PROBLEM TO BE SOLVED: To provide a binding agent useful in the selective depletion of T cells in vivo.SOLUTION: The invention relates to ICOS-binding agents which once bound to ICOS expressed on the surface of cells, in particular ICOS-bearing activated T cells, result in the in vivo depletion of cells to which they are bound. Methods of treating T cell related diseases using the ICOS-binding agents, and pharmaceutical compositions comprising the ICOS-binding agents, a method of identifying an ICOS-binding agent, and monoclonal anti-ICOS antibodies capable of eliminating cells in vivo which express ICOS on their surface are also provided.【課題】ｉｎ ｖｉｖｏでＴ細胞の選択的枯渇に有用な結合物質の提供。【解決手段】細胞、特にＩＣＯＳを有する活性化Ｔ細胞の表面に発現したＩＣＯＳにいったん結合すると、ｉｎ ｖｉｖｏでそれが結合した細胞の枯渇をもたらすＩＣＯＳ結合物質。ＩＣＯＳ結合物質を用いたＴ細胞関連疾患の治療方法、及びＩＣＯＳ結合物質を含む医薬組成物、ＩＣＯＳ結合物質の同定方法、及びその表面にＩＣＯＳを発現する細胞をｉｎ ｖｉｖｏで除去可能な抗ＩＣＯＳモノクローナル抗体。【選択図】なし
