Immunotherapy has the potential to be a powerful tool for cancer treatment. Yet, despite intensive research with both unmodified and conjugated monoclonal antibodies (mAbs), such reagents have yet to achieve their envisioned success. A true evaluation of the efficacy of cancer immunotherapy would be afforded by access to human antibodies against appropriate cell-surface markers that allow the specific targeting of tumor cells. In this way, a therapeutic antibody could be administered with uncompromised dosing protocols. We present a strategy wherein antibody phage-display technology, in conjunction with the synthesis of structurally defined carbohydrate """"""""panning reagents"""""""" analogous to tumor antigens, can be used to obtain human mAbs against tumor-associated antigens. First, human antibodies would allow the full exploitation of passive immunological treatments for various cancers, since the antibody composition is native to humans. Second, the glycosphingolipids (GSLs) and glycoproteins are currently the most well known distinguishing markers available for specifically targeting tumor cells. Using our expertise in antibody-phage technology we will construct novel single chain antibody (scFv) libraries from the blood of cancer patients as a source of human mAbs. With our experience in chemoenzymatic synthesis, we will prepare panning reagents based on the structures of tumor-associated GSLs and glycoproteins for direct in vitro selection. Selection techniques pioneered in our laboratory will provide a means to obtain human scFvs with high affinity and well-defined specificity against a designated panel of panning reagents. We will use advanced antibody engineering techniques to perform affinity maturation of the initially selected antibodies to refine tumor-antigen specificity within the specific cancer cell line. Finally, we will also engineer our scFvs to provide human monoclonal whole IgG, as well as scFv immunopharmacological reagents. Both constructs will be applicable to passive immunotherapeutic paradigms. Our approach would enable, for the first time, the complete assessment of the efficacy of immunotherapy for cancer treatment.
