AS 101 (CAS 106566-58-9) chemically known as ammonium trichloro(dioxoethylene-O O -)tellurate is a non-toxic immunomodulatory small molecule that acts primarily by inhibiting interleukin-10 (IL-10) signaling In cell-based studies AS 101 reduces IL-10 production and suppresses mesangial cell proliferation in a dose-dependent manner It has been shown to decrease tyrosine phosphorylation and nuclear translocation of STAT3 correlating with inhibition of IL-10 activity AS 101 stimulates IL-2 secretion and enhances immune cell function in both human and murine models In animal studies systemic administration confers bone marrow-sparing effects during chemotherapy mitigates alopecia enhances survival in sepsis models and modulates cytokine production These properties support its utility in investigating immune regulation and potential therapeutic interventions targeting cytokine-mediated pathologies