The present invention relates to modified proteins and peptides that have reduced ability to bind to pre-existing antibodies. Such modified protein/peptide molecules can comprise C-terminal additions, extensions or tags and/or certain amino acid substitutions. Such modified molecules (e.g. fusions and conjugates) comprise proteins, peptides, antigen binding molecules, antibodies or antibody fragments such as single variable domains e.g. human immunoglobulin (antibody) single variable domains, and also single variable domains derived from non-human sources such as a llama or camel, e.g. a VHH including a nanobodyTM (described in e.g. WO 94/04678 and WO 95/04079 inter alia). The invention further relates to uses, formulations, compositions comprising such modified C terminally extended and/or amino acid substituted molecules and also to methods of production and expression of these molecules.本發明係關於經修飾之蛋白質及肽，其結合預先存在之抗體之能力有所降低。此等經修飾之蛋白質/肽分子可包含C末端添加、延伸或標籤及/或某些胺基酸取代。此等經修飾之分子(例如融合物及偶聯物)包含蛋白質、肽、抗原結合分子、抗體或抗體片段，例如單一可變結構域，例如人類免疫球蛋白(抗體)單一可變結構域亦及源自非人類來源(例如駱馬或駱駝)之單一可變結構域，例如VHH，包括nanobodyTM(尤其闡述於例如WO 94/04678及WO 95/04079中)。本發明進一步係關於此等經修飾之C末端延伸及/或胺基酸取代分子之用途、包含該等分子之調配物、組合物，且亦係關於產生及表現該等分子之方法。
