Chronic stimulation drives human NK cell dysfunction and epigenetic reprograming

Abstract

Conflict of interest:FC consults for Fate Therapeutics and has received research funds from this relationship. JSM serves on the Scientific Advisory Board (SAB) and consults for GT BioPharma and Fate Therapeutics. He has received research funds from these relationships. JSM also serves on the SAB for CytoSen and Onkimmune. BRB declares a financial conflict with Tmunity and Kadmon Corporation. He also serves on the SAB for GT Biopharma, Magenta Therapeutics, and Five Prime Therapeutics. He consults for Regeneron and Equillium Inc. None of these companies had a role in funding this research. All conflicts are managed according to institutional policies. Figure 1. Chronic stimulation through NKG2C expands adaptive NK cells. CD3/CD19-depleted PBMCs from HCMV-seropositive donors were cultured for 7 days with 10 ng/ml IL-15 and PBS, IgG2b isotype Ab, anti-NKG2A/C Ab, or anti-NKG2C Ab. (A) Representative FACS plots and summary data showing the percentages of NK cell subsets defined by expression of CD57 and NKG2C before and after a 7-day culture (n = 7). Results are from 3 independent experiments. (B) NK cells were labeled with CellTrace dye prior to culturing. Shown are FACS plots of representative donor cells stratified by CD57 and NKG2C expression and summary data (n = 6). Results are from 3 independent experiments. *P ≤ 0.05 by paired t test. P values for multiple group comparisons (A, each group vs. PBS; B, each group vs. IgG2b isotype Ab) were adjusted using the Hommel method.Study approval. The present studies involving the use of human peripheral blood products were reviewed and approved by the IRB of the University of Minnesota under protocol 9709M00134. All blood donors provided informed consent prior to donation according to Memorial Blood Bank policies. All blood samples were deidentified prior to arrival in the laboratory.

Unleashing Natural Killer Cells in the Tumor Microenvironment–The Next Generation of Immunotherapy?

“…This may suggest a role for LAG-3 in the NK cell maturation and receptor repertoire, affecting the cell's capacity to distinguish between MHC-I matched healthy and transformed cells, but not in directly inhibiting NK cell killing efficacy. By contrast, a recent report showed that chronic stimulation of adaptive NK cells from HCMV seropositive donors via NKG2C and IL-15, NKp30, or NKG2D increased PD-1 and LAG-3 surface expression, downregulating NK activity during subsequent interactions with tumor targets (136). These experiments provide primary evidence of LAG-3 as a potential exhaustion marker on NK cells following chronic stimulation.…”

LAG3 is a Central Regulator of NK Cell Cytokine Production

“…NK cells expressing NKG2C and CD57 were described following chronic stimulation of activating receptors. These exhibited an exhausted phenotype and co-expressed PD-1, TIM3 and LAG3 (26,27). In our analysis a small subset of NK cells expressing PD-1 and TIM3 inhibitory receptors also co-expressed LAG3.…”

IL-15 re-programming compensates for NK cell mitochondrial dysfunction in HIV-1 infection

“…Upregulation of inhibitory molecules on NK cells could also serve as a pathway supressing their metabolic fitness. Recently chronic stimulation of adaptive NKG2C+ NK cells in vitro led to a marked induction of checkpoint inhibitory receptors PD-1 and lymphocyte activation gene-3 (LAG-3) sharing epigenetically driven programmes with exhausted CD8 T cells (Merino et al, 2019). Moreover, a role for LAG-3 in regulating CD4 T cell metabolism and mitochondrial biogenesis has been identified (Previte et al, 2019).…”

“…While these attributes are considered important in the functional specialisation of these NK cells, the development of these features under conditions of continuous stimulation/persistent inflammation during HIV-1 infection could lead to the establishment of functionally and metabolically exhausted NK cells akin to exhausted CD8 T cells. In keeping with this notion, chronic stimulation of adaptive NK cells through NKG2C ligation was recently found to lead to a molecular programme of exhaustion that is shared between NK cells and CD8 T cells (Merino et al, 2019). Exhausted CD8 T cells are characterised by a number of metabolic defects, however, to date it remains unexplored how persistent HIV-1 infection contributes to the metabolic remodelling of NK cell subsets.…”