Chimeric Antigen Receptor T Cells in Tumor Immunology: Opportunities and Challenges

Adoptive transfer of antigen-specific T cells has been adapted by investigators for treatment of cancer. This technology is becoming popular in the aspects of cell in vitro preparation and T cell proliferation. In addition, it also does well in enhancing immunity effect and reducing cytotoxicity. A major advantage for this adoptive T-cell therapy (ACT) is its ability to efficiently endow patient’s T cells with reactivity for tumor antigens through stable or regulated introduction of genes that encode high affinity tumor-targeting T-cell receptors (TCRs) or synthetic chimeric antigen receptors (CARs). To overcome issues of immune tolerance which limit the endogenous adaptive immune response to tumor-associated antigens (TAAs), robust systems for genetic modification and characterization of T cells that express the chimeric antigen receptors (CARs) for redirecting their specificity have been produced. More and more cases have indicated that the CAR-T cells are excellent in cancer treatment. However, they still have many limitations in the treatment of solid malignancies. In addition, the toxicity of CARs T cells is also a serious problem in the CAR therapy as well. At present, the CAR therapy has been developed through four generations. This review thus focuses on the opportunities and challenges facing the CAR-T cells.