Chimeric antigen receptor structure and manufacturing of clinical grade CAR engineered cells using different bioreactors

Increasing success of adaptive cell therapy (ACT), such as genetically engineered T cells to express chimeric antigen receptors (CARs) proven to be highly significant technological advancements and impressive clinical outcomes in selected haematological malignancies, with promising efficacy. The evolution of CAR designs beyond the conventional structures is necessary to address some of the limitations of conventional CAR therapy and to expand the use of CAR T cells to a wider range of malignancies. There are various obstacles with a wide range of engineering strategies in order to improve the safety, efficacy and applicability of this therapeutic modality. Here we describe details of modular CAR structure with all the necessary domains and what is known about proximal CAR signalling in T cells. Furthermore, the global need for adoptive cell therapy is expanding very rapidly, and there is an urgent increasing demand for fully automated manufacturing methods that can produce large scale clinical grade high quality CAR engineered immune cells. Despite the advances in automation for the production of clinical grade CAR engineered cells, the manufacturing process is costly, consistent and involves multiple steps, including selection, activation, transduction, and Ex-Vivo expansion. Among these complex manufacturing phases, the choice of culture system to generate a high number of functional cells needs to be evaluated and optimized. Here we list the most advance fully automated to semi-automated bioreactor platforms can be used for the production of clinical grade CAR engineered cells for clinical trials but are far from being standardized. New processing options are available and a systematic effort seeking automation, standardization and the increase of production scale, would certainly help to bring the costs down and ultimately democratise this personalized therapy. In this review, we describe in detail different CAR engineered T cell platforms available and can be used in future for clinical-grade CAR engineered ATMP production.