NK cells reduce anergic T cell development in early-stage tumors by promoting myeloid cell maturation

Robin S Lindsay; Marit M Melssen; Katarzyna Stasiak; Jessica L Annis; Amber N Woods; Anthony B Rodriguez; Michael G Brown; Victor H Engelhard

doi:10.3389/fonc.2022.1058894

NK cells reduce anergic T cell development in early-stage tumors by promoting myeloid cell maturation

Front Oncol. 2022 Dec 2:12:1058894. doi: 10.3389/fonc.2022.1058894. eCollection 2022.

Authors

Robin S Lindsay^{1

2}, Marit M Melssen^{1

2}, Katarzyna Stasiak^{1

2}, Jessica L Annis^{1

2}, Amber N Woods^{1

2}, Anthony B Rodriguez^{1

2}, Michael G Brown^{1

2

3}, Victor H Engelhard^{1

2}

Affiliations

¹ Beirne B. Carter Center for Immunology Research, University of Virginia School of Medicine, Charlottesville, VA, United States.
² Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, United States.
³ Division of Nephrology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, United States.

Abstract

Introduction: Studies of NK cells in tumors have primarily focused on their direct actions towards tumor cells. We evaluated the impact of NK cells on expression of homing receptor ligands on tumor vasculature, intratumoral T cell number and function, and T cell activation in tumor draining lymph node.

Methods: Using an implantable mouse model of melanoma, T cell responses and homing receptor ligand expression on the vasculature were evaluated with and without NK cells present during the early stages of the tumor response by flow cytometry.

Results: NK cells in early-stage tumors are one source of IFNγ that augments homing receptor ligand expression. More significantly, NK cell depletion resulted in increased numbers of intratumoral T cells with an anergic phenotype. Anergic T cell development in tumor draining lymph node was associated with increased T-cell receptor signaling but decreased proliferation and effector cell activity, and an incomplete maturation phenotype of antigen presenting cells. These effects of NK depletion were similar to those of blocking CD40L stimulation.

Discussion: We conclude that an important function of NK cells is to drive proper APC maturation via CD40L during responses to early-stage tumors, reducing development of anergic T cells. The reduced development of anergic T cells resulting in improved tumor control and T cell responses when NK cells were present.

Keywords: B16 melanoma; CD40L blockade; anergic T cells; antigen presenting cell (APC); natural killer (Nk) cell.

Abstract

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