Technology Details:
Equine herpesvirus 1 (EHV1) causes multifaceted infections in equines including abortion storm in mares, respiratory disease and neurological disorder. The disease is endemic worldwide in all equine populated countries including India. Major way to control the disease spread is through a strong vaccine program along with biosecurity measures at farm(s). The current EHVl vaccines comprise inactivated virus vaccine for control of abortion in pregnant mares and respiratory disease; and modified live vaccine (MLV) for prevention of respiratory disease. However, none of the available vaccines are able to provide strong and long-lasting immunity to prevent EHV1 associated abortions, febrile disease, nasal virus shedding and viremia completely. An ideal vaccine against EHV1 should provide strong and long-lasting immunity against the virus and live vaccines are good option. Various live vaccines are available with naturally attenuated virus strains (RacH, KyA) and few have been generated by creating mutants in laboratory. The bacterial artificial chromosome (BAC) technology based platforms are widely used for the cloning of large viral genome; faithful clonal maintenance of the virus genome in E. coli in single copy number and associated mutagenesis strategies help in easy manipulation of the viral genomes. This technology has been successfully implemented in EHV1 functional research and development of live attenuated vaccines. The gE and IR6 and other glycoproteins encoded genes have been exploited by us for generation of attenuated EHV1 vaccine production for their role in virulence of the virus.:
In the current technology we have deleted the important virulence associated genes (gE and IR6) from the EHV1 genome and developed a novel vaccine vector construct for generation of attenuated modified live vaccine candidate for stimulating both humoral and cell mediated immune responses. This double gene deleted EHV1-BAC construct was used to generate mutant EHV1 virus for development of live attenuated vaccine candidate against EHV1. The utility of the double gene deleted recombinant EHV1 generated from the BAC construct has been shown by evaluating protective efficacy for generating immune responses in mouse model challenge studies. Based on results from in vitro experiments and mouse model studies, two genes deletion mutant is promising vaccine candidate and has potential to be used as a vaccine for equines for horses/ponies for prevention of respiratory disease and abortions. This vaccine will serve as an alternative for control of the disease.