Table 3.
Binding affinities of reverse-engineered 3H3 and LOB12.3 Fab variants to CD137.
| Fab sample | ka (x 105M−1s−1) | kd (x 10−3s−1) | KD (nM) |
|---|---|---|---|
| LOB12.3-Fab1 (VH-I100c) | 4.29 | 3.68 | 8.60 |
| LOB12.3-Fab2 (VH-L100c) | 5.29 | 3.75 | 7.06 |
| LOB12.3-Fabp | 4.50 | 3.74 | 8.30 |
| 3H3-Fab1 (VH-I29) | 25.4 | 4.63 | 1.82 |
| 3H3-Fab2 (VH-L29) | 28.8 | 4.83 | 1.68 |
| 3H3-Fabp | 22.1 | 4.51 | 2.05 |
LOB12.3-Fab1, -Fab2 and 3H3-Fab1, -Fab2 were reverse-engineered Fab variants, while LOB12.3-Fabp and 3H3-Fabp were Fabs derived by partial proteolysis of the parental (i.e., commercially obtained) IgGs. Standard errors for fitting of data to a 1:1 binding model were less than one unit in the third significant digit for all computed ka, kd and KD values.