Performing Department
Vet and Biom Sci
Non Technical Summary
Vaccines are the most effective strategy for prevention and control of livestock infectious diseases, and viral vectors are among the most promising platforms to administer the next-generation of veterinary vaccines. Viral vaccine delivery systems that have been developed and are currently in use in veterinary medicine, include poxviruses, herpesviruses, alphaviruses and paramyxoviruses. Their effectiveness is based on the ability of the vector to induce both arms of the immune system resulting in the production of antibodies and cellular cellular immune responses in target animal species. Additionally, vectored vaccines are usually safer than modified live vaccines, and most viral vectors offer a flexible platform that can be rapidly engineered into novel vaccine candidates.The goal of the study proposed here is to develop a multi-species vector platform for vaccine delivery in cattle and swine. Specific aims of the study are: 1) to develop an ORFV-based vector platform with enhanced immunogenicity and safety, 2) to construct recombinant ORFV vectors expressing protective antigens of important pathogens of cattle and swine, and 3) to evaluate the immunogenicity and protective efficacy of ORFV-based recombinant vectors in target animal species. A novel vector platform based on the recently characterized and highly immunogenic parapoxvirus Orf virus will be developed here. By using traditional viral genetic engineeringapproaches, a gene that contributes to the pathogenicity of ORFV will be removed from the ORFV genome. This platform will be used to generate recombinant vectors expressing the protective antigens of important viral pathogens of cattle (bovine herpesvirus 1, BoHV-1) and swine (swine influenza virus, SIV). Additional experimental approaches will include evaluation of the immunogenicity and protective efficacy of the ORFV vector platform following immunization-challenge experiments in target animal species. Serological and cell mediated immune responses elicited by immunization with ORFV vectors will be assessed by quantifying antigen/virus specific antibody levels cell effector and memory responses by flow cytometry, respectively.The proposed work will have a significant impact on animal health by providing a safe and highly immunogenic vaccine delivery platform for infectious disease prevention and control in livestock species. Availability of a multi-species vaccine delivery platform that allows rapid generation of novel vectored vaccine candidates may be highly effective to combat endemic, newly- or re-emerging infectious diseases that currently threaten, or may become a threat to, the US livestock industry.
Animal Health Component
100%
Research Effort Categories
Basic
25%
Applied
25%
Developmental
50%
Goals / Objectives
Orf virus (ORFV) has long been used in veterinary medicine as an immunotherapeutic agent due to its potent immunostimulatory properties. The goal of this study is to develop an ORFV-based vaccine delivery platform for use in livestock species.We hypothesize that deletion of genes encoding immunomodulatory/virulence proteins from the ORFV genome will result in a vector platform with enhanced immunogenicity and safety.The objectives of this study are:Objective 1:to develop an ORFV-based vector platform with enhanced immunogenicity and safety. The ORFV virus has been recently shown to be immunogenic in cattle and swine. Here we propose to develop a vector platform with increased safety and immunogenicity for use in these livestock species. Our approach will involve deletion of genes that encode for immunomodulatory proteins and that contribute to ORFV virulence.Objective 2:to construct recombinant ORFV vectors expressing protective antigens of important pathogens of cattle and swine.Objective 3:to evaluate the immunogenicity and protective efficacy of ORFV-based recombinant vectors in target animal species.These objectives are related to the program area of Animal Health and Disease. The work will significantly impact the priority areas of "disease prevention" through improved "vaccination, delivery systems and/or vaccines" for livestock. A multi-species vaccine delivery platform will allow rapid development of intervention strategies to combat endemic and/or emerging diseases that constantly threat the US livestock industry.
Project Methods
The goal of the current proposal is to develop a multi-species vaccine delivery platform with increased safaty and immunoganicity in cattle and swine. The objectives of the project and the approaches that will be used to accomplish each objective are outlined below:Objective 1:To develop an ORFV-based vector platform with enhanced immunogenicity and safety.A novel vector platform based on the recently characterized and highly immunogenic ORFVΔ121will be developed. By using homologous recombination, an additional IMP-encoding gene that contributes to ORFV virulence and pathogenesis will be deleted from the ORFVΔ121vector genome to generate a double gene deletion recombinant vector. This platform will be used as the parental virus to generate recombinant vectors expressing the protective antigens of important viral pathogens of cattle and swine.Objective 2:To construct recombinant ORFV vectors expressing protective antigens of important pathogens of cattle and swine.The recombinant double-gene deleted virus generated in Objective 1 will be used as backbone to insert protective antigens of important pathogens of cattle (bovine herpesvirus 1; BoHV-1) and swine (swine influenza; SIV). The protective antigens of BoHV-1 and SIV will be inserted into the ORFV backbone by homologous recombination and resultant recombinant viruses will be characterizedin vitro. Correct insertions of heterologous genes will be assessed by complete genome sequenging and protein expression will be investigated by using western blots and immunofluorescence assays.Objective 3:To evaluate the immunogenicity and protective efficacy of ORFV-based recombinant vectors in target animal species. The immunogenicity and protective efficacy of the newly developed recombinant viruses (Objetive 2) will be investigated in cattle and swine. Initially, each animal species will be immunized with the corresponding ORFV-based contructs (ORFV-BHV1, cattle; and ORFV-SIV, swine) and the immune responses elicited by the immunization will be assessed by serological and CMI assays. Following immunization, animals will be challenged with BHV-1 or SIV and the protective efficacy of the vaccines will be evaluated by following clinical and virological parameters post-challenge infection.