CD28 Costimulation Provided through a CD19-Specific Chimeric Antigen Receptor EnhancesIn vivoPersistence and Antitumor Efficacy of Adoptively Transferred T Cells

Abstract

Chimeric antigen receptors (CAR) combine an antigenbinding domain with a CD3-Z signaling motif to redirect Tcell specificity to clinically important targets. First-generation CAR, such as the CD19-specific CAR (designated CD19R), may fail to fully engage genetically modified T cells because activation is initiated by antigen-dependent signaling through chimeric CD3-Z, independent of costimulation through accessory molecules. We show that enforced expression of the fulllength costimulatory molecule CD28 in CD8 + CD19R + CD28À T cells can restore fully competent antigen-dependent T-cell activation upon binding CD19 + targets expressing CD80/CD86. Thus, to provide costimulation to T cells through a CD19-specific CAR, independent of binding to CD80/CD86, we developed a second-generation CAR (designated CD19RCD28), which includes a modified chimeric CD28 signaling domain fused to chimeric CD3-Z. CD19R + and CD19RCD28 + CD8 + T cells specifically lyse CD19 + tumor cells. However, the CD19RCD28 + CD8 + T cells proliferate in absence of exogenous recombinant human interleukin-2, produce interleukin-2, propagate, and up-regulate antiapoptotic Bcl-X L after stimulation by CD19 + tumor cells. For the first time, we show in vivo that adoptively transferred CD19RCD28 + T cells show an improved persistence and antitumor effect compared with CD19R + T cells. These data imply that modifications to the CAR can result in improved therapeutic potential of CD19-specific T cells expressing this second-generation CAR. (Cancer Res 2006; 66(22): 10995-1004)

Chimeric antigen receptor modified T cell therapy for B cell malignancies

“…2) [18]. Subsequent studies demonstrated that activation of T cells engineered to express first-generation CARs was incomplete and that T cells modified with second-or third-generation CARs that incorporated, respectively, one or more intracellular costimulatory signaling domains derived from CD28, 41BB, OX40, DAP10, ICOS, or CD27 possessed greater proliferative capacity, cytokine secretion, and anti-tumor activity than their first generation counterparts [27][28][29][30][31][32][33][34]. The importance of costimulation was confirmed in a clinical trial in which patients with B cell non-Hodgkin lymphoma were treated with T cells modified to express a CD19-specific CAR that incorporated either a CD28 costimulatory domain or no costimulation [35].…”

DNAX-activating protein 10 co-stimulation enhances the anti-tumor efficacy of chimeric antigen receptor T cells

“…6–8  The first-generation CAR utilized only CD3z to activate T cells without incorporating a co-stimulatory domain, the in vivo anti-tumor efficacy of these cells is poo. 9 Second-generation CAR-T cells, which generally utilize CD28 or 4-1BB as a co-stimulatory signal, have shown surprising efficacy in leukemia patient. 2,6,10 Nonetheless, the efficacy of CAR-T cells against solid tumors remains poor and uncertain, perhaps due to factors that suppress T cell responses in the tumor microenvironmen.…”

Anti-tumor activity and trafficking of self, tumor-specific T cells against tumors located in the brain

“…Pre-clinically, the Pmel-1 TCR transgenic murine tumor model recapitulates many features of the clinical experience and is particularly suitable, since the TCR transgenic T cells are specific for a self antigen, as opposed to a strong xenoantigen. Pmel-1 T cells bear a transgenic TCR that recognizes the gp100 [25][26][27][28][29][30][31][32][33] H-2D b -restricted epitope of the melanoma tumor antigen gp100, which is expressed by murine B16 melanomas [31] and GL261 gliomas [38]. Adoptive transfer of Pmel-1 CD8 + T cells alone into lymphodepleted C57BL/6 mice has no impact on the growth of established subcutaneous B16 tumors.…”

“…Adoptive transfer of Pmel-1 CD8 + T cells alone into lymphodepleted C57BL/6 mice has no impact on the growth of established subcutaneous B16 tumors. Regression of established B16 occurs only when the adoptive transfer is complemented by vaccination with recombinant viral vectors expressing human gp100 or syngeneic dendritic cells (DC) pulsed with the human gp100 [25][26][27][28][29][30][31][32][33] (hgp100 [25][26][27][28][29][30][31][32][33] ) peptide, followed by systemic administration of high doses of IL-2 or IL-15 as sources of helper cytokines [1,14,15,31,32,51].…”

“…PET and bioluminescent imaging have emerged recently as new strategies to longitudinally visualize the in vivo distribution and tumor targeting of immune cells transduced to express reporter genes. Our group and others have demonstrated the feasibility of both BLI and micro PET-based in vivo imaging approaches to monitor anti-tumor immunity [2,8,11,23,24,25,33,40,46,47,48]. In this study, we adapted BLI to allow us to test our hypothesis that T cells specific for endogenous melanoma antigens can localize into brain tumors and exert an antitumor effect.…”