FIG 3.

N1-BR18 rNAs retain the antigenicity of multiple head domain epitopes. (A) Side view (left) and top view (right) of an N1 dimer (PDB accession number 3NSS) showing the three epitopes that are recognized by mAbs CD6 and 4C4 and the broadly reactive mAbs 1H5 and 4E9. The NA active-site residues 118, 151, 152, 224, 276, 292, 371, and 406 are shown in yellow. (B) N1-BR18 rNAs were readily bound by mAbs CD6, 4C4, 1H5, and 4E9. Binding was measured by a sandwich ELISA, in which mAbs CD6, 4C4, and 1H5 were used to capture the rNAs and the HRP-conjugated mAbs 4E9 (4E9-HRP) and 4C4 (4C4-HRP) were used for detection. N2-specific mAb B10 and an rNA from A/Minnesota/11/2010 (H3N2) were used as negative controls. rNAs were tested at 1 μg/ml. The data are the means ± SD from three technical repeats. (C) Serially diluted N1-BR18 rNAs were captured with mAb CD6 and detected with 4E9-HRP. The data are the means ± SD from three technical repeats. Purified BR18×WSN virus was included as a control.