Location: Foreign Animal Disease Research
Project Number: 8064-32000-063-003-I
Project Type: Interagency Reimbursable Agreement
Start Date: Aug 10, 2018
End Date: Sep 30, 2022
ARS-PIADC has developed an antigenically marker live attenuated vaccine strain against Classical Swine Fever Virus called FlagT4G. This research project will allow for advanced development to include filing for the Select Agent Exclusion request to USDA, APHIS, the creation of a master seed to perform safety and efficacy studies, and the optimization of the DIVA accompanying test. Specific objectives include: 1. Creation of a FlagT4G master seed stock (MS). Swine kidney #6 (SK6) cells will be assessed for use in ms production. Stocks will then be produced per industry standards for registry in the Europe and the United States. 2. An assessment of the safety and efficacy studies of FlagT4G MS will be conducted inclusive of genetic stability, lack of toxicity and protective efficacy. Upon successful assessment, an application for exclusion of FlagT4G MS from the USDA, APHIS select agent list will be submitted.
1. Creation of a FlagT4G master seed stock. The FlagT4G master seed stock (MS) will be produced in qualified swine kidney #6 (SK6) cell line. An assessment will be conducted on the suitability of SK6 cells. The FlagT4G was developed and growth in SK6 cells. SK6 cells are not available of American Tissue Culture Collection or other commercial/public cell collection. SK6 at ARS, PIADC has been obtained from FLI, Germany. These cells need to be tested in their suitability as substrate to growth the FlagT4G MS. Assessment will be performed contracting a qualified commercial partner. SK6 cells will be adapted to growth in a bioreactor and further use to growth the FlagT4G MS stock, thus meeting regulatory requirements for registration in Europe and the United States. 2. FlagT4G MS will be assessed in its safety, immunogenicity and protective effect. In addition, it will tested in swine in terms of genetic stability, lack of toxicity and protective efficacy against challenge with virulent virus. Specific studies include a.) an assessment of the genetic stability in a reversion to virulence protocol following World Organization for Animal Health (OIE) specifications. The virus must remain completely attenuated and genetically stable after five successive passages in swine. FlagT4G MS will also be assessed b.) to show a lack of toxicity. The virus must not induce either local or systemic CSF-associated clinical signs and c.) the minimal protective doses of the FlagT4G MS will be determined in swine following OIE protocols. Different dilutions of the MS will be tested in pigs that will be further challenged with a virulent CSFV strain. This information will result in an assessment of the protective efficacy. Results obtained from these studies are needed for USDA, APHIS select agent exclusion.