Single-cell RNA sequencing identifies a population of human liver-type ILC1s.

Group 1 innate lymphoid cells (ILCs) comprise a heterogeneous family of cytotoxic natural killer (NK) cells and ILC1s. We identify a population of "liver-type" ILC1s with transcriptional, phenotypic, and functional features distinct from those of conventional and liver-resident NK cells as well as from other previously described human ILC1 subsets. LT-ILC1s are CD49aCD94CD200R1, express the transcription factor T-BET, and do not express the activating receptor NKp80 or the transcription factor EOMES.

HIV-Associated Microbial Translocation May Affect Cytokine Production of CD56bright NK Cells via Stimulation of Monocytes.

The mechanisms involved in HIV-associated natural killer (NK) cell impairment are still incompletely understood. We observed HIV infection to be associated with increased plasma levels of IFABP, a marker for gut epithelial barrier dysfunction, and LBP, a marker for microbial translocation. Both IFABP and LBP plasma concentrations were inversely correlated with NK cell interferon-γ production, suggesting microbial translocation to modulate NK cell functions.

Natural Killer Cell-Mediated Antibody-Dependent Cellular Cytotoxicity Against SARS-CoV-2 After Natural Infection Is More Potent Than After Vaccination.

We compared the ability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike-specific antibodies to induce natural killer cell-mediated antibody-dependent cellular cytotoxicity (ADCC) in patients with natural infection and vaccinated persons. Analyzing plasma samples from 39 coronavirus disease 2019 (COVID-19) patients and 11 vaccinated individuals, significant induction of ADCC could be observed over a period of more than 3 months in both vaccinated and recovered individuals. Although plasma antibody concentrations were lower in recovered patients, we found antibodies elicited by natural infection induced a significantly stronger ADCC response compared to those induced by vaccination, which may affect protection conferred by vaccination.

Mitochondrial Dysfunction Contributes to Impaired Cytokine Production of CD56bright Natural Killer Cells From Human Immunodeficiency Virus-Infected Individuals Under Effective Antiretroviral Therapy.

Human immunodeficiency virus (HIV) infection is associated with impaired natural killer (NK) cell activity, which is only incompletely restored under antiretroviral therapy. Analyzing the bioenergetics profiles of oxygen consumption, we observed that several parameters were significantly reduced in HIV+ NK cells, indicating a mitochondrial defect. Accordingly, we found HIV+ CD56bright NK cells to display a decreased mitochondrial membrane potential and mitochondrial mass.

IL-28B Genetic Variants Determine the Extent of Monocyte-Induced Activation of NK Cells in Hepatitis C.

Background: Immuno-genetic studies suggest a functional link between NK cells and λ-IFNs. We recently showed that NK cells are negative for the IFN-λ receptor IFN-λR1 and do not respond to IFN-λ, suggesting a rather indirect association between IL-28B genotype and NK cell activity.

Methods: A total of 75 HCV(+) patients and 67 healthy controls were enrolled into this study.

Hypoxia impairs anti-viral activity of natural killer (NK) cells but has little effect on anti-fibrotic NK cell functions in hepatitis C virus infection.

Background & Aims: Natural killer (NK) cells have been shown to exert anti-viral as well as anti-fibrotic functions in hepatitis C virus (HCV) infection. Previous studies, however, analyzed NK cell functions exclusively under atmospheric oxygen conditions despite the fact that the liver microenvironment is hypoxic. Here, we analyzed the effects of low oxygen tension on anti-viral and anti-fibrotic NK cell activity.