The present invention is related to a method for identifying a parvovirus mutated structural protein capable of specifically binding to a binder for an antigen, a parvovirus mutated structural protein which comprises at least one B-cell epitope heterologous to the parvovirus, a multimeric structure comprising the protein, a nucleic acid encoding the protein, a virus or cell comprising the protein, a method of preparing the protein, a medicament comprising the protein, nucleic acid or multimeric structure and its use.