Combining SiRPα decoy–coengineered T cells and antibodies augments macrophage-mediated phagocytosis of tumor cells
Evangelos Stefanidis, … , George Coukos, Melita Irving
Evangelos Stefanidis, … , George Coukos, Melita Irving
Published June 3, 2024
Citation Information: J Clin Invest. 2024;134(11):e161660. https://doi.org/10.1172/JCI161660.
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Combining SiRPα decoy–coengineered T cells and antibodies augments macrophage-mediated phagocytosis of tumor cells

Abstract

The adoptive transfer of T cell receptor–engineered (TCR-engineered) T cells (ACT) targeting the HLA-A2–restricted cancer-testis epitope NY-ESO-1157–165 (A2/NY) has yielded favorable clinical responses against several cancers. Two approaches to improve ACT are TCR affinity optimization and T cell coengineering to express immunomodulatory molecules that can exploit endogenous immunity. By computational design we previously developed a panel of binding-enhanced A2/NY-TCRs including A97L, which augmented the in vitro function of gene-modified T cells as compared with WT. Here, we demonstrated higher persistence and improved tumor control by A97L–T cells. In order to harness macrophages in tumors, we further coengineered A97L–T cells to secrete a high-affinity signal regulatory protein α (SiRPα) decoy (CV1) that blocks CD47. While CV1-Fc–coengineered A97L–T cells mediated significantly better control of tumor outgrowth and survival in Winn assays, in subcutaneous xenograft models the T cells, coated by CV1-Fc, were depleted. Importantly, there was no phagocytosis of CV1 monomer–coengineered T cells by human macrophages. Moreover, avelumab and cetuximab enhanced macrophage-mediated phagocytosis of tumor cells in vitro in the presence of CV1 and improved tumor control upon coadministration with A97L–T cells. Taken together, our study indicates important clinical promise for harnessing macrophages by combining CV1-coengineered TCR–T cells with targeted antibodies to direct phagocytosis against tumor cells.

Authors

Evangelos Stefanidis, Aikaterini Semilietof, Julien Pujol, Bili Seijo, Kirsten Scholten, Vincent Zoete, Olivier Michielin, Raphael Sandaltzopoulos, George Coukos, Melita Irving

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Figure 1

T cells expressing affinity-enhanced A2/NY-TCR A97L exhibit superior effector function in vitro compared with WT.

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T cells expressing affinity-enhanced A2/NY-TCR A97L exhibit superior eff...
(A) TCR variant A97L binding to A2/NY-ESO-1157–165 (Protein Data Bank ID 2BNR). A97L replacement in CDR3β (in ball and stick representation, colored in pink) enhances direct peptide contact via non-polar interactions with Thr7 (ball and stick representation, in gray, below TCRβ chain) as well as with MHC-Ala150 and -Lys146 (ball and stick representation, surface in orange). (B) Schematic of lentiviral constructs encoding TCRs. (C) Strategy for T cell activation, transduction, and expansion. (D) Transduction efficiency of CD8+ T cells with TCRs evaluated by tetramer staining (data are representative of 5 donors). (E) Top: Frequency of effector and memory phenotypes of rested CD8+ and CD4+ T cells transduced to express the different TCRs (n = 3). Bottom: Representative flow cytometric analysis of anti-CCR7 and anti-CD45RA Ab–stained T cells (TE, effector; TEM, effector memory; TCM, central memory; TN/SCM, naive/stem cell–like memory). (F) Expression (frequency) of activation markers and checkpoint receptors on CD8+ TCR-engineered T cells 24 hours after stimulation with A375 tumor cells (n = 5). HD, healthy donor. (G) IFN-γ secretion levels by TCR-modified T cells 24 hours after stimulation with NA8 and A375 tumor cells at effector/target ratio (E/T) = 1:1 (n = 3). (H) Frequency of annexin V+ DAPI+ cells, corrected to tumor alone, in 24-hour cocultures of NA8 and A375 tumor cells with TCR-modified T cells at E/T = 1:1 (n = 4). (I) Evaluation of mKate2+ NA8 and A375 tumor cell growth control over time by TCR–T cells at E/T = 1:1 using live-cell IncuCyte imaging (data are representative of 4 donors). Statistical analysis was done by 1-way ANOVA (E, G, and H) with correction for multiple comparisons by post hoc Tukey’s test (E, G, and H). *P < 0.05; ****P< 0.0001.