CD3X anti-nitrophenyl bispecific diabodies: universal immunotherapeutic tools for retargeting T cells to tumors

We developed a universal recombinant bispecific molecule (BiMol) that is capable of redirecting cytotoxic T cells to tumor cells via tagged anti-tumor ligands such as antibody fragments or cytokines. A recombinant bispecific diabody with binding specificities for the CD3 molecule on T cells as well as for the hapten nitrophenyl (NIP) was produced. This bispecific molecule is capable of redirecting cytotoxic T cells to kill a series of malignant cells, including B cell lymphoma, Hodgkin's lymphoma, and colon carcinoma via NIP-conjugated ligands to tumor-associated antigens. Cytotoxic activity of the diabody was found to be comparable to tetradoma-derived bispecific antibodies with similar specificities. Our findings demonstrate that universal CD3xanti-NIP diabodies could be used for T cell based cellular immunotherapy in a variety of human malignancies. Additionally, these bispecific molecules allow fast and economic testing of tumor-associated antigens on malignant cells for their potential use as immunotherapeutic target structures if corresponding hapten-conjugated antibodies or ligands are available.