a and b, Representative SPR profiles of 2C8 and 3H5 Fabs, respectively, binding to recombinant EDIII. Varying concentrations of Fab were flowed over immobilized EDIII of DENV2. c, On/off rate map showing binding affinities and rate constants for 2C8 (blue) and 3H5 (orange) at pH 7.4 (circles) and pH 5.5 (squares). Log-scale plot of kd (y-axis) against ka (x-axis). In this plot, affinity (kd/ka) increases from bottom left to top right, resulting in iso-affinity diagonals (red dotted lines). d and e, ELISA binding assays of full-length 2C8 and full-length 3H5 (2C8-FL and 3H5-FL) measured at pH 7.4 and pH 5.5 as indicated. (f) ELISA binding assay of full-length 3H5 (brown) and 2C8 (light blue) and corresponding Fabs (orange and dark blue, respectively) to DENV2 virions. (g and h) Neutralization activities of Fabs and full-length antibodies (FL) of 2C8 (g) and 3H5 (h). Three technical replicates of all neutralization and ELISA assays were carried out and the data are shown as mean ± s.e.m.