Provided is a novel composition. A composition for cytotoxic T cell depletion, the composition including an anti-LAG-3 antibody or a binding fragment thereof that has the properties described in (i) to (iii): (i) has in vitro ADCC activity； (ii) reduces the number of LAG-3-positive cells in vivo in low-fucose form； and (iii) binds to human activated T cells.本發明之課題係提供一種新穎組成物，其解決手段係一種細胞毒性T細胞耗竭用組成物，其包含具有下述(i)至(iii)記載之性質的抗LAG-3抗體或其結合片段：(i)具有活體外ADCC活性；(ii)在低海藻糖形態下，於活體內使LAG-3陽性細胞數減少；及(iii)與人類活化T細胞結合。
