Antibody-drug conjugates (ADCs), which have become a new targeted therapy against cancer, consist of an antibody linked to a cytotoxic drug. The ADCs bind selectively to the target cancer cells via the monoclonal antibody portion. Internalization of the ADCs releases the drug to do its damage. This achieves target-specific killing of tumor cells while minizing systemic toxicity of the cytotoxic drug.

AlpVHHs offers a new generation of nano-secondary antibody-drug conjugates linked to MMAE, MMAF, DM1, or Duocarmycin, etc for antibody internalization detection.  Using Nano-secondary antibody-drug conjugates (nano-2°ADC) in a cell-based cytotoxic assay is a quick and economical alternative to pre-screening monoclonal antibodies as ADC candidates against tumor cells. Nano-2°ADCs are highly specific with minimally toxicity to cells in the absence of primary antibodies. No obvious change of the primary antibody activity in the presence of the unconjugated secondary antibody.