[Study on T lymphocyte recognition of tumor antigens on autologous CML cells]

To investigate the existence of cytotoxic precursor cells in previously untreated or remissive chronic myelogenous leukemia(CML) patients,and identify their phenotypical and functional characteristics.

Bone marrow or peripheral blood mononuclear cells from CML patients were stimulated with autologous CML cells by using mixed lymphocyte tumor cell coculture.

A kind of cytotoxic T lymphocytes could be generated from bone marrow or peripheral blood of CML patients. These T cells showed differential cytotoxicities against autologous and allogeneic CML cells and no activity to autologous and allogeneic normal bone marrow cells. They also exhibited no inhibitive effect on CFU-GM yields. LAK cells had no effect on autologous CML cells, but showed intensive cytotoxic activity to allogeneic CML cells. The T lymphocytes obtained were CD3+ CD56+ non-MHC restricted or CD3+ CD56- MHC restricted. HLA-DR and CD25 were expressed in a significantly larger proportion of T lymphocytes stimulated with autologous CML cells than those not stimulated. The T lymphocytes showed low proliferative response to autologous CML cell stimulation and no or least response to allogeneic CML cells, they showed also no response to EB virus-transformed autologous B cells(obtained in remission) pulsed with peptides corresponding to the BCR-ABL joining region.

There is probably a common tumor antigen among CMLs, this leukemia-specific antigen can be recognized by T cells,and it shows no indication to be a p210 fusion sequence.