Fig. 1: Epitope-guided selection of tight binding antibodies for hCXCR2.

a Schematic illustration of antibodies selected by phage panning based on the IL-8 epitope on the extracellular N-terminus of hCXCR2 (pepN48). b Binding affinity measurements of two combinatorial antibodies, abN48-IgG1 and abN48-2-IgG1 by SPR assay on a Biacore T200. Curves in the sensorgram plots represent a range of concentrations of antibody solutions: 0.1, 0.5, 1, 2, 5 and 10 nM for abN48-IgG1 and 0.1, 0.2, 0.5, 1, 2, and 5 nM for abN48-2-IgG1. c HDX exchange for pepN48 in the presence of abN48-IgG1 (upper panel) or abN48-2-IgG1 (lower panel) as compared to free pepN48. The percentage difference in deuterium uptake values at different labeling time points is represented as heatmap, with light gray indicating no significant changes, red indicating increase, and blue indicating decrease in HDX exchange rates. d Crystal structure of pepN9-19 in complex with abN48-2 illustrating that the aromatic side chains of Phe14 and Trp15 from pepN9-19 snugly fit into a cavity formed by the antibody CDR loops. The light and heavy chains of abN48-2 are shown as light and dark gray surfaces, respectively. The CDR loops of the heavy chain and light chain are depicted as red and green cartoons respectively and the surface representation was rendered transparent to show the location of the CDR loops. The backbone of bound pepN9-19 is depicted as a yellow tube with the side chains of critical residues as stick models. e Close-up view of the interface between pepN9-19 and abN48-2. Key residues involved in the antibody-antigen interface are shown as stick models and color-coded as following: light gray (light chain residues), dark gray (heavy chain residues), and yellow (pepN9-19 residues). Polar and electrostatic interactions are indicated with black dashed lines. The CDRs residues are labeled following Kabat numbering.