Antibodies and antigen-binding fragments of antibodies that bind GCC are disclosed. The antibodies bind an extracellular domain of GCC and can be internalized. In some embodiments, the antibodies are humanized, chimeric or human. Nucleic acids and vectors encoding the antibodies or portions thereof, recombinant cells that contain the nucleic acids, and compositions comprising the antibodies or antigen-binding fragments are also disclosed. The invention also provides therapeutic and diagnostic methods utilizing the antibodies and antigen-binding fragments provided herein.本發明揭示結合GCC之抗體及抗體之抗原結合片段。該等抗體結合GCC之細胞外域且可內化。在一些實施例中，抗體為人類化、嵌合或人類抗體。亦揭示編碼該等抗體或其部分之核酸及載體、含有該等核酸之重組細胞及包含該等抗體或抗原結合片段之組合物。本發明亦提供利用本文所提供之抗體及抗原結合片段的治療法及診斷方法。
