Multiple immune cell surface antigens targeted by antithymocyte globulin

ATG contains polyclonal antibodies generated by immunizing animals (typically rabbits or horses) with human lymphoid cells; the resulting antibodies recognize and bind to multiple cell surface antigens found on T cells, B cells, NK cells, monocytes, dendritic cells, and plasma cells. The principal mechanism is depletion of T lymphocytes via complement-mediated cytotoxicity, apoptosis, and antibody-dependent cellular cytotoxicity, although ATG also modulates other immune cell functions, inhibits cell activation, and disrupts leukocyte-endothelium interactions. The broad targeting results in profound immunosuppression, making ATG useful in preventing allograft rejection, treating graft-versus-host disease, and some autoimmune conditions, but also presenting risks such as acute infusion reactions, cytokine release syndrome, and increased susceptibility to infections. The use of the term “multiple immune cell surface antigens” as a drug target is non-specific and refers to a set of recognized molecules rather than a single defined therapeutic target, which may be relevant for mechanism summaries but is not suitable as a canonical molecular target form.

Other names

Thymocyte surface antigensLymphocyte cell surface markers (CD antigens)ATG targetsImmune cell antigens

Antibody-dependent cellular cytotoxicity (ADCC), Complement-dependent cytotoxicity, Induction of apoptosis (direct or via Fas-Fas ligand pathway), Modulation or downregulation of surface molecule expression, Opsonization and phagocytosis, Cytokine release and immunoregulation