| abstract |
There is provided inter alia a polypeptide comprising an immunoglobulin chain variable domain comprising three complementarity determining regions (CDR1-CDR3) and four framework regions, wherein: (a) at least one lysine residue in CDR1, CDR2 and/or CDR3 has been substituted with at least one histidine residue, and/or (b) at least one arginine residue in CDR1, CDR2 and/or CDR3 has been substituted with at least one histidine residue; wherein the polypeptide has increased intestinal stability relative to a corresponding polypeptide not having said histidine substitutions. |