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Objective: To explore the contraceptive potential of the CatSper1 transmembrane domains and pore region in vitro.Design: In vitro study with human sperm and mouse fertilization.Setting: Andrology laboratory of an academic research center.Patient(s) and Animal(s): Normozoospermia and viripotent BALB/c mice.Intervention(s): The specific binding of an anti-CatSper1 IgG antibody (H-300) to CatSper1 was confirmed by Western blot and immunofluorescence. Sperm from humans and mice were incubated with H-300.Main Outcome Measure(s): The effects of H-300 on human sperm progressive motility, abnormal acrosome, hyperactivated motility, and mouse in vitro fertilization rates were analyzed.Result(s): A significant decline in sperm progressive motility was observed after 1, 2, and 4 hours of incubation with H-300; the change was mainly ascribed to the decline of fast progressive motility. Significant inhibition of the hyperactivated motility was observed after 5 hours of incubation with H-300. The incubation of mouse sperm with H-300 before insemination reduced the in vitro fertilization rate to 28% of control levels (72% inhibition).Conclusion(s): CatSper1 may be a potential target for immunocontraception, and the antibody may be a tool to study the function of ion channels in sperm in which relatively fewer methods can be applied. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the contraceptive ability of two B-cell epitopes in CatSper1. Design: In vivo study with mice. Setting: University laboratory animal service center. Animal(s): BALB/c mice. Intervention(s): Two predicted B-cell epitopes in the extracellular part of transmembrane domains and pore region of CatSper1 were synthesized to immunize male mice. Main Outcome Measure(s): Fertility, epididymal sperm function, and the presence of specific antibody in immunized males were investigated. Result(s): Significant reduction of fertility was observed in mating trial with no evident systemic illness or abnormal mating behavior. Epididymal sperm of epitope-immunized males exhibited impaired ability to fertilize eggs in vitro, and showed sperm agglutination in some animals, while presenting no changes in sperm viability or progressive motility. High titer of antibodies was induced in the sera, and the antibodies’ specificity was confirmed. The binding of the antibodies to epididymal sperm of epitope-immunized males was observed. Conclusion(s): CatSper members could be the effective and viable targets for immunocontraception. These two epitopes in CatSper1 share high identity between mouse and human and may be effective for fertility regulation in humans. [ABSTRACT FROM AUTHOR]