Heparan sulfate (HS) is a linear polysaccharide found in all animal tissues. It occurs as a proteoglycan (HSPG) in which two or three HS chains are attached in close proximity to cell surface or extracellular matrix proteins. It is in this form that HS binds to a variety of protein ligands and regulates a wide variety of biological activities, including developmental processes, angiogenesis, blood coagulation, abolishing detachment activity by GrB (Granzyme B), and tumour metastasis. HS has been shown to serve as cellular receptor for a number of viruses including the respiratory syncytial virus (Hallak et al. 2000)