Dinactin is a hydrophobic cyclic ester originally produced by Streptomyces aureus. It acts as an antibiotic and cation ionophore, with high selectivity for ammonium and potassium ions. Dinactin has been reported to inhibit T-cell proliferation induced by IL-2 (interleukin-2). Additionally, this compound has been shown to inhibit cytokine production with IC50 values of 10 ng/ml. Mechanistic studies suggest that dinactin inhibits cytokine production through a post-transcriptional mechanism.