Question 1

How should binding affinity be measured and reported?

Accepted Answer

Surface-based kinetic methods resolve association and dissociation rates separately, which matters because a slow off-rate often drives potency more than the equilibrium value. Immobilise the antibody rather than the antigen where possible to avoid avidity effects, and confirm key values in solution. State orientation, buffer and analyte concentrations used.

Question 2

What does humanisation involve in practice?

Accepted Answer

Binding loops are grafted onto a human framework chosen for sequence similarity, which usually reduces affinity because framework residues support loop conformation. Restoring a small number of those positions recovers binding while keeping most of the sequence human. Measure affinity after every change rather than only at the end.

Question 3

Which developability properties should be screened early?

Accepted Answer

Thermal unfolding temperature, aggregation on concentration and after stress, viscosity at formulation-relevant concentration, charge heterogeneity, and sequence positions prone to oxidation, deamidation or unwanted glycosylation. Screening these alongside affinity avoids advancing a strong binder that cannot be formulated or manufactured.

Question 4

How is affinity improved beyond the starting clone?

Accepted Answer

Focused libraries diversifying binding loop positions, screened by display with increasing stringency, remain the standard route. Structure-guided substitution and learned sequence models propose smaller variant sets for direct testing. Combining individually beneficial substitutions frequently disappoints, so build and measure the combinations rather than assuming additivity.

Question 5

When does a smaller format serve better than a full antibody?

Accepted Answer

Smaller fragments and single-domain binders penetrate tissue better and reach recessed epitopes, at the cost of rapid clearance unless half-life extension is added. Bispecific designs engage two targets or recruit effector cells. Each format changes stability, production behaviour and pharmacokinetics, so the choice should follow the mechanism required.

Question 6

How is the constant region tuned?

Accepted Answer

Substitutions in the constant region adjust binding to receptors that mediate effector functions and to the receptor governing recycling and half-life. Glycan composition also strongly influences effector activity. Where effector function is undesirable, silencing substitutions are used, and any such variant needs functional confirmation rather than reliance on published behaviour.

Question 7

What evidence supports reduced immunogenicity?

Accepted Answer

Sequence-based prediction of peptide presentation gives an initial assessment, and in vitro assays using human cells measure T cell responses to the candidate. Neither predicts clinical outcomes reliably, so report them as risk indicators. Removing predicted epitopes should always be paired with confirmation that binding and stability survived the changes.

Biotechnology

Biotechnology

Research Frontiers in Antibody Engineering and Design