Table 1. Comparison of KinExA-determined affinities for various mAbs binding their purified recombinant and native serum antigens.
|
mAb’s activity (%)a
|
recombinant antigen
|
human serum
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Figure | mAb | antigen | CFCA | LCM | KD (pM) | n | KD (pM) | antigen conc.b (nM) | n | KD ratioc |
| 2A | J16 | PCSK9 | 44 | 47 (45-51) | 3.4 (2.5-4.5) | 2 | 3.4 (1.2-6.6) | 1.1 (0.85-1.3) | 5 | 1.0 |
| 2B | 19F7 | PGRN | nd | 41 (35-51) | 335 (265-430) | 2 | 364 (264-483) | 1.5 (0.92-2.2) | 3 | 1.1 |
| 2C | 21B8 | FABP4 | nd | 75 (68-83) | 54 (43-68) | 2 | 47 (32-60) | 1.3 (0.89-1.8) | 3 | 0.9 |
| 3A | J17 | PCSK9 | 57 | 53 (47-61) | 64 (50-83) | 2 | 38 (30-47) | 0.88 (0.80-0.98) | 3 | 0.6 d |
| 3B | 2B2 | PGRN | 48 | 38 (34-43) | 15 (12-18) | 4 | 36 (28-47) | 0.85 (0.73-0.98) | 3 | 2.4 d |
| 3C | 33B12 | FABP4 | nd | 70 (52-97) | 1390 (883-2200) | 2 | 360 (317-406) | 0.83 (0.54-1.1) | 4 | 0.26 |
a apparent activity of mAb (expressed as a percent of its nominal concentration) as determined via Biacore’s CFCA or the KinExA’s fitted LCM converted into percent activity (where LCM of 1 = 100%). The 95% confidence interval of the KinExA fit is shown in parentheses.
b in undiluted serum
c KD ratio of serum antigen/recombinant antigen
d the difference in apparent KD values between purified recombinant antigen and serum antigen is pH-influenced
n = the number of independent titration curves incorporated in the global fitnd = not determined