Progress 11/16/01 to 11/15/06
Outputs
Progress Report Objectives (from AD-416) Foot-and-Mouth Disease (FMD) is a highly contagious and economically devastating disease of cloven-hoofed animals caused by the Foot-and-Mouth Disease virus (FMDV). Six of the seven serotypes (type A, O, C, South African types (SAT) 1, 2, 3) have been isolated from the African continent where they are maintained by free-living maintenance hosts, primarily, the African buffalo. The three SAT types occur almost exclusively in sub-Saharan Africa and exhibit greater genomic and antigenic variation than types A, O and C. Current inactivated vaccines are often unable to control some lineages arising in these regions, posing the need for custom-made vaccines. The goal of this project is to utilize infectious cDNA technology to produce FMDV with improved biochemical/immunologenic properties for use as seed viruses in the production of chemically inactivated vaccine antigens specific for certain geographic localities. Approach (from AD-416) Substitution of the external capsid coding region of the SAT2FLC with the corresponding regions of SAT-1 and SAT-3 vaccine strains will be done, thus creating pSAT1/SAT2 and pSAT3/SAT2. In vitro RNA synthesis, transfection of baby hamster kidney cells with transcripts, and recovery of chimeras SAT1/SAT2 and SAT3/SAT1, will be conducted. SAT1/SAT2 and SAT3/SAT2 will then be compared and characterized against the parent SAT- 1 and SAT-3 viruses. The sera obtained from vaccinated animals will be evaluated for immunoreactivity through the use of virus neutralization testing. Additionally, we will adapt the existing SAT-2 genome-lenght clone of DNA transfection by insertion of cDNAs encoding ribozymes at the end of the cDNA copy of the viral genome. Significant Activities that Support Special Target Populations This report serves to document research conducted between the Onderstepoort Veterinary Institute (OVI), South Africa, and ARS, PIADC in a trust agreement. Additional details of this research can be found in the final report for the parent 1940-32000-043-00D, �Determination of the Molecular Basis for Re-emergence, Pathogenesis and Host Range of FMDV�. This research falls within the component 1: Biodefense Research of the NP- 103 National Program. The objective of this project was to overcome the problem of empirically deriving foot-and-mouth disease (FMD) virus strains for use as seed stocks in the preparation of FMD vaccines. We conducted studies to determine if genetic engineered FMD virus strains can be utilized as seed stocks for the preparation of SAT specifically designed vaccines. We have made progress in the investigation of growth determinant and receptor preferences of SAT viruses using biochemical, electron microscopy and genetic approaches during the length of this agreement. In addition we performed in vitro characterization of a panel of recombinant viruses carrying the capsid protein sequences of relevant outbreak strains of SAT2 and SAT3 viruses and generated infectious cDNA clones for a SAT1 vaccine and field viruses. The results indicated that not all the integrins are used with the same efficacy by the SAT serotypes for cell entry which correlates with results obtained previously for A and O type viruses. For all three SAT type viruses the alpha V beta 6 integrin are utilized with highest efficiency, followed by alpha V beta 3, while all SAT viruses showed poor recognition of alpha V beta 1. The moderate to poor use of the alpha V beta 3 integrin and the inability of alpha V beta 1 to mediate infection of the SAT serotypes is in contrast to the A and O type viruses. In addition we have examined the ability of parental and genetic engineered vaccine candidates to induce antibody responses in guinea pigs and the collection of data from this and efficacy test of vaccines in swine has been completed. A significant achievement of this study was the proof of concept on the utility of the recombinant cDNA technology to preserved the genetic and phenotypic properties of FMDV field and vaccine strains and the demonstration of alteration in the stability of virus particles when the virus acquire positively charged residues in the capsid and ability to bind to heparin-sulfate. The knowledge gained from this study will be useful for improving vaccine production platforms for FMD vaccines.
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 4d Progress report. This report serves to document incoming funds received in July 2006 from the Onderstepoort Veterinary Institute (OVI), Onderstepoort, South Africa, under a trust fund agreement between the USDA, ARS, Plum Island Animal Disease Center(PIADC), and OVI, South Africa. Additional information of this research can be found in the report for the parent CRIS 1940-32000- 043-00D, "Determination of the Molecular Basis for Re-emergence, Pathogenesis and Host Range of FMDV." These funds are intended to cover the PIADC costs of a collaborative research program under a specific cooperative agreement (58-1940-0-0122F) between ARS, PIADC and OVI. The objective of this project is to overcome the problem of empirically deriving foot-and-mouth disease (FMD) virus strains for use as seed stocks in the preparation of FMD vaccines. Specifically, we are determining if genetically engineered FMD virus strains can be utilized as seed stocks for the
preparation of SAT specifically designed vaccines. We have made progress in the investigation of growth determinant and receptor preferences of SAT viruses using biochemical, electron microscopy and genetic approaches during 2006 and plan to continue working on the characterization of prototype FMDV SAT viruses for vaccine purposes by genetic engineering. This research will be useful for improving vaccine production platforms for FMD vaccines. This research falls within the component 1: Biodefense Research of the NP-103 National Program.
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