Chronic stimulation drives human NK cell dysfunction and epigenetic reprograming

• Published in: The Journal of clinical investigation 2019-09, Vol.130 (9), p.3770-3785
• Main Authors: Merino, Aimee, Zhang, Bin, Dougherty, Philip, Luo, Xianghua, Wang, Jinhua, Blazar, Bruce R, Miller, Jeffrey S, Cichocki, Frank
• Format: Article
• Language: English
• Subjects: Antigens; B cells; Biomedical research; Cancer immunotherapy; Cancer research; CD223 antigen; CD3 antigen; CD57 antigen; CD8 antigen; Cell proliferation; Cytokines; Cytomegalovirus; Deoxyribonucleic acid; DNA; DNA methylation; Endothelial cells; Endothelium; Epigenetic inheritance; Epigenetics; Genetic research; Genomes; Genomics; Health aspects; Immune checkpoint; Immunological memory; Immunotherapy; Infection; Infections; Interleukin 15; Killer cells; Lymphocytes; Lymphocytes T; Memory cells; Methylation; Natural killer cells; NKG2 antigen; PD-1 protein; Peptides; Software industry; T cells; Transcription factors; Tumors
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/jci125916

A population of Natural Killer (NK) cells expressing the activating receptor NKG2C and the maturation marker CD57 expands in response to human cytomegalovirus (HCMV) infection. CD3-CD56dimCD57+NKG2C+ NK cells are similar to CD8+ memory T cells with rapid and robust effector function upon re-stimulation, persistence, and epigenetic remodeling of the IFNG locus. Chronic antigen stimulation drives CD8+ memory T cell proliferation while also inducing genome-wide epigenetic reprograming and dysfunction. We hypothesized that chronic stimulation could similarly induce epigenetic reprograming and dysfunction in NK cells. Here we show that chronic stimulation of adaptive NK cells through NKG2C using plate-bound agonistic antibodies in combination with IL-15 drove robust proliferation and activation of CD3-CD56dimCD57+NKG2C+ NK cells while simultaneously inducing high expression of the checkpoint inhibitory receptors LAG-3 and PD-1. Marked induction of checkpoint inhibitory receptors was also observed on the surface of adaptive NK cells co-cultured with HCMV-infected endothelial cells. Chronically stimulated adaptive NK cells were dysfunctional when challenged with tumor targets. These cells exhibited a pattern of epigenetic reprograming, with genome-wide alterations in DNA methylation. Our study has important implications for cancer immunotherapy and suggest that exhausted NK cells could be targeted with inhibitory checkpoint receptor blockade.