Table 1. Characteristics of a panel of anti-HBsAg monoclonal antibodies.
Antibody | Subclass | Degree of disulfide sensitivitya | Epitope typeb | Dimer HBsAgc | Monomer HBsAgc | Binding strengthd | EC50 (ng/mL)e |
---|---|---|---|---|---|---|---|
Highly sensitive to DTT treatment (>10) | |||||||
22F10 | IgG1 | >440 | C | - | - | very strong | 0.18 |
A2C1 | IgG1 | >240 | C | - | - | very strong | 0.34 |
15D1 | IgG1 | >220 | C | - | - | very strong | 0.36 |
5F11 | IgG2a | >220 | C | + | +/− | very strong | 0.37 |
127D7 | IgG1 | >33.5 | L | + | + | strong | 2.4 |
20A2 | IgG2b | 10.1 | C | - | +/− | strong | 2.9 |
Sensitive (1.3~10) | |||||||
---|---|---|---|---|---|---|---|
SF | IgM | >9.02 | C | +/− | - | medium | 8.9 |
A10C2 | IgG1 | 6.74 | L | + | + | very strong | 0.59 |
SA1 | IgG2a | >3.63 | C | - | - | weak | 22.0 |
E2A9 | IgG2a | 3.22 | L | + | + | strong | 1.1 |
129G1 | IgG1 | 2.01 | L | + | + | very strong | 0.91 |
6C10 | IgM | 1.43 | L | + | + | strong | 1.4 |
Not sensitive (0.7~1.3) | |||||||
---|---|---|---|---|---|---|---|
13H10 | IgM | 1.21 | L | + | + | medium | 7.5 |
A13A2 | IgG2b | 0.97 | L | + | + | strong | 2.2 |
42B6 | IgG1 | 0.89 | L | + | + | very strong | 0.94 |
G12F5 | IgG1 | 0.77 | L | + | + | very strong | 0.75 |
75C12 | IgG1 | 0.72 | L | + | + | weak | 29.8 |
Preferring reduced HBsAg (<0.7) | |||||||
---|---|---|---|---|---|---|---|
E7D4 | IgG2a | 0.49 | L | + | + | medium | 4.2 |
E11E4 | IgG2a | 0.39 | L | + | + | strong | 1.2 |
83H12 | IgG1 | 0.23 | L | + | + | medium | 4.6 |
45E9E | IgG3 | 0.22 | L | + | + | weak | 56.8 |
E9B3 | IgG3 | 0.12 | L | + | + | weak | 34.4 |
The degree of sensitivity to DTT treatment for a given mAb was indicated by fold change in EC50 value in direct binding ELISA. aDegree of disulfide sensitivity was assessed in a direct binding ELISA on HBsAg-coated plates. Relative binding data were derived from (DDT-treated HBsAg EC50)/ (HBsAg in PBS EC50) based on curve fitting results. bEpitope type identified via Western Blotting,15 “C” means conformational and “L” means linear. cMonomer HBsAg and dimer HBsAg15 were used by SIA (strip immunoblot assay), SIA strips contained 2 individual bands: a SDS-treated HBsAg dimer (5 μg, obtained from SDS-treated HBsAg by electro-elution), a SDS-treated HBsAg monomer (5 μg, obtained from SDS-treated HBsAg by electro-elution). dBinding strength for a given mAb was assigned based on the EC50 value of direct binding ELISA data. These mAbs were classified into 4 different groups: very strong (EC50 < 1 ng/mL), strong (1 ng/mL < EC50 < 3 ng/mL), medium (3 ng/mL < EC50 < 10 ng/mL), weak (10 ng/mL < EC50). eEC50 values were derived from 4-parameter logistics fits of the direct binding ELISA data. Binding affinity as reflected EC50 values may not correlate to the neutralization activity for different mAbs. The neutralization activity is more dependent on the epitope recognized by a given mAb.