PROBLEM TO BE SOLVED: To provide an antigen-binding molecule specific to a target tissue, an antigen-binding molecule whose antigen-binding activity changes according to the concentration of an unnatural compound, a library containing a plurality of different antigen-binding molecules, and a pharmaceutical composition containing the antigen-binding molecule. , A method for screening the antigen-binding molecule, a method for producing the same, and the like. SOLUTION: An antigen-binding molecule containing an antigen-binding domain or an antigen-binding domain whose binding activity to an antigen changes depending on the concentration of a low-molecular-weight compound is created, and a plurality of different antigen-binding domains or antigen-binding domains are created. It was found that the above-mentioned problems can be solved by creating a library containing the above-mentioned substances and using the library. By using the antigen-binding molecule of the present invention, various diseases caused by the target tissue can be treated specifically for the target tissue. [Selection diagram] None【課題】標的組織特異的な抗原結合分子、非天然化合物濃度に応じて抗原結合活性の変化する抗原結合分子、それぞれ異なる複数の該抗原結合分子を含むライブラリ、当該抗原結合分子を含む医薬組成物、当該抗原結合分子をスクリーニングする方法、およびそれを製造する方法等の提供。【解決手段】低分子化合物の濃度に依存して抗原に対する結合活性が変化する抗原結合ドメインまたは抗原結合ドメインを含む抗原結合分子を創作し、さらにはそれぞれ異なる複数の該抗原結合ドメインまたは抗原結合ドメインを含むライブラリを創作し、該ライブラリを用いることで、上記課題を解決できることを見出した。本願発明の抗原結合分子を用ることにより、標的組織に起因する各種疾患を標的組織特異的に治療することが可能となる。【選択図】なし
