Embryo vaccination of turkeys against Newcastle disease infection with recombinant fowlpox virus constructs containing interferons as adjuvants

Recombinant fowlpox viruses (rFPV) expressing the fusion and hemagglutinin- neuraminidase glycoproteins of Newcastle disease virus (NDV) as well as chi cken type I interferon (IFN) or type II IFN were used to vaccinate specific pathogen-free (SPF) turkeys in ovo. No significant changes in the hatchabi lity, survival rate, performance and weight gain were observed after vaccin ation with the rFPV vaccines in comparison to diluent-inoculated embryos. T he rFPV-NDV-IFN-II construct induced the onset of anti-NDV antibody product ion in SPF birds at one week post hatch, one week earlier than other vaccin e constructs. Three to five weeks post hatch, the turkeys were challenged w ith the neurotropic velogenic NDV strain Texas GB (NDV-GBTx). The rFPV-NDV- IFN-II construct was the most protective vaccine against NDV, rFPV vaccines significantly (p < 0.05) suppressed the mitogenic response of peripheral b lood leukocytes in vaccinated turkeys in comparison to placebo inoculated c ontrols at 25 days post vaccination. Birds vaccinated with rFPV-NDV-IFN-I c onstruct did not have an inhibition in the mitogenic response. (C) 1999 Els evier Science Ltd. All rights reserved.