The present invention relates to a method of selecting a protein variant having modified immunogenicity as compared to the parent protein comprising the steps obtaining antibody binding peptide sequences, using the sequences to localise epitope sequences on the 3-dimensional structure of parent protein, defining an epitope area including amino acids situated within 5 Å from the epitope amino acids constituting the epitope sequence, changing one or more of the amino acids defining the epitope area of the parent protein by genetical engineering mutations of a DNA sequence encoding the parent protein, introducing the mutated DNA sequence into a suitable host, culturing said host and expressing the protein variant, and evaluating the immunogenicity of the protein variant using the parent protein as reference. The invention further relates to the protein variant and use thereof, as well as to a method for producing said protein variant.