An investigation into the heparin-binding properties of a synthetic peptide deduced from the antigenic domain 2 of human cytomegalovirus glycoprotein B.

An investigation was performed into the heparin-binding properties of a synthetic peptide deduced from the sequence of human cytomegalovirus glycoprotein B. The peptide, T7-13:3, amino acids 69-78, which was previously shown to contain a neutralization epitope was able to bind heparin coated onto microtitre plates as well as immobilized on agarose beads. Conversely, labelled heparin could be used to specifically detect the immobilized peptide. The peptide bound to human cells in a manner which suggested an interaction with extracellular matrix, and binding of the peptide to human fibroblasts could be inhibited both by adding soluble heparin and by enzymatic pretreatment of the cells with heparinase. The sequence of T7-13:3 shows similarity to several proteins with known or supposed ability to bind heparin, e.g. basic fibroblast growth factor, the heparin-binding capacity of which could also be inhibited by T7-13:3. The peptide was also found to bind DNA, probably due to the similarities between DNA and heparin in terms of structure and charge. Because heparin is a chemical homologue of heparan sulfate, the results strongly indicate that the sequence represented by T7-13:3 is involved in the binding of virus to cell surface heparan sulfate. The described region of gB may have the potential to contribute to a subunit vaccine although possible hazards, such as the induction of auto-antibodies to heparin, and thus also to DNA, need to be considered.