Humanized CD30-Targeted Chimeric Antigen Receptor T Cells Exhibit Potent Preclinical Activity Against Hodgkin's Lymphoma Cells.

Jing Guo,Yongjie Zhu,Shuai He,Wei Yu,Dong Yang,Xudong Zhao

doi:10.3389/fcell.2021.775599

Abstract

CD30-directed chimeric antigen receptors (CARs) with single chain antibody fragment (scFv)-binding domains from murine HRS3 show strong cytotoxicity to Hodgkin’s Lymphoma cells and have been used in clinical trials. However, murine scFv in CAR might induce specific rejective immune responses in patients, which compromises the therapeutic effects. The use of human or humanized antibody fragments for CAR construction, rather than those derived from mouse antibodies, can reduce the immunogenicity of the CAR. Importantly, this strategy might simultaneously decrease the risk of cytokine-mediated toxicities and improve CAR T cell persistence. Murine HRS3 antibody has been successfully humanized by grafting the complementarity-determining regions (CDRs) from the mouse antibody framework onto human immunoglobulin consensus sequences, followed by an in vitro evolutionary strategy to select functional Fab fragments with the same affinity as murine sources. In this study, humanized scFvs were utilized to construct a CD30-directed CAR (hHRS3-CAR), and its effectiveness was compared with that of HRS3-CAR. The hHRS3-CAR-T cells specifically kill CD30-positive tumor cell lines in vitro and eliminate lymphoma xenografts in immunodeficient mice with comparable efficiency to HRS3-CAR. The hHRS-CAR-T could be used in clinical trials based on the previously reported advantages of humanized CARs, such as the reduction of immune rejection and better persistence of cells.

Highlights

Chimeric antigen receptors (CARs) are artificial proteins whose basic structure is composed of an antigen recognition ectodomain and activation endodomain linked by a spacer and transmembrane domain (Eshhar et al, 1993; Sadelain et al, 2013; Boyiadzis et al, 2016)
The CAR expressing anti-CD30(HRS3)-single chain antibody fragments (scFv) was used as the positive control and that expressing anti-cluster of differentiation 19 (CD19)-scFv was used as the negative control (CD19-CAR), as previously described (Sun et al, 2019)
Previous studies have demonstrated that the transfer of autologous human T-cells expressing foreign proteins, including CARs derived from murine scFvs, can elicit cellular and humoral immune responses that may compromise chimeric antigen receptor T-cells (CAR-T) effects (Lamers et al, 2006; Wang et al, 2020; Wagner et al, 2021)

Summary

Introduction

Chimeric antigen receptors (CARs) are artificial proteins whose basic structure is composed of an antigen recognition ectodomain and activation endodomain linked by a spacer and transmembrane domain (Eshhar et al, 1993; Sadelain et al, 2013; Boyiadzis et al, 2016) These are engineered receptors used to direct patient T cells to target tumor cells (Wang et al, 2019). In the normal physiological state, cell surface expression of CD30 is limited to activated T, B, and natural killer lymphocytes (Wasik et al, 2013) It is strongly expressed in malignant hematopoietic cells, including Hodgkin’s lymphoma (HL), anaplastic large cell lymphoma (ALCL), primary cutaneous ALCL, lymphomatoid papulosis, and certain cases of transformed mycosis fungoides (Schirrmann et al, 2014; van der Weyden et al, 2017). It was shown that anti-CD30 CAR-T cells can induce partial or complete remission in HL and ALCL (Wang et al, 2017; Ramos et al, 2020)

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