Binding avidities and neutralization potencies of GR human anti-E MAbs. (A) Binding curves and Kd values for 12 and 20 GR human anti-E MAbs derived from primary and secondary DENV infections, respectively, were determined by a DENV1 virion-capture ELISA. The FRNT50 values against DENV1 are shown on the right. The two-tailed Mann-Whitney test was used to compare the two groups. (B to D) Binding curves, Kd values, and FRNT50 values against DENV1 for three GR human MAbs recognizing the same epitope involving four FL residues (W101, G106, L107, and F108) (B), seven GR human MAbs recognizing three FL residues (three residues among W101, F108, G106, and L107) as an epitope (C), and six GR human MAbs recognizing both FL residues and bc loop residues as an epitope (D). Data are means (with standard deviations for binding curves) for duplicates from one representative experiment of two. Blue closed symbols, MAbs derived from primary DENV infections; red open symbols, MAbs derived from secondary DENV infections.