抄録
Although CD56+ T cells comprise less than 5% of human peripheral blood mononuclear cells (PBMCs), we observed that the percentage of CD56+ T cells was increased in activated T-cell populations used for adoptive immunotherapy. We hypothesized that this cell subpopulation might be an important cytotoxic effector in immunotherapy. PBMCs were obtained from both cancer patients and healthy donors. CD8+ single-positive T cells were separated with magnetic beads, and stimulated with immobilized anti-CD3 monoclonal antibody and IL-2. FACS analysis showed that the CD56 antigen was expressed more strongly on CD8 cells than on CD4 cells. The CD8+ CD56+ T cells have a tendency for more cytotoxic effects than the CD8+ CD56- T cells. SEM analysis showed that the CD56+ T cells adhered to one another, to form a cluster. Thus, T cell self-adhesion was increased by the expression of the adhesion molecule CD56. The cytotoxic CD8+ CD56+ T cells derived from CD8+ T cells in the peripheral blood are activated T cells that are distinct from natural killer T (NKT) cells.
