The present invention provides antigen-binding molecules containing (i) an antigen-binding domain whose antigen-binding activity varies depending on ion concentration conditions, (ii) an Fc³-binding domain having Fc³ RIIb-selective binding activity, and (iii) an FcRn-binding domain having FcRn-binding activity under an acidic pH range condition, and methods of decreasing plasma antigen concentration as compared to before administering the molecule, which include the step of administering the molecule.本發明提供一種抗原結合分子，其係含有(i)對抗原之結合活性依離子濃度之條件變化之抗原結合分域、(ii)對FcγRIIb有選擇性結合活性之FcγR結合分域、及(iii)於pH酸性域之條件下對FcRn具有結合活性之FcRn結合分域；並提供一種該抗原之血漿中濃度比起投予該分子前降低之方法，包含投予該分子的步驟。
