FIG 5.

Chaotrope resistance increases with valency. Mono-, bi-, and tetravalent ligands were titrated against D7324-captured gp120 (JR-FL) in ELISAs. Binding, detected as luminescence (RLU), is expressed on the y axis as a function of ligand concentration (ng/ml) on the x axis. The potentially bi- or tetravalent binding of IgG and CD4-IgG2 is shown on the left, and the monovalent binding of Fabs and sCD4 on the right. The ligands were b6 IgG/Fab (A), b12 IgG/Fab (B), CD4-IgG2/sCD4 (C), and F24 IgG/Fab (D). Ligand binding after chaotrope (NaSCN) or control (PBS) treatment is represented by dashed and solid lines, respectively. The data points are the mean results from three intra-assay replicates, and the error bars show the SEM. Each plot is representative of ≥2 replicate experiments.