Fei F, Rong L, Jiang N, Wayne AS, Xie J. Targeting HLA-DR loss in hematologic malignancies with an inhibitory chimeric antigen receptor.
Mol Ther 2022;
30:1215-1226. [PMID:
34801727 PMCID:
PMC8899520 DOI:
10.1016/j.ymthe.2021.11.013]
[Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/19/2021] [Accepted: 11/16/2021] [Indexed: 02/08/2023] Open
Abstract
Chimeric antigen receptor natural killer (CAR-NK) cells have remarkable cytotoxicity against hematologic malignancies; however, they may also attack normal cells sharing the target antigen. Since human leukocyte antigen DR (HLA-DR) is reportedly lost or downregulated in a substantial proportion of hematologic malignancies, presumably a mechanism to escape immune surveillance, we hypothesize that the anti-cancer specificity of CAR-NK cells can be enhanced by activating them against cancer antigens while inhibiting them against HLA-DR. Here, we report the development of an anti-HLA-DR inhibitory CAR (iCAR) that can effectively suppress NK cell activation against HLA-DR-expressing cells. We show that dual CAR-NK cells, which co-express the anti-CD19 or CD33 activating CAR and the anti-HLA-DR iCAR, can preferentially target HLA-DR-negative cells over HLA-DR-positive cells in vitro. We find that the HLA-DR-mediated inhibition is positively correlated with both iCAR and HLA-DR densities. We also find that HLA-DR-expressing surrounding cells do not affect the target selectivity of dual CAR-NK cells. Finally, we confirm that HLA-DR-positive cells are resistant to dual CAR-NK cell-mediated killing in a xenograft mouse model. Our approach holds great promise for enhancing CAR-NK and CAR-T cell specificity against malignancies with HLA-DR loss.
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