Table 2.
Relative binding affinities determined by ELISA
| Group and variant | Binding relative to wt b12a |
||
|---|---|---|---|
| FcγRI | FcγRIIa | FcγRIIIa | |
| FcγRIIIa down-variants | |||
| S239A | 0.87 | 0.87 | 0.22 |
| S267G | 1.05 | 2.99 | 0.21 |
| K338A | 1.21 | 1.50 | 0.41 |
| FcγRIIIa up-variants | |||
| I332E | 1.21 | 3.19 | 7.32 |
| SD/IE | 1.29 | 5.99 | 31 |
| SD/IE/AL | 1.06 | 3.41 | 90 |
| FcγRIIa down-variants | |||
| D270E | 0.71 | 0.42 | 0.69 |
| R292A | 0.91 | 0.43 | 0.65 |
| S298A | 0.84 | 0.52 | 1.31 |
| FcγRIIa up-variants | |||
| G236A | 0.44 | 8.63 | 0.93 |
| SD/IE/GA | 0.91 | 49 | 66 |
a
Numbers represent the EC50 of wt b12/EC50s of b12 variants. EC50s (half-maximal effective concentrations) were calculated by fitting binding curves generated by plotting A450 of FcγR binding as a function of antibody concentration (n=2).