DNA vaccine targeting GnRH-receptor reduces testosterone and induces testicular atrophy in mice

Reproductive control of invasive, feral, and domesticated animals is an urgent public health issue. Immunological vaccines are employed as an emerging strategy to target different components of the reproductive system, to achieve immunocastration. Successful use of immunogens against parts of the oocyte, spermatozoon, gonadotropin-releasing hormone (GnRH), and luteinizing hormone receptor (LHr) has been reported. In this work, a recombinant DNA vaccine was prepared (P2GnRHrP30) by the fusion of the first extracellular domain of the canine GnRH receptor (GNRHr) gene to the P2 and P30 tetanus toxoid epitopes. This construction was cloned in the pCI-NEO mammalian expression vector and evaluated as an immunocontraception DNA vaccine in male mice. The developed vaccine was demonstrated to be safe, and capable of reducing serum testosterone levels and causing testicular atrophy. Our work indicates that the first extracellular domain of the GnRHr gene may act as an immune target for reproductive control and potentially be used as a non-surgical sterilization procedure in mammals.