Cancer therapy with trifunctional antibodies: linking innate and adaptive immunity.

Trifunctional antibodies (trAbs) are promising novel anticancer biologics with a particular mode of action capable of linking innate with adaptive immunity. Based on their unique structure, trifunctional IgG-like heterodimeric antibodies, consisting of nonhuman mouse and rat immunoglobulin halves are able to redirect T lymphocytes, as well as accessory cells, to the tumor site. This recruitment of immune cells is accompanied by cellular activation events elicited by anti-CD3, as well as Fcγ-receptor engagement of trAbs supported by a proinflammatory Th1-biased cytokine milieu. All necessary immunological factors required for long-term vaccination-like effects are stimulated along trAb-mediated therapeutic interventions. Thus, the concerted interplay of antibody-dependent cellular cytotoxicity plus the polyclonal T-cell cytotoxicity and Fcγ-receptor-driven induction of long-lasting immune responses after the initial tumor cell elimination represent the major hallmarks of trAb-mediated treatment of malignant diseases.