Interaction of polysaccharides with interferon-gamma using an improved ELISA approach

Establishes an ELISA approach to study the interaction of polysaccharides with cytokine in vitro. Synthesizes and separates heparin–BSA complex, after identification of the complex via SDS-PAGE, the ELISA plate wells are coated with HBC, detecting the interaction of interferon-gamma (IFN-γ) with heparin–BSA complex. We have investigated recombinant human IFN-γ (rhIFN-γ) binds to heparin in a concentration-dependent manner. Free heparin and low molecular weight heparin (LMW heparin) competes for the binding of IFN-γ to heparin, the IC50 concentrations give 2.40 and 18.60 μg/ml, respectively. Other polysaccharides either with sulfate group or without sulfate group compete for the binding of IFN-γ to HBC with significant different ability. The results suggest that IFN-γ is a cytokine binding to some polysaccharides including heparin, chondroitin sulfate, fucoidan and carrageenans family with different affinity. ELISA is a simple, sensitive approach to detect the interaction of cytokine with polysaccharides.