Identification of an antibacterial polypeptide in mouse seminal vesicle secretions

Kazunori Morohoshi, Takeo Yamazaki, Keiji Kito, Ban Sato, Woojin Kang, Taku Hibino, Manabu Yoshida, Kaoru Yoshida, Teruaki Iwamoto, Mitsutoshi Yamada, Kenji Miyado, Natsuko Kawano

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


In both men and women, pathogenic bacteria enter the reproductive tract and cause harmful symptoms. Intrauterine and oviductal inflammation after copulation may have severe effects, such as infertility, implantation failure, oviduct obstruction, and robust life-threatening bacterial infection. Human seminal plasma is considered to be protective against bacterial infection. Among its components, Semenogelin-I/-II proteins are digested to function as bactericidal factors; however, their sequences are not conserved in mammals. Therefore, alternative antibacterial (bactericidal and/or bacteriostatic) systems may exist across mammals. In this study, we examined the antibacterial activity in the seminal plasma of mice lacking a gene cluster encoding Semenogelin-I/-II counterparts. Even in the absence of the majority of seminal proteins, antibacterial activity remained in the seminal plasma. Moreover, a combination of gel chromatography and liquid chromatography coupled with tandem mass spectrometry revealed that the prostate and testis expressed 4 protein as a novel antibacterial (specifically, bacteriostatic) protein, the sequence of which is broadly conserved across mammals. Our results provide the first evidence of a bacteriostatic protein that is widely present in the mammalian seminal plasma.

Original languageEnglish
Article number103436
JournalJournal of Reproductive Immunology
Publication statusPublished - 2021 Nov


  • Antibacterial activity
  • Bacteriostasis
  • PATE4
  • SVS7
  • Seminal plasma
  • Seminal vesicle secretion

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Reproductive Medicine
  • Obstetrics and Gynaecology


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