Immune response of post-transplant peripheral lymphocytes against the patient pre-B cell line, NAGL-1

We have established a pre-B acute lymphoblastic leukemia (ALL) cell Line, N AGL-1, from the bone marrow of a patient diagnosed with pre-B ALL. The pati ent has been disease-free for the 4 years since allogeneic bone marrow tran splantation from her HLA-genotypically identical sister. NAGL-1 showed a pr e-B cell phenotype (CD19+, CD10+, c mu+, s mu-) mostly identical. to freshl y isolated leukemic cells front the patient. This cell line strongly expres sed HLA class I and HLA-DR molecules, as well as the costimulatory molecule s CD54, CD40, and CD86. Cytotoxic T-lymphocyte (CTL) lines were generated b y stimulating the donor-derived peripheral blood mononuclear cells with eit her irradiated leukemic cells or NAGL-1. Both CTL lines showed specific lys is against NAGL-1 in Cr-51 release assays. Lytic activity was partially inh ibited by anti-CD8 and anti-HLA class I monoclonal antibodies. Treatment of NAGL-1 with TNF-alpha increased its susceptibility to the CTL line. One CD 8(+) T cell clone derived from the CTL line killed both the patient phytohe magglutinin (PHA) blasts and NAGL-1 but not the donor PHA blasts, suggestin g that the clone recognized the patient-specific minor antigen presented on both PHA blasts and NAGL-1. Utilization of leukemic cell lines could be a useful model for the development of CTL lines and clones for immunological study and potential immunotherapy. (C) 1999 The Japanese Society of Hematol ogy.