Assignment of the Genome Segment Coding for the Neutralizing Epitope(s) of Orbiviruses in the Great Island Subgroup (Kemerovo Serogroup)

Reassortant viruses were produced from high-frequency recombination events between temperature-sensitive (ts) mutants of Broadhaven (BRD) (S. R. Moss and P. A. Nuttall, Virus Res. 4, 331-336, 1986) and Wexford (WEX) viruses, two serotypes in the Kemerovo serogroup of orbiviruses. The parental origin of each of the 10 genomic segments comprising each reassortant was determined by polyacrylamide gel electrophoresis. Comparison of neutralization titers with the results of genomic dsRNA analyses revealed that genome segment 5 codes for the neutralizing epitope(s). Kemerovo group viruses therefore differ from orbiviruses of the bluetongue serogroup in which segment 2 codes for the neutralizing epitopes (M. J. Grubman, J. A. Appleton, and G. J. Letchworth, Virology 131, 355-366, 1983; J. Kahlon, K. Sugiyama, and P. Roy, J. Virol. 48, 627-632, 1983). Results also indicated that the ts lesions in mutants of recombination groups II, III, and VI were in segments 1, 5, and 4, respectively. Reassortment of segments 2 and 10 appeared to be nonrandom, and evidence of possible "linkage" was obtained for segments 3 and 9.