Protective efficacy of a recombinant herpesvirus of turkeys as an in ovo vaccine against Newcastle and Marek's diseases in specific-pathogen-free chickens

Development of an Effective Polyvalent Vaccine against both Marek's and Newcastle Diseases Based on Recombinant Marek's Disease Virus Type 1 in Commercial Chickens with Maternal Antibodies

“…In the poultry industry, four recombinant viruses (rFPV [1,5,8,14,18,25,31,34,35,59], rHVT [13,17,28,41,44,53], adenovirus [51], and rMDV1 [45,47,49,54,62]) that express foreign antigens of other avian pathogens (including NDV [14, 17, 24, 28-30, 35, 47, 53, 58], MDV [31,33,42,44,69], infectious bursal disease virus [1,5,13,18,19,51,62], avian influenza virus [2,3,5,56,59,61,65,66], avian leukosis virus [34], and avian reticuloendotheliosis virus [8]) have been developed, and these viruses showed significant vaccine efficacy against a variety of avian diseases. Further, rHVT, rMDV1, and rFPV expressing NDV antigens have been constructed and used to FIG.…”

“…(i) The viruses induce lifetime protection against MD with just one vaccination (39), (ii) the viruses have a natural host range limited to avian species, and therefore, the vectors would be safe for other domestic animals and people working in the poultry industry, and (iii) techniques for generating recombinant MDVs have been well established (45,49). Among the vaccine viruses, HVT has been used worldwide both as live vaccine and polyvalent vaccine vector (13,17,28,29,41,42,53). However, attenuated MDV1 strains, such as C/R6 (G. F. de Boer, J. M. A. Pol, and S. H. M. Jeurissen, Proc.…”

Protective Immunity against Eimeria acervulina following In Ovo Immunization with a Recombinant Subunit Vaccine and Cytokine Genes

“…Vaccination of eggs represents a promising avenue of delivery, and over the past 2 decades it has been shown to be a safe, effective, and convenient method of administering many different agents, including drugs, nutrients, immunogens, and genes (11,31). In ovo administration of protein-based, as well as live or attenuated, vaccines has been experimentally demonstrated to be an effective method of immunization against many different avian diseases and is routinely performed in the commercial broiler industry for selected pathogens (6,21,30,(35)(36)(37)(38)44). In the case of coccidiosis, in ovo vaccination using live Eimeria parasites (45,46) has shown promising results for disease management in production settings, although a drawback to any immunization protocol using viable coccidia is posthatch fecal shedding of infectious oocysts.…”

Progress toward the development of polyvalent vaccination strategies against multiple viral infections in chickens using herpesvirus of turkeys as vector

“…Such recombinant HVT-based vaccines confer excellent and long-lasting simultaneous protective immunity in chickens against more than one pathogen, following the "one stone, two birds" principle. [21][22][23][24] However, these HVT recombinants have been prepared using conventional genomic recombination techniques, which are extremely time-consuming and laborintensive. Additionally, it has never been possible to recover purified recombinant viruses through plaque selection methods, leading to decreased immunogenicity after continuous passage in cultured cells.…”