Costimulation of γδTCR and TLR7/8 promotes Vδ2 T-cell antitumor activity by modulating mTOR pathway and APC function.

Abstract

BACKGROUND:

Gamma delta (γδ) T cells are attractive effector cells for cancer immunotherapy. Vδ2 T cells expanded by zoledronic acid (ZOL) are the most commonly used γδ T cells for adoptive cell therapy. However, adoptive transfer of the expanded Vδ2 T cells has limited clinical efficacy.

METHODS:

We developed a costimulation method for expansion of Vδ2 T cells in PBMCs by activating γδ T-cell receptor (γδTCR) and Toll-like receptor (TLR) 7/8 using isopentenyl pyrophosphate (IPP) and resiquimod, respectively, and tested the functional markers and antitumoral effects in vitro two-dimensional two-dimensional and three-dimensional spheroid models and in vivo models. Single-cell sequencing dataset analysis and reverse-phase protein array were employed for mechanistic studies.

RESULTS:

We find that Vδ2 T cells expanded by IPP plus resiquimod showed significantly increased cytotoxicity to tumor cells with lower programmed cell death protein 1 (PD-1) expression than Vδ2 T cells expanded by IPP or ZOL. Mechanistically, the costimulation enhanced the activation of the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB/Akt)-the mammalian target of rapamycin (mTOR) pathway and the TLR7/8-MyD88 pathway. Resiquimod stimulated Vδ2 T-cell expansion in both antigen presenting cell dependent and independent manners. In addition, resiquimod decreased the number of adherent inhibitory antigen-presenting cells (APCs) and suppressed the inhibitory function of APCs by decreasing PD-L1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression in these cells during in vitro Vδ2 T-cell expansion. Finally, we showed that human Vδ2 T cells can be expanded from PBMCs and spleen of humanized NSG mice using IPP plus resiquimod or ZOL, demonstrating that humanized mice are a promising preclinical model for studying human γδ T-cell development and function.

CONCLUSIONS:

Vδ2 T cells expanded by IPP and resiquimod demonstrate improved anti-tumor function and have the potential to increase the efficacy of γδ T cell-based therapies.

• Authors: Huaishan Wang, Hui Chen, Shujing Liu, Jie Zhang, Hezhe Lu, Rajasekharan Somasundaram, Robin Choi, Gao Zhang, Lingling Ou, John Scholler, Shifu Tian, Liyun Dong, Guo Yeye, Lili Huang, Thomas Connelly, Ling Li, Alexander Huang, Tara C Mitchell, Yi Fan, Carl H June, Gordon B Mills, Wei Guo, Meenhard Herlyn, Xiaowei Xu
• Journal: Journal for immunotherapy of cancer (J Immunother Cancer) Vol. 9 Issue 12 (12 2021) ISSN: 2051-1426 [Electronic] England
• PMID: 34937742 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Chemical References

• Receptors, Antigen, T-Cell, gamma-delta
• TLR7 protein, human
• Toll-Like Receptor 7
• MTOR protein, human
• TOR Serine-Threonine Kinases

Topics

• Animals
• Humans
• Immunotherapy (methods)
• Melanoma (genetics, pathology)
• Mice
• Mice, Nude
• Receptors, Antigen, T-Cell, gamma-delta (metabolism)
• TOR Serine-Threonine Kinases (metabolism)
• Toll-Like Receptor 7 (metabolism)