Location: Foreign Animal Disease Research
Project Number: 8064-32000-056-12-S
Project Type: Specific Cooperative Agreement
Start Date: Oct 1, 2011
End Date: Mar 1, 2013
This research project seeks to evaluate native and modified forms of Classical Swine Fever (CSF) envelope proteins for their capacity to induce rapid protective immune responses against CSF virus. Specific objectives included the creation of recombinant baculoviruses to synthesize native and modified forms of CSFV strain Brescia E0, E1 and E2 glycoproteins. These baculovirus will be used to express massive amounts of these proteins in order to assess their immunogenicity in swine.
The assessment of each of the CSF virus structural proteins E0, E1 and E2 in the elicitation of a protective immune response in swine against CSF infection will be conducted. Genetic constructs will be designed and tested to determine levels of immunogenicity. Subsequent studies will be conducted to determine the levels of glycosylation needed to produce enhanced immune response. We will synthesize several forms of His-tagged CSFV E0, E1, or E2 envelope proteins from insect cells (Spodoptera frugiperda derived, Sf9) infected with recombinant baculoviruses. To assess the immunogenicity and antigenicity of these expressed proteins, forty lbs swine will be serially immunized with purified proteins followed by an intranasal challenge with 105 TCID50 of highly virulent strain Brescia (BICv) 7 days after the last inoculation. Antigenicity will be determined by measuring antibody response of immunized animals using commercially available ELISA tests and by virus neutralization. The ability of modified forms of CSFV envelope proteins to induce an antibody response will be compared relative to the antibody response induced by non-modified forms of the proteins. Immunogenicity will be determined by assessing swine survival after challenge with virulent CSFV s BICv relative to non-immunized control animals. Wild type and mutant genes of the three CSFV envelope proteins (E0, E1, and E2) will be synthesized. Recombinant baculoviruses will be produced and expressed and the resulting proteins purified. We will design and perform the antigenicity and immunogenicity studies in conjunction with the protein production. As a result of this research, CSFV proteins or combination of CSFV proteins that confer a robust immunity against CSFV will be identified. By using different CSFV proteins, both in their native as well as in their modified forms, their antigenicity and immunogenicity may be improved. These proteins will be safe and efficient against CSFV.