Peripheral blood T lymphocytes from HLA A2

Peripheral blood T lymphocytes from HLA A2.1donors were transduced with 3G6-CD28, 3G6-CD28TR, or NTP, and cocultured for 12 d as described in Materials and Methods with irradiated fibroblasts. most forms of immunotherapy have aimed to prime and expand tumor-reactive lymphocytes in vivo (4,5). Alternatively, adoptive antibody and cell therapies are based on the infusion of preformed immune effectors, whether antibodies (e.g., antibodies against the GD2antigen in neuroblastoma [6]) or lymphocytes (710). In principle, adoptive cell therapies are attractive in that they bypass many of the obstacles LY2140023 (LY404039) to the selective expansion of tumor-reactive lymphocytes in vivo by enabling their expansion in vitro. However, the generation of tumor-specific lymphocytes on one hand, and the sustained activity of cultured lymphocytes upon infusion in the recipient on the other, pose numerous problems (8). Adoptively transferred lymphocytes are indeed prone to cell death secondary to cytokine withdrawal, anergy secondary to inappropriate antigen presentation or downregulation of the TCR or other critical coreceptors. The engagement of the TCR is necessary to activate T cells, but not sufficient to achieve full activation. A second signal, or costimulation, is also required (1113). The interaction of the T cell surface receptor CD28 with the costimulatory ligands B7.1 and B7.2 expressed by professional APCs can induce a strong costimulatory signal resulting in the clonal expansion of activated T cells (1417). Thus, the costimulatory molecules expressed by the APC play a major role in determining LY2140023 (LY404039) whether survival, activation, or cell death will result from the interaction between the T lymphocyte and the APC (1214). CD28 signaling in T cells can prevent cell death secondary to either IL-2 withdrawal or TCR-mediated activation (1517). The absence of natural costimulatory molecules on tumor cells creates unfavorable conditions for the survival and activation of tumor-reactive T cells (13,1823). Different approaches can be taken to provide costimulation to tumor-specific T lymphocytes. One is to express B7 in tumor cells (5,24). However, the provision of costimulation in vivo by genetically modified tumor cells is confined to a small fraction of the total tumor burden. The success of this approach critically depends upon the ability to specifically target B7 expression to a sizable fraction of the tumor cells. It also depends on the sustained expression of CD28 by LY2140023 (LY404039) the activated T lymphocytes. On the LY2140023 (LY404039) other hand, the introduction in tumor-reactive T lymphocytes of a CD28-like receptor that is engaged by a tumor-associated antigen and expressed under the control of the retroviral LTR represents an alternative approach. The high efficiency gene transfer that is now achieved in human primary PBLs (25,26) makes this approach technically feasible. To enhance the survival and expansion of T lymphocytes reacting against tumor cells that lack costimulatory molecules but express a well-defined cell-surface antigen, we engineered a chimeric molecule that combines an antigen-specific single chain variable region fragment (scFv)1with the signal transduction domain of CD28. We reasoned that an scFv-CD28 fusion molecule AKT1 could specifically recognize the cell-surface epitope and mediate CD28 signaling functions, and thus mimic CD28/B7 interactions between T lymphocytes and tumor cells. The expression of an antigen-dependent CD28 receptor by adoptively transferred lymphocytes is expected to increase the probability that a T cell will survive and perhaps continue to proliferate when its TCR is engaged by target cells expressing the cell-surface antigen. The antigen-binding moiety we used was derived from the mAb 3G6 specific for the disialoganglioside GD2(27), an antigen abundantly expressed by neuroblastoma, small-cell lung carcinoma, melanoma, and some other tumors (6). Highly LY2140023 (LY404039) efficient retroviral-mediated gene transfer (25,26) enabled us to study the 3G6-CD28 fusion molecule in primary T cells rather than in cell lines or leukemic cells. We demonstrate that this receptor engages tumor-associated GD2antigen and mediates effective CD28 signaling in primary T lymphocytes. Polyclonal CD8+PBLs expressing 3G6-CD28 are selectively expanded when cultured with cells expressing MHC class I together with GD2. Thus, the transduced lymphocytes carry out a functional costimulatory response that enhances their survival and leads to their selective expansion in the absence of natural costimulatory molecules. == Materials and Methods == == Recombinant DNA Constructs. == The chimeric cDNA 3G6-CD28 comprises sequences encoding an scFv derived from the GD2-specific antibody 3G6 (27,28) and.