Immunization with a DNA vaccine of testis-specific sodium-hydrogen exchanger by oral feeding or nasal instillation reduces fertility in female mice

ObjectiveTo investigate the effect of immunization with a DNA vaccine of testis-specific sodium-hydrogen exchanger (tsNHE) via oral feeding or nasal instillation on fertility in female mice and to look at its potential mechanism.DesignProspective, research study.SettingInstitution-affiliated research laboratory.Animal(s)Sexual mature BALB/c mice.Intervention(s)Female mice immunized orally or nasally with the DNA vaccine at 2-week' intervals.Main Outcome Measure(s)Number of newborns and fertility rate of the vaccinated female mice were scored.Result(s)We identified a novel testis-specific sodium-hydrogen exchanger, tsNHE, which is localized to the principal piece of sperm flagellum. Immunization of female mice with the tsNHE DNA vaccine via oral feeding or nasal instillation statistically significantly decreased fertility rate and the newborn numbers compared with the controls. The antiserum or vaginal fluid from the tsNHE cDNA vaccinated female mice could specifically recognize the principal piece of sperm tail and triggered sperm agglutination. The antibodies also showed a statistically significant inhibitory effect on in vitro sperm motility and fertilization.Conclusion(s)The sodium-hydrogen exchanger might be an excellent target molecule for developing a new contraceptive.