Project description:NK cells and CD8+ T cells both contribute to HIV-1 control. These cells not only suppress HIV-1 replication, but also select HIV-1 escape mutant viruses. Most viruses bearing T cell escape mutations are expected to remain susceptible to NK cell suppression, but their control by NK cells is unclear. We investigated the role of HIV-1-specific CD8+ T cells and NK cells recognizing superimposed Pol peptides in selection and control of HIV-1 mutant virus. KIR2DL2+ NK cells had an enhanced ability to recognize HIV-1-infected cells after selection of Pol mutant virus by PolIY11-specific HLA-C*12:02-restricted T cells. Mass spectrometry-based immunopeptidome profiling of HIV-1-infected cells and analysis of crystal structures of TCR- and KIR2DL2-HLA-C*12:02-peptide complexes demonstrated the molecular basis for selection and recognition of the escape mutant epitope by TCR and KIR2DL2. The present study elucidates the mechanism for selection and control of an HIV-1 escape virus by T cells and NK cells.
Project description:In an unbiased transcriptomic screen we observed reduced NK cell activation phenotypes in HLA-B*46 positive people with HIV. These findings show that contemporaneous treated cohorts can be used to analyze host genetic effects in HIV disease, and support a role for NK cells in HIV control revealed by unique properties of the recombinant HLA-B*46 allele which is frequent only in Asia.
Project description:B cell follicles (BCF) in the lymph node are a major sanctuary for HIV reservoirs. Immune regulatory mechanisms hindering cytolytic CD8+ responses at these sites, are poorly characterized, likely enabling HIV persistence. Spatial transcriptomics and high- dimensional histocytometry were used to define CD8+ T cell function and immune regulation in LN follicles of people Living with HIV (PLWH), at various stages of ART- treatment. Histocytometry demonstrated that CD8+ T cells infiltrating BCF mostly lacked granzyme B expression, coinciding with reduced chromatin access at cytolytic gene loci in dissociated lymph node cells. Spatial transcriptomics confirmed the immune regulatory microenvironment of HIV-infected BCF, particularly exhibiting upregulation of HLA-E. Additional FACS analysis identified a subset of LN CD8+ T cells expressing the NKG2A-interacting partner of HLA-E, with reduced granzyme B expression. These findings reveal regulation of follicular CD8+ T cells at the HLA-E- NKG2A axis as a key mechanism for HIV immune evasion.
Project description:Unlike HIV infection, which progresses to AIDS absent suppressive anti-retroviral therapy (ART), nonpathogenic infections in natural hosts, such African green monkeys (AGMs), are characterized by a lack of gut microbial translocation and robust secondary lymphoid Natural Killer (NK) cell responses resulting in absence of chronic inflammation and limited SIV dissemination in lymph nodes (LN) B-cell-follicles, respectively. In a pathogenic infection model (i.e. ART-treated, SIVmac239-infected rhesus macaques; RMs), sequential Interleukin (IL)-21 and interferon (IFN)-alpha therapy generated terminally-differentiated blood NK cells (NKG2a/clowCD16+) with potent HLA-E-restricted activity in response to SIV-ENV peptides in contrast to control RMs, where less differentiated, IFN-gamma+ NK cells predominated. The frequency and cytolytic activity of NKG2a/clowCD16+ NK cells correlated with a reduction of replication-competent SIV in LN during ART and viral rebound delay following analytical treatment interruption. These data demonstrate that AGM-like NK cell differentiation profiles can be rescued in RMs to promote viral clearance in tissues.
Project description:Unlike HIV infection, which progresses to AIDS absent suppressive anti-retroviral therapy (ART), nonpathogenic infections in natural hosts, such African green monkeys (AGMs), are characterized by a lack of gut microbial translocation and robust secondary lymphoid Natural Killer (NK) cell responses resulting in absence of chronic inflammation and limited SIV dissemination in lymph nodes (LN) B-cell-follicles, respectively. In a pathogenic infection model (i.e. ART-treated, SIVmac239-infected rhesus macaques; RMs), sequential Interleukin (IL)-21 and interferon (IFN)-alpha therapy generated terminally-differentiated blood NK cells (NKG2a/clowCD16+) with potent HLA-E-restricted activity in response to SIV-ENV peptides in contrast to control RMs, where less differentiated, IFN-gamma+ NK cells predominated. The frequency and cytolytic activity of NKG2a/clowCD16+ NK cells correlated with a reduction of replication-competent SIV in LN during ART and viral rebound delay following analytical treatment interruption. These data demonstrate that AGM-like NK cell differentiation profiles can be rescued in RMs to promote viral clearance in tissues.
