Project description:NK cells are major innate and adaptive responders to malaria, with multiple roles in protection. Function of NK cells is heterogeneous, underpinned by expression of a diversity of receptors. One driver of NK cell heterogeneity is latent CMV infection, which drives the expansion of memory-like NK cells. We have recently reported that latent CMV infection can negatively impact the adaptive immune response to malaria, but whether CMV-mediated changes to the NK cell compartment also impact responses to malaria is unknown. Methods: We investigated the impact of latent CMV infection on NK cell response to the malaria parasite Plasmodium falciparum in vitro, and in CMV seronegative and seropositive individuals during controlled human malaria infection. We analysed NK cell activation, cytotoxicity and NK cell receptor expression. Additionally, we investigated the impact of CMV serostatus on cytokine production in response to TLR stimulation in the myeloid cell compartment. The impact of CMV and NK cell responses on malaria symptoms and parasite control and symptoms of malaria was investigated. Results: NK cells from CMV seropositive individuals had reduced responsiveness to P. falciparum parasites in vitro and had reduced activation during controlled human infection. Reduced activation was not restricted to NK subsets modulated by CMV but occurred across the entire NK cell compartment. Consistent with global NK cell attenuation, IL-12 production from myeloid cells, a response that supports NK cell activation on exposure to P. falciparum parasites, was lower in CMV infected individuals. Linking NK cell activation to clinical outcomes, NK cells expressing perforin were strongly associated with parasite control in CMV seronegative individuals. Conclusion: CMV infection modulates NK cell responses during malaria by disruption of IL-12, leading to reduced parasite control.
Project description:Cytomegalovirus (CMV) infection is ubiquitous; though often unnoticed in healthy adults it is a leading cause of neurodisability in neonates/ infants. NK and CD8 T cell cytolysis control CMV; yet their coordinate response to CMV remains uncharacterized, particularly in infants. We interrogated how NK and CD8 T cell responses differed between adults and infants in a murine CMV (MCMV) infection model. NK and CD8 T cells both limited infant MCMV infection morbidity. Notably, adult and infant NK cells effectuate discrete responses to MCMV infection with the latter preferentially forming memory associated with transcriptional distinctions prior to infection. Adoptive transfer studies further revealed that infant T cells are effector-biased but acquire the capacity to form memory in an age-dependent manner. Infant T cells' restricted ability to form memory was associated with a unique transcriptional state before and after infection. Further, acquisition of T cell memory capacity coincided with an age-dependent waning in the induction of adaptive NK cells. Our data suggests non-redundant roles for NK and CD8 T cells in MCMV infection during infancy, as NK cells compensate for the limited establishment of memory T cell subsets.
Project description:Cytomegalovirus (CMV) infection is ubiquitous; though often unnoticed in healthy adults it is a leading cause of neurodisability in neonates/ infants. NK and CD8 T cell cytolysis control CMV; yet their coordinate response to CMV remains uncharacterized, particularly in infants. We interrogated how NK and CD8 T cell responses differed between adults and infants in a murine CMV (MCMV) infection model. NK and CD8 T cells both limited infant MCMV infection morbidity. Notably, adult and infant NK cells effectuate discrete responses to MCMV infection with the latter preferentially forming memory associated with transcriptional distinctions prior to infection. Adoptive transfer studies further revealed that infant T cells are effector-biased but acquire the capacity to form memory in an age-dependent manner. Infant T cells' restricted ability to form memory was associated with a unique transcriptional state before and after infection. Further, acquisition of T cell memory capacity coincided with an age-dependent waning in the induction of adaptive NK cells. Our data suggests non-redundant roles for NK and CD8 T cells in MCMV infection during infancy, as NK cells compensate for the limited establishment of memory T cell subsets.
