Method for purifying viral vectors have proteins that bind to sialic acid

A method for isolating a target purification comprising a protein that binds specifically to sialic acid, said method comprising the step of: letting the aim of purification contact a molecule comprising sialic acid is linked to a solid support, for the purpose of purification which has a binding site for sialic acid binds selectively by the molecule, wherein the target purification comprises a protein of the selected capsid group consisting of a protein AAV capsid serotype 4, a protein of AAV capsid serotype 5 and a capsid comprising a fragment of a capsid or AAV4 AAV5 containing the binding site for sialic acid.