Project description:Natural killer (NK) cells are circulating lymphocytes that possess both innate and adaptive features, the latter including antigen-specific clonal expansion and long-lived memory responses. Unlike other adaptive lymphocytes like T and B cells, NK cells are not thought to require priming in lymphoid organs during activation. However, although NK cells respond in multiple tissue sites during cytomegalovirus (CMV) infection, here we observed that early activation and virus-specific expansion occurs predominantly in the spleen. These splenic NK cells exhibited heightened TNF-a signaling, which we identify as a novel and critical regulator of both innate and adaptive responses through engagement of distinct NF-kB signaling arms downstream of TNFR2. These findings highlight the central role of the spleen as a lymphoid organ in facilitating the innate-to-adaptive transition NK cells undergo during viral infection, and provide insight into how we can better generate innate and adaptive NK cell immunity across diverse settings. Bulk RNA-Seq data of WT Ly49H+ NK from spleen or liver on day 0 and day 1 post MCMV infection.
Project description:Natural killer (NK) cells are circulating lymphocytes that possess both innate and adaptive features, the latter including antigen-specific clonal expansion and long-lived memory responses. Unlike other adaptive lymphocytes like T and B cells, NK cells are not thought to require priming in lymphoid organs during activation. However, although NK cells respond in multiple tissue sites during cytomegalovirus (CMV) infection, here we observed that early activation and virus-specific expansion occurs predominantly in the spleen. These splenic NK cells exhibited heightened TNF-a signaling, which we identify as a novel and critical regulator of both innate and adaptive responses through engagement of distinct NF-kB signaling arms downstream of TNFR2. These findings highlight the central role of the spleen as a lymphoid organ in facilitating the innate-to-adaptive transition NK cells undergo during viral infection, and provide insight into how we can better generate innate and adaptive NK cell immunity across diverse settings. Bulk RNA-Seq data of WT or TNFR2-/- Ly49H+ NK from spleen at different time points post MCMV infection.
Project description:Natural killer (NK) cells are circulating lymphocytes that possess both innate and adaptive features, the latter including antigen-specific clonal expansion and long-lived memory responses. Unlike other adaptive lymphocytes like T and B cells, NK cells are not thought to require priming in lymphoid organs during activation. However, although NK cells respond in multiple tissue sites during cytomegalovirus (CMV) infection, here we observed that early activation and virus-specific expansion occurs predominantly in the spleen. These splenic NK cells exhibited heightened TNF-a signaling, which we identify as a novel and critical regulator of both innate and adaptive responses through engagement of distinct NF-kB signaling arms downstream of TNFR2. These findings highlight the central role of the spleen as a lymphoid organ in facilitating the innate-to-adaptive transition NK cells undergo during viral infection, and provide insight into how we can better generate innate and adaptive NK cell immunity across diverse settings. Bulk RNA-Seq data of cDC1, pDC, red pulp macrophages from spleen at different time points post MCMV infection
Project description:Adaptive features of natural killer (NK) cells have been reported in various species with different underlying mechanisms. It is unclear, however, which NK cell populations are capable of mounting antigen-specific recall responses, and how such functions are regulated at the molecular level. Here we identify and characterize a discrete population of CD49a+CD16- NK cells in the human liver that display increased epigenetic potential to elicit memory responses and has the functional properties to exert antigen-specific immunity on the skin as an effector site. Integrated chromatin-based epigenetic and transcriptomic profiling revealed unique characteristics of hepatic CD49a+CD16- NK cells when compared to conventional CD49a-CD16+ NK cells thereby defining active genomic regions and molecules underpinning distinct NK cell reactivity. In contrast to conventional NK cells, our results suggest adaptive CD49a+CD16- NK cells to be able to bypass the KIR receptor-ligand system upon antigen-specific stimulation. Furthermore, these cells were highly migratory towards chemokine gradients expressed in epicutaneous patch test lesions as an effector site of adaptive immune responses of the skin. These results define pathways operative in human antigen-specific memory NK cells and provide a roadmap for harnessing this NK cell subset for specific therapeutic or prophylactic vaccine strategies.
Project description:The mechanisms underlying human natural killer (NK) cell phenotypic and functional heterogeneity are unknown. Here, we have described the emergence of diverse subsets of human NK cells selectively lacking expression of signaling proteins following cytomegalovirus (CMV) infection. The absence of B and myeloid cell-related signaling protein expression in these NK cell subsets correlated with promoter DNA hypermethylation. Genome-wide DNA methylation patterns were strikingly similar between CMV-associated adaptive NK cells and cytotoxic effector T cells, but differed from those of canonical NK cells. Functional interrogation demonstrated altered cytokine responsiveness in adaptive NK cells that was linked to reduced expression of the transcription factor PLZF. Furthermore, subsets of adaptive NK cells demonstrated significantly reduced functional responses to activated autologous T cells. The present results uncover a spectrum of epigenetically unique adaptive NK cell subsets that diversify in response to viral infection and have distinct functional capabilities compared to canonical NK cell subsets.