|Maree, Francois - ONDERSTEPOORT VET. INST.|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2005
Publication Date: June 19, 2005
Citation: Maree, F.F., Rieder, A.E. 2005. Recombinant Engineered sat1 Foot-and-Mouth Disease Virus as an Approach to Investigate Receptor Usage and Growth Determinants of Outbreak Strains. XIIIth Meeting of the European Study Group for the Molecular Biology of Picornaviruses. p 123. Technical Abstract: Foot-and-mouth desease (FMD), a highly contagious viral disease of cattle, sheep, pigs and other cloven-hoofed animals has recently caused devastating epidemics world-wide. In the three South African Territories (SAT) types of foot-and-mouth disease virus (FMDV), the aetiological agent display great genetic and antigenic diversity; a likely consequence of the high mutation rate and independent evolution of these viruses in different geographic localities. Effective control of the disease in southern Africa relies in part on strategic vaccination of susceptible animals. For vaccination to be effective, it requires the incorporation of vaccine strains representative of strains prevalent in the locality in question. Adaptation of these viruses can be a difficult and tedious process, with low amounts of stable antigen obtained mainly as a result of lack of information on receptor usage and performance of these field strains in tissue culture. To circumvent this we have engineered an infectious genome-length cDNA copy of a SAT1 vaccine strain, SAR/9/81, and derived chimeric genomes to investigate the receptor usage and tropism characteristics of unknown field strains. This was accomplished by replacing the relevant coding region for the receptor recognition site by that of the field strain in question. FMD viral RNA, transfected into BHK cells, is infectious, which make genetically engineering of new viruses from "in vitro"-generated RNA molecules possible. The chimeric SAT viruses retained the desirable biological properties of the parental strain, while encoded replication determinants and cell-receptor binding characteristics of the field strains. Viable virus recovered from the genome-length clone displayed immunological and growth properties that corresponded to that of parental SAR/9/81 virus.