The residue frequency map also reveals a major peak (FWHM at residues 392 to 480). This peak position is similar to that obtained using the mouse antisera (FWHM at residues 387-480), resulting in an almost identical structural frequency map (Fig. 4 , panels E and F, and Fig. S5 ). Thus, these antigenic regions are considered identical to R1 and R2 obtained from the mouse serum screening (Fig. 5 ).