Identification of an amino acid on VP2 that affects neutralization of bluetongue virus serotype 10.

Genome segment 2, coding for the VP2 protein, of a neutralization resistant variant was compared to segment 2 of the bluetongue virus (BTV) serotype 10 parent from which the variant was derived. Full-length double-stranded cDNA of BTV segment 2 RNA, which was prepared by reverse transcription, was used as template to prepare overlapping subgenomic cDNA products by PCR. Purified PCR cDNA fragments were sequenced by the dideoxy chain termination reaction. Each base was determined an average of 3.7 times. Comparison of the sequence of segment 2 of the neutralization resistant variant with segment 2 of the parental virus showed two base changes, one of which resulted in a changed amino acid. This change was in a different region of VP2 than those previously reported in other neutralization resistant variants of BTV. In addition to this change, both the parental virus and the variant virus differed in two amino acids from the previously published sequence of VP2 of BTV serotype 10.