The majority of potent neutralizing antibodies recognize preF-specific sites. (A) Neutralization IC50s for the antibodies isolated from each donor repertoire. Data points are colored based on neutralization potency. Red and blue dotted lines depict motavizumab and D25 IC50s, respectively. N.N., non-neutralizing. (B) Percentage of neutralizing antibodies in each donor repertoire, grouped by potency. (C) Apparent binding affinities for preF and postF are plotted for each antibody and colored according to neutralization potency. (D) Neutralization IC50s are plotted for preF-specific, postF-specific, and cross-reactive antibodies. Red and blue dotted lines depict motavizumab and D25 IC50s, respectively. Black bar depicts median IC50.