XmAbCD40 has enhanced binding affinities for human and mouse FcγRs (Kd values in nM)
| . | Human . | Mouse . | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FcγRI . | FcγRIIa 131R . | FcγRIIa 131H . | FcγRIIb . | FcγRIIIa 158F . | FcγRIIIa 158V . | FcγRI . | FcγRII . | FcγRIII* . | FcγRIV . | |
| XmAbCD40 | 0.053 ± 0.007 | 63 ± 2 | 81 ± 7 | 83 ± 29 | 13 ± 0 | 2.1 ± 0 | 1.6 ± 0 | 100 ± 0 | 13 ± 4 | 0.23 ± 0 |
| Anti-CD40 IgG1 | 0.16 ± 0.03 | 620 ± 190 | 610 ± 170 | 1600 ± 1200 | 690 ± 190 | 170 ± 20 | 110 ± 0 | 1100 ± 0 | 4 ± 1 | 21 ± 0 |
| Fold† | 3.0 | 9.8 | 7.5 | 19 | 53 | 81 | 69 | 11 | 3 | 91 |
| . | Human . | Mouse . | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FcγRI . | FcγRIIa 131R . | FcγRIIa 131H . | FcγRIIb . | FcγRIIIa 158F . | FcγRIIIa 158V . | FcγRI . | FcγRII . | FcγRIII* . | FcγRIV . | |
| XmAbCD40 | 0.053 ± 0.007 | 63 ± 2 | 81 ± 7 | 83 ± 29 | 13 ± 0 | 2.1 ± 0 | 1.6 ± 0 | 100 ± 0 | 13 ± 4 | 0.23 ± 0 |
| Anti-CD40 IgG1 | 0.16 ± 0.03 | 620 ± 190 | 610 ± 170 | 1600 ± 1200 | 690 ± 190 | 170 ± 20 | 110 ± 0 | 1100 ± 0 | 4 ± 1 | 21 ± 0 |
| Fold† | 3.0 | 9.8 | 7.5 | 19 | 53 | 81 | 69 | 11 | 3 | 91 |
FcγR binding was determined by Biacore analysis. Equilibrium dissociation constants (Kd) were obtained from Langmuir fits of the Biacore data. Results are from duplicate experiments and are mean ± SD. The anti-CD40 Fc-KO (G236R/L328R) showed no detectable binding to any human or mouse FcγRs.
Sensorgrams cannot be fit using a simultaneous group fitting. Kd was determined using separate dissociation (kd) and association (ka) models of the Biaevaluation software (Version 4.1).
Increase in binding affinity (Ka XmAbCD40/Ka anti-CD40 IgG1); Ka = 1/Kd.