的弗氏佐剂注射于雌雄C57BL小鼠。另一种方法是用霍乱毒素b经鼻途径免疫小鼠，采用ELISA、western blotting和免疫荧光染色检测抗体产生情况。通过精子固定化试验、体外受精和交配实验，对抗体的生物学效应进行了研究。[结果]纯化小鼠mrt-CD52经皮下免疫，雌雄小鼠均产生自身抗体和同效抗体。所有产生的抗体都不与mrt-CD52的肽部分发生反应，这表明碳水化合物部分具有免疫原性。抗体在补体存在下固定小鼠精子，但不抑制体外受精或体内生育。【讨论】结果提示mrt-C52抗体可能导致部分不孕妇女不孕。在女性生殖道内产生IgA类抗体，用于研制mrt-CD52粘膜免疫避孕疫苗还需进一步实验。

Human CD52 has been reported to be a glycosylphosphatidylinositol anchor protein that is present in lymphocytes, monocytes, male reproductive tracts, ejaculated sperm and seminal plasma. This antigen induces antibodies causing infertility in women and impairs sperm motility. The present study is conducted as a model experiment to examine whether mouse mrt-CD52 produces antibodies in mice to clarify mer-CD52 antigen cause infertility and also this antigen is available for contraceptive vaccine development. [Methods] mrt-C52 was prepared from ICR mouse vas deferens and injected in male and female C57BL mice with complete Freund's adjuvant. Alternatively, mice were immunized by intranasal route with cholera toxin B. Antibody production was assessed by ELISA, western blotting and immunofluorescent staining. Biological effects of the antibodies were examined by sperm immobilizing test, in-vitro fertilization and mating experiments. [Results] Male and female mice produced auto- and iso-antibodies by immunization with purified mouse mrt-CD52 by a subcutaneous route. All the produced antibodies did not react to the peptide portion of mrt-CD52, suggesting that the carbohydrate moiety is immunogenic. The antibodies immobilized mouse sperm in the presence of complement but not inhibited in-vitro fertilization or in-vivo fertility. [Discussion] The results suggested that the antibody to mrt-C52 possibly cause infertility in some infertile women. Further experiment is necessary to produce IgA class antibody in female genital tracts for developing a contraceptive vaccine by mucosal immunization with mrt-CD52.