Project description:Previous research on adaptive NK cells in rhesus macaques suffered from the lack of specific antibodies to differentiate between inhibitory CD94/NKG2A and stimulatory CD94/NKG2C heterodimeric receptors. Recently we reported an expansion of NKG2C receptor-encoding genes in rhesus macaques, but their expression and functional role on primary NK cells remained unknown due to this deficit. Thus, we established monoclonal antibodies 4A8 and 7B1 which show identical specificities and bind to both NKG2C-1 and NKG2C-2 but neither react with NKG2C-3 nor NKG2A on transfected cell lines. Using a combination of 4A8 and Z199 antibodies in multicolor flow cytometry we detected broad expression (4-73%) of NKG2C-1 and/or NKG2C-2 (NKG2C-1/2) on primary NK cells in rhesus macaques from our breeding colony. Stratifying our data to CMV-positive and CMV-negative animals, we noticed a higher proportion (23-73%) in primary NK cells expressing NKG2C-1/2 in CMV+ as compared to CMV- macaques (4-5%). These NKG2C-1/2-positive NK cells in CMV+ macaques are characterized by lower expression of IL12RB2, ZBTB16 and SH2D1B as well as high expression of IFN-gamma, indicating that antibody 4A8 detects CMV-associated adaptive NK cells. Single cell RNA seq data of 4A8-positive NK cells from a CMV-positive individual demonstrated that a high proportion of these adaptive NK cells transcribe in addition to NKG2C-1/2 also NKG2C-3, but interestingly NKG2A as well. Remarkably, NKG2C-1 and in particular NKG2C-2 have a higher affinity to Mamu-E as compared to NKG2A. Primary NK cells exposed to Mamu-E-expressing target cells displayed strong degranulation as well as IFN-gamma expression of 4A8+ adaptive NK cells of rhCMV+ animals that was not evident in rhCMV- animals. Thus, despite co-expression of inhibitory and stimulatory CD94/NKG2 receptors the higher number of different stimulatory NKG2C receptors and their higher binding avidity to Mamu-E outreach inhibitory signaling via NKG2A. These data demonstrate the evolutionary conservation of the CMV-driven development of NKG2C-positive adaptive NK cells with particular molecular signatures in primates and with changes in gene copy numbers and regulation and in ligand binding strength of NKG2C isotypes. Thus, rhesus macaques represent a suitable and valuable nonhuman primate animal model to study the CMV-NKG2C liaison in vivo.
Project description:Epigenetic landscapes can provide insight into regulation of gene expression and cellular diversity. Here, we examined the transcriptional and epigenetic profiles of seven human blood NK cell populations, including adaptive NK cells. The BCL11B gene, encoding a transcription factor (TF) essential for T cell development and function, was the most extensively regulated, with expression increasing throughout NK cell differentiation. Several Bcl11b-regulated genes associated with T cell-signaling were specifically expressed in adaptive NK cell subsets. Regulatory networks revealed reciprocal regulation at distinct stages of NK cell differentiation, with Bcl11b repressing RUNX2 and ZBTB16 in canonical and adaptive NK cells, respectively. A critical role for Bcl11b in driving NK cell differentiation was corroborated in BCL11B mutated patients and by ectopic Bcl11b expression. Moreover, Bcl11b was required for adaptive NK cell responses in a murine CMV model, supporting expansion of these cells. Together, we define the TF regulatory circuitry of human NK cells and uncover a critical role for Bcl11b in promoting NK cell differentiation and function.
Project description:As humans age their memory T cell compartment expands due to lifelong exposure to antigens. This expansion is characterized by the presence of terminally differentiated CD8+ T cells (Temra) which possess an NK cell-like phenotype and are associated with chronic inflammatory conditions. Temra cells are predominantly driven by sporadic cytomegalovirus reactivation (CMV) yet their cellular heterogeneity remains understudied. To address this gap we measured their gene expression profiles and conducted single-cell transcriptome analysis. We show that CD8+ Temra cells are highly heterogeneous and describe subsets specific to old age and CMV infection.
Project description:The mechanisms underlying human NK cell phenotypic and functional heterogeneity are unknown. Here, we describe 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. Intriguingly, geneome-wide analyses revealed patterns of DNA methylation that were strikingly similar between CMV-associated adaptive NK cells and cytotoxic effector CD8+ T cells, but differed from those of canonical NK cells.
Project description:As humans age, their memory T cell compartment expands due to the lifelong exposure to antigens. This expansion is characterized by the presence of terminally differentiated CD8+ T cells (Temra), which possess NK cell-like phenotype and are associated with chronic inflammatory conditions. Temra cells are predominantly driven by the sporadic reactivation of cytomegalovirus (CMV), yet their epigenomic patterns and cellular heterogeneity remain understudied. To address this gap, we correlated their gene expression profiles with chromatin openness and conducted single-cell transcriptome analysis, comparing them to other CD8+ subsets and CMV-responses.