Generation of a FHV-1 Viral Vaccine Against Gonadotropin Releasing Hormone for Immunocontraception of Felines

Abstract

With approximately 8.5 million unwanted cats euthanized in the U.S. annually, convenient, cost effective methods of sterilization are greatly needed. Current spay/neuter techniques, such as surgery and hormonal intervention, are not satisfying this need due to their high cost, significant expertise required, and the need for feral cats to be collected and brought into clinics for treatment. The aim of this research is to develop a safe contraceptive vaccine that could be delivered to the feral cat population in bait without compromising non-feline species. Feline Herpes Virus (FHV) is a feline specific virus. The USDA has approved the immunization of cats with an attenuated, non-pathogenic strain of FHV expressing foreign antigens. In our research, we have partially replaced Glycoprotein I of FHV to express a fusion protein of Flagellin (FliC), Enhanced Green Fluorescent Protein (EGFP), and Gonadotropin Releasing Hormone (GnRH). FliC has been shown to stimulate a heightened antibody response when antigens are expressed as fusion proteins with it. GnRH, a major reproductive hormone responsible for the development of testes and ovaries in felines, is the target of our vaccine vector. Expression of EGFP will allow tracking of the viral vector. The expression of the fusion protein (FliC-EGFP-GnRH) is expected to stimulate an antibody and cell mediated immune response directed towards feline GnRH, which will provide an immunocontraceptive effect specific to cats.