Binding of the two polypeptide chains of dengue virus-induced suppressor cytokine to its receptor isolated from macrophages

Abstract

Dengue type 2 virus (DV)-induced suppressor cytokine (SF) is composed of two polypeptide chains (α and β) and has a receptor on macrophages (Mφ), which has been purified. The present study was undertaken to study the binding of the two polypeptide chains of SF to Mφ and its purified receptor (SF-R) protein. It was observed that both α and β-chains of SF, purified by high performance liquid chromatography (HPLC), bound to Mφ cell, but only α-chain bound to SF-R protein. Only H-2A positive Mφ bound SF. Anti-H-2A^k mAb blocked the binding of SF to Mφ but had no effect on binding of SF to SF-R. Both anti-SF-antiserum and anti-SF-R-antiserum blocked the binding of SF to Mφ. The binding of the β-chain of SF to Mφ was blocked by anti-H-2A^k mAb while the anti-SF-R-antiserum blocked the binding of α-chain on Mφ. Thus, the α-chain of SF binds to SF-R and the β-chain binds to H-2A determinants on Mφ.