Recipient Organization
USDA-ARS, GENETICS AND PRECISION AGRICULTURE UNIT
810 HIGHWAY 12 EAST
MISSISSIPPI STATE,MS 39762
Performing Department
(N/A)
Non Technical Summary
Newavian metapneumoviruses (AMPVs) have recently been detected for the first time in the US and continue to spread impacting all the poultry sectors (broilers, layers, layer and broiler breeders, and turkeys). Vaccination is one of the most effective control measures and safe and efficacious vaccine is urgently needed. Live attenuated vaccines, which can induce strongimmune responses to protect birds from AMPV infection and disease, have been developed and used in other countries. However, the current method of developing live vaccine is tedious and time-consuming and, more importantly, the safety of live vaccines continue to be a concern. In this project, we willdevelop AMPV vaccines and vaccination regimenand evaluate the efficacy of candidate vaccines in chickens and turkeys. The main outcome of the proposed research will be the safe and efficacious AMPV vaccines and vaccination regimens that are readily applicable to US poultry. The vaccine platform and vaccination strategy developed in this study will be directly applicable to many economically important poultry diseases and contribute toreduction in economic loss by preventing the diseases.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
0%
Goals / Objectives
The primary goal of the projectis to develop safe and effective AMPV vaccines and vaccination regimens that can be easily applied to poultry in the US. Our long-term goal is to establish a flexible vaccine platform and vaccination strategy that is directly applicable to many economically important poultry diseases. Specific objectives are as follows:Objective 1: Develop live virus-vectored vaccines expressing major AMPV antigens.Objective 2: Evaluate the efficacy of candidatevaccines in specific pathogen free chickens.Objective 3: Evaluate vaccination regimens and immune correlates of cross-protective immunity in commercial birds.
Project Methods
We will develop live virus-vectored vaccines expressing two major AMPV antigens, fusion (F) and glycoprotein (G), and immunostimulatory genes utilizing safe and stable avian paramyxovirus type 1 (APMV-1) virus vector and herpesvirus vector developed at the Southeast Poultry Research Laboratory, USDA-ARS. AMPV and immunostimulatory genes will be de novo synthesized commercially and incorporated into the APMV-1 and herpesvirus vectors. The expression of the AMPV F and G protein in infected cells will be examined using an immunofluorescence assay. In addition, replication dynamics and pathogenicity of the recombinant virus will be determined using standard methods.Once the safety, stability, and in vitro replication of recombinant vaccines have been confirmed to be suitable as a vaccine candidate, the protective efficacy of each vaccine candidate will be compared in specific pathogen freechickens following different vaccination regimens.Experiments will be focused on evaluating vaccine efficacy based on the level of protection from manifesting different clinical signs and reduction in virus shedding, and assessment of a selected panel of immune correlates of protection. This objective will also involve the evaluation of pathogenicity of AMPV isolatesin birds and the establishment of an effective challenge model.Maternally derived antibody (MDA) can hinder the immune response to vaccination against different diseases in commercial poultry flocks. Although the presence of MDA has not been a concern for the herpesvirus-vectored vaccine, we will test the new herpesvirusvectored vaccine in commercial birds with MDA derived from MDV vaccination in breeders. In addition, different vaccination regimens that can be applied in commercial settings will be evaluated to overcome the MDA interference and further enhance the protective immunity. This objective will also extend the study to identify immune correlates of protection that are important for cross-protective immunity and demonstrate that the selected vaccine candidates in chickens are equally effective in commercial turkeys.