Monitoring of the formation of Anti-drug antibody (ADA) to biological therapeutic is an integral component of pre-clinical and clinical trials. Furthermore, in cases where ADA is detected, it is critical to determine if the antibody is capable of neutralizing the biological activity of TP. Two types of assays have been typically used for the measurement of NAb: (a) cell based biological assay, (b) non-cell based ligand binding assays.
The rationale behind the non-cell based assay is the notion that in vivo TP exerts its biological effects primarily through its interactions with TP-Receptors (TP-R) on target cells. A neutralizing ADA would bind to the structural components of the TP that is involved in the TP:TP-R interactions and consequently inhibit the binding of TP to its receptor. In this assay we utilized the inhibition (neutralization) of TP binding to a purified TP-Receptor by Anti-TP antibodies. Electrochemiluminescence (ECL) read out was used for monitoring these interactions. Decrease in ECL signal would be proportional to the amount of neutralizing Anti-TP antibody present in the sample.