Comparative immunogenicity of 3 recombinant Adenovirus-based immunocontraceptive vaccines with different hormone targets

Abstract

The ever-expanding stray dog population is a major concern in many developing countries. Stray dogs are unfairly exposed to inadequate living conditions, starvation, neglect and harassment. They also burden an area by lowering its sanitation, safety and appeal. Many diseases (such as rabies) are spread by stray dogs, endangering humans and other animals. This highlights the importance of dog population management. There are many different forms of dog population management but immunocontraceptive vaccines seem to be the most promising in terms of cost, resource efficiency, practicality and targeting the source of the problem. In this project, two different immunocontraceptive vaccines (AdGnRH-TT and AdKP-TT), each expressing a different reproductive hormone target (kisspeptin or GnRH) couped to a partial tetanus toxin gene to enhance immunogenicity, were developed. Previously our research group constructed a dual hormone target immunocontraceptive vaccine (AdGKT) which contained the kisspeptin, GnRH and partial tetanus toxin genes. All three of these vaccines were administered to mice and the anti-hormone antibody titres quantified to determine which vaccine was the most immunogenic and should be used as the candidate vaccine to test in the target species, namely domestic dogs. It was found that the AdGKT vaccine was by far the most immunogenic candidate, yielding far greater, statistically significant anti-hormone antibody titres compared to the two single hormone target vaccines, which in fact led to no seroconversion in mice. Therefore, the AdGKT vaccine will be used in future trials involving dogs.