In contrast, the in vitro binding inhibition flow cytometry assay allows the ADAs to interact with the soluble mouse 14.G2a mAb (which shares the idiotype of the hu14.18-IL2 IC) in solution, and evaluates detection of GD2 binding in a cellular context, enabling the detection of ADAs that inhibit or interfere with the binding of a therapeutic drug to its specific target in its natural form on the cell surface, e.g., GD2 on tumor cells. Here, IL2 is linked to neoplasm.