Abstract
Simple SummaryChimeric antigen receptors (CAR) can redirect the activity of NK cells to target T-cell malignancies. Our results identify that recognition of CD5 molecules in malignant T cells by the CAR leads to improved antitumor response compared to targeting CD3, due to strong downregulation of the CD3 antigen after CD3-CAR treatment. We have also identified that a specific CAR-NK framework has superior activity than a CAR-T framework on NK effector cells.NK effector cells expressing a CAR construct may be used to target T-lineage markers. In this work, we compared the activity of a NK-specific CAR-NK and a CAR-T framework when expressed on NK effector cells to target CD3 and CD5 in T-cell malignancies. Our results show that CD3-CAR-T is more active than CD5-CAR-T to eliminate malignant T cells in vitro, however, CD3-CAR-T were less efficient to eliminate tumor cells in vivo, while CD5-CAR-T had antitumor activity in a diffuse xenograft model. Lack of in vivo efficacy correlated with downregulation of CD3 levels in target T cells after coculture with CD3-CAR effector cells. The CAR-NK framework greatly improved the efficacy of CARs leading to increased degranulation, cytokine secretion and elimination of the tumor xenograft by CD5-CAR-NK effector cells. Finally, all CAR constructs were similarly effective to eliminate malignant T cells in vitro. Our results show that the NK-CAR framework improves the activity of CARs in NK cells and that CD5 would be a better target than CD3 for T-cell malignancies, as dynamic downregulation of target expression may affect in vivo efficacy.
Highlights
Recent years have shown remarkable success of chimeric antigen receptor (CAR)therapy for the treatment of advanced B-cell malignancies such as relapsed and refractory Bcell acute lymphoblastic leukemia (ALL) and B-cell non-Hodgkin lymphomas [1], bringing a possible cure to an otherwise untreatable condition
The scFv recognizing CD3 was derived from the sequence of mouse OKT3 antibody [6] and the scFv recognizing CD5 was derived from the sequence of the humanized
The CAR-T framework contains the hinge region, transmembrane and costimulatory domains of CD28, while the CAR-natural killer (NK) framework was derived from proteins expressed on NK cells and corresponded to a CD8a hinge region, a NKG2D transmembrane and a 2B4 costimulatory domain (Figure 1A) [14]
Summary
Therapy for the treatment of advanced B-cell malignancies such as relapsed and refractory Bcell acute lymphoblastic leukemia (ALL) and B-cell non-Hodgkin lymphomas [1], bringing a possible cure to an otherwise untreatable condition. The effectiveness of these treatments relies on targeting the B-cell lineage marker CD19, which is shared by healthy and malignant. Expression of the target molecule in CAR-T cells would result in a fratricide effect in which CAR-T cells eliminate CAR-T cells, leading to lack of efficacy. In this work we performed a comparative analysis of the activity of CARs recognizing two established targets for T-cell lymphoma, CD3 and CD5 using a CAR-T or a CAR-NK framework. The CAR-T framework is composed of a transmembrane and co-stimulatory domain derived from CD28 and CD3ζ, and the CAR-NK framework is composed of a transmembrane domain of NKG2D, a costimulatory domain of 2B4 and CD3ζ
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
