Immuno-suppressive effect of blocking the CD28 signaling pathway in T-cells by an active component of Echinacea found by a novel pharmaceutical screening method.

Guo-Chung Dong, Ping-Hsien Chuang, Michael D Forrest, Yi-Chen Lin, Hueih Min Chen

Index: J. Med. Chem. 49 , 1845-54, (2006)

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Abstract

AFTIR (after flowing through immobilized receptor) is a novel method for screening herbal extracts for pharmaceutical properties. Using AFTIR, we identified Cynarin in Echinacea purpurea by its selective binding to chip immobilized CD28, a receptor of T-cells, which is instrumental to immune functioning. The results of surface plasma resonance show that binding between immobilized CD28 and Cynarin is stronger than the binding between CD28 and CD80, a co-stimulated receptor of antigen presenting cells. Cynarin's function was verified by its ability to downregulate CD28-dependent interleukin-2 (IL-2) expression in a T-cell culture line. AFTIR offers promise as an efficient screening method for herbal medicines.