Rapid selection of antigen-specific T lymphocytes by retroviral transduction

Infusions of donor peripheral blood T cells can induce durable remissions o f Epstein-Barr virus (EBV) lymphomas complicating marrow grafts, but they c ontain alloreactive T cells capable of inducing graft-versus-host disease. EBV-specific T-cell lines or clones avoid this problem but require 30 to 40 days of culture to establish. To accelerate the generation of EBV-specific T cells, we tested whether retroviral vectors, which only integrate in div iding cells, could be used to transduce and select antigen-reactive T cells early after sensitization to autologous EBV-transformed 8 cells. T cells w ere transduced with a dicistronic retroviral vector, NIT, which encodes low -affinity nerve growth factor receptor as an immuno-selectable marker and h erpes simplex virus thymidine kinase as a suicide gene, at different time p oints after sensitization. EBV-specific cytotoxic T lymphocyte precursor (C TLp) frequencies in purified NIT+ T-cell fractions transduced on day 8 of c ulture were comparable to those of EBV-specific T cell lines cultured for 3 0 days or more. Alloreactive CTLp frequencies were markedly reduced in the NIT+ fraction relative to the untransduced T-cell population. NIT+ fraction s transduced on day 8 possessed more CD4(+) T cells than the cell lines at day 30 and exhibited the same selective pattern of reactivity against immun odominant antigens presented by specific HLA alleles. In contrast, T cells transduced with NIT 5 days after stimulation with mitogen and interleukin-2 were relatively depleted of T cells specific for autologous EBV-transforme d cells. Thus, retroviral vectors may be used for rapid selection of viral antigen-reactive T cells depleted of alloreactive T cells. (Blood. 2000;96: 109-117) (C) 2000 by The American Society of Hematology.