The present invention has objects to provide a novel human T-cell population having both cytotoxic and immunosuppressive activities, and to a method for preparing the same. The above objects are attained by providing a human T-cell population which is obtainable by coculturing mononuclear cells, collected from human blood, with stroma cells and which has the following features: (1) being positive for CD3, CD25, CD28 and T-cell antigen receptor ±²； (2) essentially consisting of three groups of a CD4 positive and CD8 positive (CD4 + CD8 + ) T-cell group, a CD4 positive and CD8 dimly positive (CD4 + CD8 dim ) T-cell group, and a CD4 negative and CD8 positive (CD4 - CD8 + ) T-cell group； (3) exerting a cytotoxic activity against the cocultured stroma cells； and (4) exerting an immunosuppressive activity against activated T cells.本發明係提供一種具有細胞毒性及免疫抑制性2者兼具之新穎之人類T細胞群，並以提供其取得方法為課題，其可藉將由人血採取之單核球細胞與基質細胞一起培養而獲得，且具有下述之特徵：(1)CD3、CD25、CD28及T細胞抗原受體α β為陽性、(2)本質上由CD4陽性CD8陽性T細胞、CD4陽性CD8弱陽性T細胞及CD4陰性CD8陽性T細胞之三群所成、(3)相對於共同培養之基質細胞，可發揮造成細胞毒性，以及(4)對於活化之T細胞，發揮免疫抑制之活性。
