Targeting of G(D2)-positive tumor cells by human T lymphocytes engineered to express chimeric T-cell receptor genes

Genetic engineering of human T lymphocytes to express tumor antigen-specifi c chimeric immune receptors is an attractive means for providing large numb ers of effector cells for adoptive immunotherapy while bypassing major mech anisms of tumor escape from immune recognition. We have applied this strate gy to the targeting of a G(D2)-positive tumor, neuroblastoma, which is the commonest extracranial solid tumor of childhood. Chimeric immune receptors were generated by joining an extracellular antigen-binding domain derived f rom either of the 2 ganglioside G(D2)-specific antibodies sc7A4 and sc14.G2 a to a cytoplasmic signaling domain. The variable domains of hybridoma anti body 14.G2a were cloned and selected using a phage display approach. Upon c oincubation with G(D2)-expressing tumor cell targets, human T lymphocytes t ransduced with recombinant retroviruses encoding chimeric receptors based o n sc14.G2a, but not sc7A4, secreted significant levels of cytokines in a pa ttern comparable to the cytokine response obtained by engagement of the CD3 receptor. T cells transduced with the sc14.G2a-based chimeric T-cell recep tors also displayed specific lysis of G(D2)-positive neuroblastoma cells, w hich was blocked in the presence of monoclonal antibody 14.G2a. In the abse nce of nonspecific stimulation of transduced cells, their functionality dec lined over time and antigenic stimulation of the chimeric receptor alone di d not induce commitment to proliferation. These results support the feasibi lity of redirecting human T lymphocytes to a tumor-associated ganglioside e pitope but emphasize that successful chimeric receptor-mediated adoptive im munotherapy will require additional strategies that overcome functional ina ctivation of gene-modified primary T lymphocytes. (C) 2001 Wiley-Liss, Inc.