Division of Medical Sciences, Boston University School of Medicine, Boston, MA 02118, United States.
Department of Medicine, Boston University School of Medicine, 670 Albany St. Rm 516, Boston, MA 02118, United States.
EBioMedicine. 2021 Jul;69:103478. doi: 10.1016/j.ebiom.2021.103478. Epub 2021 Jul 10.
Approximately 40% of human pregnancies are unintended, indicating a need for more acceptable effective contraception methods. New antibody production systems make it possible to manufacture reagent-grade human monoclonal antibodies (mAbs) for clinical use. We used the Nicotiana platform to produce a human antisperm mAb and tested its efficacy for on-demand topical contraception.
Heavy and light chain variable region DNA sequences of a human IgM antisperm antibody derived from an infertile woman were inserted with human IgG constant region sequences into an agrobacterium and transfected into Nicotiana benthamiana. The product, an IgG mAb ["Human Contraception Antibody" (HCA)], was purified on Protein A columns, and QC was performed using the LabChip GXII Touch protein characterization system and SEC-HPLC. HCA was tested for antigen specificity by immunofluorescence and western blot assays, antisperm activity by sperm agglutination and complement dependent sperm immobilization assays, and safety in a human vaginal tissue (EpiVaginal™) model.
HCA was obtained at concentrations ranging from 0.4 to 4 mg/ml and consisted of > 90% IgG monomers. The mAb specifically reacted with a glycan epitope on CD52g, a glycoprotein produced in the male reproductive tract and found in abundance on sperm. HCA potently agglutinated sperm under a variety of relevant physiological conditions at concentrations ≥ 6.25 µg/ml, and mediated complement-dependent sperm immobilization at concentrations ≥ 1 µg/ml. HCA and its immune complexes did not induce inflammation in EpiVaginal™ tissue.
HCA, an IgG1 mAb with potent sperm agglutination and immobilization activity and a good safety profile, is a promising candidate for female contraception.
This research was supported by grants R01 HD095630 and P50HD096957 from the National Institutes of Health.
大约 40%的妊娠是意外的，这表明需要更可接受的有效避孕方法。新的抗体生产系统使得制造用于临床用途的试剂级人源单克隆抗体（mAb）成为可能。我们使用烟草平台生产了一种人抗精子 mAb，并测试了其用于按需局部避孕的效果。
将从不孕妇女中获得的人 IgM 抗精子抗体的重链和轻链可变区 DNA 序列与人类 IgG 恒定区序列一起插入农杆菌，并转染到烟草中。该产物是一种 IgG mAb[“人避孕抗体”（HCA）]，通过 Protein A 柱进行纯化，并使用 LabChip GXII Touch 蛋白质特征系统和 SEC-HPLC 进行 QC。通过免疫荧光和 Western blot 测定法测试 HCA 的抗原特异性，通过精子凝集和补体依赖性精子固定测定法测试抗精子活性，并在人阴道组织（EpiVaginal™）模型中测试安全性。
获得了浓度范围为 0.4 至 4 mg/ml 的 HCA，并且包含>90%的 IgG 单体。该 mAb 特异性地与 CD52g 上的糖基表位反应，CD52g 是一种在男性生殖道中产生的糖蛋白，在精子中大量存在。HCA 在浓度≥6.25μg/ml 时在多种相关生理条件下有效地凝集精子，并在浓度≥1μg/ml 时介导补体依赖性精子固定。HCA 及其免疫复合物在 EpiVaginal™组织中不会引起炎症。
HCA 是一种 IgG1 mAb，具有强大的精子凝集和固定活性以及良好的安全性，是女性避孕的有前途的候选药物。
这项研究得到了美国国立卫生研究院 R01 HD095630 和 P50HD096957 资助。
