Tumor-bound antibodies

Tumor-bound antibodies refer to the complex formed when therapeutic or endogenous antibodies, typically of the IgG class, bind to specific antigens expressed on the surface of malignant cells. These antibodies act as molecular markers that flag the tumor for recognition by the host's immune system, primarily through their Fc (fragment crystallizable) regions (Nimmerjahn & Ravetch, 2008). The Fc region is the functional domain that interacts with Fc gamma receptors (FcγRs) on effector cells like Natural Killer (NK) cells and macrophages to trigger Antibody-Dependent Cellular Cytotoxicity (ADCC) and phagocytosis (Wang et al., 2015). In modern drug development, tumor-bound antibodies are utilized as a modular target for 'universal' immunotherapies, such as Antibody-Coupled T-cell Receptor (ACTR) or CD16-CAR-T cells (Kudo et al., 2014). These therapies are engineered to bind the Fc portion of any IgG antibody, allowing a single drug product to be redirected against different tumor types by co-administering various antigen-specific antibodies like Rituximab or Trastuzumab (Unum Therapeutics, 2018). While this approach offers significant therapeutic flexibility, it faces challenges such as competition from high levels of endogenous circulating IgG and potential toxicity if the primary antibody binds to non-tumor tissues (D'Aloia et al., 2018).

Other names

IgG Fc regionOpsonized tumor cellsAntibody-antigen complexTumor-localized antibodies

Recruitment of effector cells to tumor sites by binding to the Fc region of antibodies previously bound to tumor-associated antigens.