Abstract
Bispecific antibodies play an important role in immunotherapy. They have received intense interest from pharmaceutical enterprises. The first antibody drug, OKT3 (muromonab-CD3), showed great performance in clinical treatment. We have successfully developed a single-chain variable fragment (ScFv) combination of anti-CD3 ScFv and anti-CD138 ScFv with the hIgG1 Fc (hIgFc) sequence. The novel bispecific T-cell engager (BiTE) with an additional hIgFc (BiTE-hIgFc, STL001) can target T cells, natural killer cells, and multiple myeloma cells (RPMI-8226 or U266). In addition, BiTE-hIgFc (STL001) has nanomolar-level affinity to recombinant human CD138 protein and shows more potent antitumor activity against RPMI-8226 cells than that of separate aCD3-ScFv-hIgFc and aCD138-ScFv-hIgFc, or the isotype mAb in vitro or in vivo.