||AHRI report No.46
Study on the Genetic Variation of Porcinophilic Foot and Mouth Disease Virus in Taiwan
Animal Health Research Institute, Council of Agriculture, Executive Yuan
||YW Huang*, YL Lin, PQ Sun, YY Ke, SH Tsai
||A purified O/TAW/97 foot-and-mouth disease virus (FMDV) was serially passaged in baby hamster kidney (BHK-21) cells for a total of 150 times. The VP1 gene from each passage was amplified using reverse transcription-polymerase chain reaction (RT-PCR). The RT-PCR products were sequenced. Nucleotide and deduced amino acid sequences were compared among those of known virus strains. The results showed that a total of 10 and 7 mutations were found in VP1 nucleotide and deduced amino acid sequences of passaged FMDV between the 16th generation and the 150th generation, respectively. The variation rates of nucleic acid and deduced amino acid sequences in the progeny of passaged FMDV were 0.2 to 1.3 and 0.5 to 2.9, respectively. However, the mutations did not occur at the major antigenic sites. On the other hand, based on a phylogenetic tree analysis of VP1 sequences of passaged and isolated Taiwanese FMDVs, the passaged FMDVs displayed greater similarity to the FMDV O/TAW/205/98 vaccine strains than to the Taiwanese FMDV isolates. Furthermore, the resulting correlation of the vaccine virus and the wild virus (r1 values) were between 0.4 and 0.81, respectively, indicating that the FMDV O/TAW/205/98 vaccine strain should provide a certain level of protection against passaged field FMDV isolates. Results revealed that even at the constraints condition, the FMDV mutation rate in vitro culture lacking neutralization antibodies, was not comparable to that in vivo with neutralization antibodies.
||Foot and mouth disease virus, Genetic variation, Passage