Comparison of antigenicity between recently isolated bovine rotaviruses A and vaccine strains by cross-neutralizing antibody tests and their significance for immunization

Figures

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  Fig. 1.. Plaque formation by three representative isolated rotaviruses A cloned strains in MA104 cells. Three isolates were selected by their plaque growth and size. When virus stocks were assayed by plaque method, AH1041 showed large plaques and AH1207 only small size plaques, while AH1471 showed medium plaques predominantly, but also small plaques. Finally, three plaques formed by from each isolate were chosen and named AH1041, AH1207 and AH1471, respectively.

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  Fig. 2.. Phylogenetic tree of (a) G6, G8, G10 genotypes and (b) P[1], P[5], P[11] genotypes constructed using MEGA-X based on nucleotide sequences of the VP7 and VP4 coding genes for representative Japanese bovine rotaviruses A strains (closed circle). The GeneBank accession numbers of the strains are indicated. For the construction of the phylogenetic trees, the evolutionary history was inferred using the maximum-likelihood method with best-fit models based on the general time reversible model with discrete gamma distribution and invariant sites by 1,000 bootstrap replicates.

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  Fig. 3.. Neutralizing antibody titers against rotaviruses A strains in plasma of 1- to 6-week-old calves from farm A. Four bovine RVA strains with different G and P genotypes (3 RVA strains isolated in the present study and Shimane strain with G6P[1]) have been used in neutralization assay. Plasma samples from 25 individual calves of 8 to 42 days old were used for neutralization assay against four representative bovine RVA strains. The virus neutralizing antibody titers were shown as the reciprocals of the serum dilutions showing the 50% plaque reduction.