Fine mapping of a continuous epitope on VP7 of bluetongue virus using overlapping synthetic peptides and a random epitope library.

Two complementary techniques have been used to delineate an epitope on VP7 of bluetongue virus. Two MAbs (F10 and D11), both of which bound within a region spanning amino acids 255 to 274 in the 349 amino acid protein, were used to probe overlapping synthetic peptides covering this region. A pentapeptide, QYPAL, and a hexapeptide, QY-PALT (amino acids 259-264), preferentially bound both MAbs. MAb F10 also reacted with a heptapeptide (TAEIFNV) immediately adjacent to QYPALT. The MAbs were also used to affinity-purify fusion phages from a random hexapeptide library. All phage peptides selected were similar to QYPALT. Comparison of the peptides suggested that residues Q and P at positions 1 and 3 were critical for recognition. Some affinity-purified phages displayed the hexapeptide QYPSLL, which is similar to a sequence in VP7 of another orbivirus, epizootic hemorrhagic disease virus. This finding allowed a potentially cross-reactive site to be identified.