PDF file - 21K, BBIR-z T cells loaded with biotinylated molecules and then washed do not produce IFN�� in response to specific antigen stimulation. Following 45min incubation at 37oC with 1ug/ml of mesothelin specific biotinylated antybodies; P4 Biobody or K1 and control Bio-IgG1 antibody, BBIR-z T cells were washed with PBS and tested against plate-immobilized human mesothelin (105 cells/10ng mesothelin/well). After overnight incubation, culture supernatants were analyzed for human IFN�^ cytokine by ELISA. Concentration of IFN�� is expressed in pg/ml (means �� SEM; n = 3).
ARTICLE ABSTRACT
Adoptive immunotherapies composed of T cells engineered to express a chimeric antigen receptor (CAR) offer an attractive strategy for treatment of human cancer. However, CARs have a fixed antigen specificity such that only one tumor-associated antigen (TAA) can be targeted, limiting the efficacy that can be achieved because of heterogeneous TAA expression. For this reason, a more generalized and effective application of CAR therapy would benefit from the capability to produce large panels of CARs against many known TAAs. In this study, we show a novel strategy to extend the recognition specificity potential of a bioengineered lymphocyte population, allowing flexible approaches to redirect T cells against various TAAs. Our strategy employs a biotin-binding immune receptor (BBIR) composed of an extracellular-modified avidin linked to an intracellular T-cell signaling domain. BBIR T cells recognized and bound exclusively to cancer cells pretargeted with specific biotinylated molecules. The versatility afforded by BBIRs permitted sequential or simultaneous targeting of a combination of distinct antigens. Together, our findings show that a platform of universal T-cell specificity can significantly extend conventional CAR approaches, permitting the tailored generation of T cells of unlimited antigen specificity for improving the effectiveness of adoptive T-cell immunotherapies for cancer. Cancer Res; 72(7); 1844–52. ©2012 AACR.
