The present invention pertains to: a polypeptide that includes an antigen-binding domain and a conveying section having an inhibitory domain for inhibiting the antigen-binding activity of the antigen-binding domain, and that has a half-life longer than that of the antigen-binding domain when existing alone； a production method and screening method for the polypeptide； a pharmaceutical composition containing the polypeptide； a production method and screening method for a single-domain antibody the antigen-binding activity of which is inhibited by being associated with a specific VL/VH/VHH； and a library of fused polypeptides including a single-domain antibody the antigen-binding activity of which is inhibited by being associated with a specific VL/VH/VHH.本發明係關於包含抗原結合域以及具有抑制抗原結合域之抗原結合活性之抑制域之運送部分，且比起單獨存在之抗原結合域有較長半衰期的多胜肽、該多胜肽之製造方法與篩選方法、含有該多胜肽之醫藥組合物、藉由與特定之VL/VH/VHH締合而抗原結合活性受抑制之單域抗體之製造方法及篩選方法、以及含有藉由與特定之VL/VH/VHH締合而抗原結合活性受抑制之單域抗體之融合多胜肽之資料庫。
