Title:
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Efficient elimination of primary B-ALL cells in vitro and in vivo using a novel 4-1BB-based CAR targeting a membrane-distal CD22 epitope
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Author:
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Velasco-Hernández, Talia; Zanetti, S. R.; Roca Ho, Heleia; Gutiérrez-Agüera, Francisco; Petazzi, Paolo; Sánchez-Martínez, D.; Molina, Oscar; Baroni, Matteo Libero; Fuster, José Luis; Ballerini, Paola; Bueno, Clara; Fernández-Fuentes, Narcís; Engel, P.; Menéndez Bujan, Pablo; Universitat Autònoma de Barcelona
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Abstract:
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Altres ajuts: Funding This work was supported by the Obra Social La Caixa (LCF/PR/HR19/52160011), the Spanish Cancer Association and Leo Messi Foundation to PM. |
Abstract:
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Background There are few therapeutic options available for patients with B-cell acute lymphoblastic leukemia (B-ALL) relapsing as CD19 - either after chemotherapy or CD19-targeted immunotherapies. CD22-chimeric antigen receptor (CAR) T cells represent an attractive addition to CD19-CAR T cell therapy because they will target both CD22 + CD19 - B-ALL relapses and CD19 - preleukemic cells. However, the immune escape mechanisms from CD22-CAR T cells, and the potential contribution of the epitope binding of the anti-CD22 single-chain variable fragment (scFv) remain understudied. Methods Here, we have developed and comprehensively characterized a novel CD22-CAR (clone hCD22.7) targeting a membrane-distal CD22 epitope and tested its cytotoxic effects against B-ALL cells both in in vitro and in vivo assays. Results Conformational epitope mapping, cross-blocking, and molecular docking assays revealed that the hCD22.7 scFv is a high-affinity binding antibody which specifically binds to the ESTKDGKVP sequence, located in the Ig-like V-type domain, the most distal domain of CD22. We observed efficient killing of B-ALL cells in vitro, although the kinetics were dependent on the level of CD22 expression. Importantly, we show an efficient in vivo control of patients with B-ALL derived xenografts with diverse aggressiveness, coupled to long-term hCD22.7-CAR T cell persistence. Remaining leukemic cells at sacrifice maintained full expression of CD22, ruling out CAR pressure-mediated antigen loss. Finally, the immunogenicity capacity of this hCD22.7-scFv was very similar to that of other CD22 scFv previously used in adoptive T cell therapy. Conclusions We report a novel, high-affinity hCD22.7 scFv which targets a membrane-distal epitope of CD22. 4-1BB-based hCD22.7-CAR T cells efficiently eliminate clinically relevant B- CD22 high and CD22 low ALL primary samples in vitro and in vivo. Our study supports the clinical translation of this hCD22.7-CAR as either single or tandem CD22-CD19-CAR for both naive and anti-CD19-resistant patients with B-ALL. |
Subject(s):
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-T-lymphocytes -Cell engineering -Hematologic neoplasms -Immunotherapy -Receptors -Chimeric antigen |
Rights:
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open access
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https://creativecommons.org/licenses/by-nc/4.0/ |
Document type:
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Article |
Published by:
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Uri:
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https://ddd.uab.cat/record/236713
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