Anti-histamine-succinyl-glycine binding site on bispecific monoclonal antibody

The anti-HSG binding site on a bispecific monoclonal antibody is not a naturally occurring molecular target but an engineered antigen-binding site (paratope) specific for the hapten histamine-succinyl-glycine (HSG). Bispecific antibodies containing this site have one arm that binds a tumor-associated antigen (such as carcinoembryonic antigen, CEA), and another that binds HSG. After the antibody localizes to the tumor, a radiolabeled HSG peptide is injected and binds specifically to the prelocalized antibody, enabling precise imaging or delivery of radiation to cancer cells. This system forms the basis for several pretargeted radioimmunotherapy and molecular imaging protocols in clinical research[4][1]. In summary, this entry describes an engineered binding site on a bispecific antibody—an important tool in certain targeted cancer therapies, but not a canonical drug target on its own.

Other names

Anti-HSG paratopeHSG binding site on bispecific antibodyAnti-hapten binding site

Enables pretargeting strategies—bispecific antibody is first administered and binds to a primary tumor antigen; afterwards, a small radiolabeled HSG-peptide is administered, which binds to the anti-HSG site, achieving targeted delivery of the radionuclide[4][1]