Both cytotoxic T cells and helper T cells are important in immune responses against pathogens and malignant cells.In hematological malignancies which express HLA class II molecules, immunotherapy may be directed to HLA class II restricted antigens. We investigated whether it is possible to engineer HLA class II restricted T cells with both antigenspecific cytolytic activity and the capacity to produce high amounts of cytokines. CD4 + and CD8 + peripheral-bloodderived T cells were retrovirally transduced with the HLA class II restricted minor histocompatibility antigen dead box RNA helicase Y (DBY)-specific TCR. The TCR-transduced CD4 + T cells exerted DBY-specific cytolytic activity, produced Th0, Th1, or Th2 cytokines, and proliferated upon DBY-specific stimulation. TCR-transduced CD8 + T cells exerted cytolytic activity which equaled the level of cytolytic activity of the TCR-transferred CD4 + T cells. Cotransfer of CD4 enhanced the cytolytic activity of the TCR-transduced CD8 + T cells, but introduction of CD4 was not sufficient to generate DBY-specific CD8 + T cells with the capacity to produce high amounts of cytokines. In this study, we demonstrated the feasibility to engineer T cells with antigen-specific cytolytic activity, as well as the ability to produce significant amounts of cytokines, by TCR transfer to CD4 + T cells. Gene Therapy (2005)
IntroductionPatients relapsing from leukemia after allogeneic stem cell transplantation can successfully be treated by donor lymphocyte infusions (DLI), due to the graft-versusleukemia (GVL) response of the donor-derived T cells. [1][2][3][4] However, DLI is also associated with graft-versus-hostdisease (GVHD). Several studies have illustrated that depletion of CD8 + T cells from the DLI may preserve the beneficial GVL reactivity without the induction of GVHD, indicating that the CD4 + T lymphocytes may play an essential role in the antileukemic reactivity. [5][6][7][8][9][10] The mechanism by which the CD4 + T cells contribute to the GVL response is, however, not known. CD4 + T cells have been suggested to elicit the antileukemic response via the induction of minor histocompatibility antigen (mHag)-specific CD8 + T cells. 5 In addition, mHag-specific CD4 + T-helper cells have been reported to mature dendritic cells and enhance the expansion of mHag-specific cytotoxic T lymphocytes in vitro. 11 Alternatively, we have demonstrated that CD4 + T cells are capable of exerting direct cytolytic activity against leukemic cells. [12][13][14] Cellular immunotherapeutic approaches based on the adoptive transfer of T lymphocytes may require large cell numbers. Large numbers of T cells with a defined antigen specificity can be acquired by retroviral transfer of the T-cell receptor to peripheral-blood-derived T lymphocytes. Until now, the application of retroviral transfer of TCRs has mainly been limited to the transfer of HLA class I restricted TCRs. [15][16][17][18][19][20] However, the specificity of HLA class II restricted T lymphocytes can also be transferred to other T c...