Fig. 7.

Measurements of MAb 19e binding kinetics with native versus mutant single-chain gp120-CD4 complexes. Sensorgrams represent SPR experiments (described in Materials and Methods) in which a concentration series of FLSC (red traces) or FLSC RASA (blue traces) was flowed over immobilized MAb 19e (A). For comparison, experiments with MAb 21c (B) were carried out in parallel. All binding conditions were tested in duplicate. Replicate sensorgram plots are shown. Blank experiments in which no antigen was used are shown as gray traces. Binding constants derived from the sensorgrams are tabulated (insets) along with calculated differences between FLSC and FLSC RASA binding parameters. The experiment was repeated with similar results.