Polyclonal T-cell surface antigens

Polyclonal T-cell surface antigens comprise a broad spectrum of proteins expressed on the surface of T-lymphocytes and their precursors, thymocytes [3, 5]. This collective target includes essential signaling receptors (e.g., CD3, TCR), co-receptors (e.g., CD4, CD8, CD28), adhesion molecules (e.g., CD11a, CD18, CD44), and activation markers (e.g., CD25, HLA-DR) [1, 6]. These antigens are targeted by anti-thymocyte globulin (ATG), a polyclonal antibody therapy derived from rabbits or horses [2, 7]. The interaction between ATG and these surface antigens leads to rapid T-cell depletion via complement-mediated lysis and apoptosis, as well as the modulation of T-cell functions such as homing and cytotoxic activity [4, 8]. This multi-antigen targeting approach is clinically utilized to prevent and treat acute cellular rejection in solid organ transplantation and to manage bone marrow failure in aplastic anemia [3, 13]. Beyond T-cells, some ATG preparations also interact with antigens on B-cells, natural killer cells, and dendritic cells, further broadening the immunosuppressive effect [10, 11]. However, the extensive depletion of T-cells and the broad reactivity of the antibodies can lead to significant adverse effects, including cytokine release syndrome and a heightened risk of opportunistic infections [9, 15].

Other names

T-lymphocyte antigensThymocyte antigensLymphocyte-specific surface proteinsT-cell surface markers

Anti-thymocyte globulin (ATG) acts by binding to a wide array of T-cell surface antigens, leading to T-cell depletion through complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), and induction of apoptosis [3, 5]. It also modulates immune responses by downregulating surface receptors, interfering with T-cell homing and adhesion, and inducing regulatory T cells [1, 4].