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Adoptive T Cell Therapy Using Educated T Cells Generated By the Sequential Stimulation With Dc/Tumor Fusion Cells and Anti-CD3/CD28

Year: 2009

Type: article

Abstract: Acute leukemia is susceptible to T cell mediated killing as evidenced by the graft versus disease effect following allogeneic transplantation. The development of adoptive immunotherapy to more selectively target tumor cells is an area of interest. Ligation of the CD3/CD28 complex results in expansion of T cells ex vivo with a phenotype that is dependent on the immunologic milieu during stimulation. We have developed a cancer vaccine in which autologous tumor cells are fused with dendritic cells (DCs). We postulated that stimulation with fusions followed by anti-CD3/CD28 would result in the expansion of activated T cells targeting tumor antigens. Tumor was obtained from peripheral blood or bone marrow of patients with AML. DCs were generated from adherent mononuclear cells cultured with rhIL-4, GM-CSF and TNFand fused with tumor cells by coculture in polyethylene glycol. T cells were stimulated by fusions prior to or following exposure to antiCD3/CD28 antibody coated plates. Stimulation by fusions followed by anti-CD3/CD28 resulted in the synergistic expansion of T cells, manifested by a greater stimulation index (SI) compared to stimulation by either pathway alone (SI 8.2 versus 3.3 with fusions alone). A rise in CD4+/CD25+ cells was noted following sequential stimulation with fusions and anti-CD3/CD28 (9.3% vs. 2.7% with fusions alone). An higher percentage of CD4+/CD25+ cells expressed IFNγ when exposed to fusions followed by anti-CD3/CD28 (7% compared to 2% with fusions alone). As compared to un-stimulated T cells, stimulation with fusions or anti-CD3/CD28 resulted in a 3.3 and 3.8 fold increase in CD8+ T cells expressing granzyme B, respectively. In contrast, sequential stimulation with fusions and anti-CD3/CD28 induced a 19-fold expansion of granzyme B+ cells consistent with enhanced cytolytic capacity. In spectratyping analysis, T cells undergoing sequential stimulation with fusions and anti-CD3CD28 demonstrate greater skewing of CDR3-size usage in the T cell receptor as compared to T cells stimulated by fusions or anti-CD3/CD28 alone. The pattern of gene expression in T cells stimulated sequentially by fusions and anti-CD3CD28 is being assessed. In conclusion, sequential stimulation of T cells by fusions and anti-CD3/CD28 results in the expansion of tumor reactive activated T cells. A clinical trial evaluating the use of T cells generated by sequential stimulation with DC/tumor fusions and anti-CD3CD28 for patients with acute leukemia is planned.

Source: Transplantation and Cellular Therapy

DOI: 10.1016/j.bbmt.2008.12.188