Project description:Unlike HIV infection, which progresses to AIDS absent suppressive anti-retroviral therapy (ART), nonpathogenic infections in natural hosts, such African green monkeys (AGMs), are characterized by a lack of gut microbial translocation and robust secondary lymphoid Natural Killer (NK) cell responses resulting in absence of chronic inflammation and limited SIV dissemination in lymph nodes (LN) B-cell-follicles, respectively. In a pathogenic infection model (i.e. ART-treated, SIVmac239-infected rhesus macaques; RMs), sequential Interleukin (IL)-21 and interferon (IFN)-alpha therapy generated terminally-differentiated blood NK cells (NKG2a/clowCD16+) with potent HLA-E-restricted activity in response to SIV-ENV peptides in contrast to control RMs, where less differentiated, IFN-gamma+ NK cells predominated. The frequency and cytolytic activity of NKG2a/clowCD16+ NK cells correlated with a reduction of replication-competent SIV in LN during ART and viral rebound delay following analytical treatment interruption. These data demonstrate that AGM-like NK cell differentiation profiles can be rescued in RMs to promote viral clearance in tissues.
Project description:Natural killer (NK) cells are lymphocytes that participate in immune responses through their cytotoxic activity and secretion of cytokines and chemokines. They can be activated by interaction with ligands on target cells or by soluble mediators such as cytokines. In addition, soluble HLA-G, a major histocompatibility complex molecule secreted by fetal trophoblast cells during early pregnancy, stimulates resting NK cells to secrete proinflammatory and proangiogenic factors. Human NK cells are abundant in uterus, where they remain after implantation. Soluble HLA-G is endocytosed into early endosomes of NK cells where its receptor, CD158d, initiates a signaling cascade through DNA-PKcs, Akt and NF-kB3. The physiological relevance of this endosomal signaling pathway, and how the fate and function of NK cells during early pregnancy is regulated, is unknown. Here we show that soluble agonists of CD158d trigger DNA damage response signaling and p21 (CIP1/WAF1) expression to promote senescence in primary NK cells. CD158d engagement resulted in morphological alterations in cell size and shape, chromatin remodeling, and survival in the absence of proliferation, all hallmarks of senescence. Microarray analysis revealed a senescence signature of upregulated genes upon sustained activation through CD158d. The proinflammatory and proangiogenic factors secreted by these metabolically active NK cells are part of a senescence associated secretory phenotype (SASP) that promoted tissue remodeling and angiogenesis as assessed by functional readouts of vascular permeability and endothelial cell tube formation. We propose that ligand-induced senescence is a molecular switch for the sustained activation of NK cells in response to soluble HLA-G for the purpose of remodeling the maternal vasculature in early pregnancy. Time series (4 hr, 16 hr, 64 hr) of NK cells treated with agonist (anti-CD158d mAb) or control. NK cells were from 4 donors.
Project description:Acute myeloid leukemia (AML) is a heterogeneous group of malignancies which may be sensitive to the natural killer (NK) cell anti-tumor response. However, NK cells are frequently defective in AML. Here, we found in an exploratory cohort (n = 46) that NK-cell status at diagnosis of AML separated patients in two groups with a different clinical outcome. Patients with a deficient NK-cell profile, including reduced expression of some activating NK receptors (e.g. DNAM-1, NKp46 and NKG2D) and decreased IFN-g production, had a significantly higher risk of relapse (P = 0.03) independently of cytogenetic classification in multivariate analysis. Patients with defective NK cells showed a profound gene expression decrease in AML blasts for cytokine and chemokine signaling (e.g. IL15, IFNGR1, IFNGR2, CXCR4), antigen processing (e.g. HLA-DRA, HLA-DRB1, CD74) and adhesion molecule pathways (e.g. PVR, ICAM1). A set of 388 leukemic classifier genes defined in the exploratory cohort was independently validated in a multicentric cohort of 194 AML patients. In total, these data evidenced the interplay between NK-cells and AML blasts at diagnosis allowing an immune-based stratification of AML patients independently of clinical classifications. 5 normal AML cells were compared with 8 NK deficient AML cells.