Understanding The Effect Of Discreet PEG Linkers On ADC Structure And Binding

For an antibody-drug conjugate, the choice of the linker can have a dramatic effect on both physical structure and biological activity. The increased hydrophilicity provided by a PEG linker can influence the potency, toxicity and pharmacokinetics of the ADC. To investigate the chemical challenges that can be overcome by the right choice of the linker, we have explored the influence of a variety of PEG linkers on the structure of a model cysteine-bioconjugate. Specific sites of conjugation were identified by peptide mapping and changes in conformation were investigated by hydrogen/deuterium exchange mass spectrometry. The resulting impact on Fc receptor binding by surface plasmon resonance was also determined. These results illustrate the importance of an appropriate linker and the need for thorough product characterization in order to understand the structure-function relationships of an ADC.