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Research Project: Research Supporting Workforce Development for the National Bio-Agro Defense Facility: Development of CSF Subunit Vaccines

Location: Foreign Animal Disease Research

Project Number: 3022-32000-063-005-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2018
End Date: Dec 31, 2023

Objective:
This research project will provide scientific information and countermeasures to control and eradicate the priority foreign animal disease, Classical Swine Fever (CSF). E2 is the most immunogenic of the CSFV proteins and carries most of the epitopes eliciting virus neutralizing antibodies, which mediate protection. Through epitope mapping, we will identify specific monoclonal antibodies which can be used to develop mutant CSF vaccine candidates. Specific objectives include: 1. Conduct epitope mapping recognized by a novel set of monoclonal antibodies specific to CSFV major structural protein E2. 2. Develop recombinant CSFV having deleted epitopes recognized by the monoclonal antibodies identified in objective 1.

Approach:
1. The set of E2 specific monoclonal antibodies (E2mAbs) per determined by KSU, will be analyzed to determine the amino acid residues in E2 recognized by each of the E2mAb. Mapping will be conducted to identify amino acid residues in viral proteins interacting with host proteins. A library of the E2 protein will be created that will cover the full-length sequence of the protein and should allow for the identification of sequential areas of E2 recognized by each of the E2mAbs. Screening of E2mAbs reactivity will be performed to more accurately define the epitope recognized by the E2mAbs. 2. Based in the information produced in Objective 1, a set of recombinant CSFV mutants harboring specific mutatins in E2 will be created using reverse genetics. A set of recombinant viruses with a mutation in the epitope specifically recognized by some of the E2mAbs will be created in a recombinant attenuated virus that were rationally developed by ARS, PIADC as an experimental vaccine. Viable viruses will be grown, and checked in their inability to be recognized by the corresponding E2mAbs. Those viruses clearly not reacting will be further tested in vivo as a proof of concept DIVA functionality in pigs. Animals will be inoculated and the antibody response in sera will be evaluated in terms of testing the absence of pig antibodies reacting with the epitope under study.