The present invention provides binding polypeptides (e.g., antibodies or fragments thereof) that specifically bind to a target antigen (e.g., a human antigen, e.g., human PDGFRβ) with high affinity. The invention also provides, libraries of binding polypeptides, pharmaceutical compositions, as well as nucleic acids encoding binding polypeptides, recombinant expression vectors and host cells for making such binding polypeptides. Methods of using binding polypeptide of the invention to diagnose and treat disease are also encompassed by the invention.本發明提供以高親和力特異性結合於目標抗原(例如人類抗原，例如人類PDGFRβ)之結合多肽(例如抗體或其片段)。本發明亦提供結合多肽之文庫、醫藥組合物，以及編碼結合多肽之核酸、重組表現載體及用於製造此等結合多肽之宿主細胞。本發明亦涵蓋使用本發明之結合多肽以診斷及治療疾病的方法。
