25-hydroxy Cholesterol

25-hydroxy Cholesterol (CAS No.: 2140-46-7) is an endogenous oxysterol belonging to the class of cholesterols and derivatives, generated from cholesterol by cholesterol-25-hydroxylase and prominently produced by macrophages in response to inflammatory stimuli such as Toll-like receptor activation. Functionally, it acts as a key regulator of cholesterol homeostasis and immune responses by binding to insulin-induced gene proteins, thereby inhibiting the transport and activation of sterol regulatory element-binding proteins and suppressing endogenous cholesterol biosynthesis. In immunological contexts, 25-hydroxy Cholesterol exhibits potent and selective inhibitory effects on B cell function, including suppression of IgA production and class switching induced by lipopolysaccharides and cytokines, with activity observed in the nanomolar range. Additionally, it has demonstrated antiviral properties, including the ability to inhibit viral replication and reduce viral protein expression in cell-based models, as well as lowering viral RNA levels in animal models under certain experimental conditions. These combined lipid-regulatory, immunomodulatory, and antiviral activities make 25-hydroxy Cholesterol a valuable tool for studying host–pathogen interactions, innate immunity, and sterol metabolism, and it is widely applied in cell-based assays and preclinical models, where experimental concentrations and dosing regimens are tailored to specific study designs and research objectives.