During human CMV infection, there is a preferential expansion of natural killer (NK) cells expressing the activating CD94–NKG2C receptor complex, implicating this receptor in the recognition of ...CMV-infected cells. We hypothesized that NK cells expanded in response to pathogens will be marked by expression of CD57, a carbohydrate antigen expressed on highly mature cells within the CD56dimCD16+ NK cell compartment. Here we demonstrate the preferential expansion of a unique subset of NK cells coexpressing the activating CD94–NKG2C receptor and CD57 in CMV+ donors. These CD57+NKG2Chi NK cells degranulated in response to stimulation through their NKG2C receptor. Furthermore, CD57+NKG2Chi NK cells preferentially lack expression of the inhibitory NKG2A receptor and the inhibitory KIR3DL1 receptor in individuals expressing its HLA-Bw4 ligand. Moreover, in solid-organ transplant recipients with active CMV infection, the percentage of CD57+NKG2Chi NK cells in the total NK cell population preferentially increased. During acute CMV infection, the NKG2C+ NK cells proliferated, became NKG2Chi, and finally acquired CD57. Thus, we propose that CD57 might provide a marker of "memory" NK cells that have been expanded in response to infection.
Latent replication-competent HIV-1 persists in individuals on long-term antiretroviral therapy (ART). We developed the Full-Length Individual Proviral Sequencing (FLIPS) assay to determine the ...distribution of latent replication-competent HIV-1 within memory CD4+ T cell subsets in six individuals on long-term ART. FLIPS is an efficient, high-throughput assay that amplifies and sequences near full-length (∼9 kb) HIV-1 proviral genomes and determines potential replication competency through genetic characterization. FLIPS provides a genome-scale perspective that addresses the limitations of other methods that also genetically characterize the latent reservoir. Using FLIPS, we identified 5% of proviruses as intact and potentially replication competent. Intact proviruses were unequally distributed between T cell subsets, with effector memory cells containing the largest proportion of genetically intact HIV-1 proviruses. We identified multiple identical intact proviruses, suggesting a role for cellular proliferation in the maintenance of the latent HIV-1 reservoir.
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•FLIPS utilizes NGS to sequence and genetically characterize HIV-1 proviruses•FLIPS identifies genetically intact and likely replication-competent HIV-1 proviruses•Identical HIV-1 proviruses suggest maintenance of reservoir by cellular proliferation•Demonstrate the advantages of FLIPS over other common HIV-1 sequencing assays
Latent, replication-competent HIV-1 proviruses pose a significant barrier to an HIV-1 cure. Hiener et al. present the Full-Length Individual Proviral Sequencing (FLIPS) assay to reveal the distribution of genetically intact and potentially replication-competent HIV-1 proviruses in different T cell subsets isolated from individuals on long-term antiretroviral therapy.
To investigate the possibility that HIV-1 replication in lymph nodes sustains the reservoir during ART, we looked for evidence of viral replication in 5 donors after up to 13 years of viral ...suppression. We characterized proviral populations in lymph nodes and peripheral blood before and during ART, evaluated the levels of viral RNA expression in single lymph node and blood cells, and characterized the proviral integration sites in paired lymph node and blood samples. Proviruses with identical sequences, identical integration sites, and similar levels of RNA expression were found in lymph nodes and blood samples collected during ART, and no single sequence with significant divergence from the pretherapy population was present in either blood or lymph nodes. These findings show that all detectable persistent HIV-1 infection is consistent with maintenance in lymph nodes by clonal proliferation of cells infected before ART and not by ongoing viral replication during ART.
Prolonged chronic stress has deleterious effects on immune function and is associated with numerous negative health outcomes. The spleen harbors one-fourth of the body's lymphocytes and mediates both ...innate and adaptive immune responses. However, the subset of splenic lymphocytes that respond, either adaptively or maladaptively, to various stressors remains largely unknown. Here we investigated the effects of unpredictable chronic mild stress (CMS) exposure on spleen composition in male mice housed in two different caging conditions: standard caging (Cntl) and enriched environment (EE). EE-caged mice exhibited the greatest absolute number of splenocytes and CMS exposure significantly lowered splenocyte numbers in both caging conditions. Glucocorticoid production, measured by mean fecal corticosterone metabolites (FCM), was significantly lower in EE-caged mice vs. Cntl-caged mice. Surprisingly, CMS exposure resulted in an increase in mean FCM in EE-caged mice, but no significant change in Cntl-caged mice. CMS altered the splenic B:T lymphocyte ratio; it reduced the frequency of B cells, but increased the frequency of T cells in EE-caged mice. Splenocyte number and B:T lymphocyte ratio showed a negative relationship with mean FCM. EE-caged mice had a lower frequency of immature and germinal B cells than Cntl-caged mice. CMS markedly increased the frequency of immature and marginal zone B cells, but decreased the frequency of follicular B cells in both caging conditions. Mean FCM correlated positively with frequency of immature, marginal zone and germinal center B cells, but negatively with frequency of follicular B cells. To conclude, splenic immune cells, particularly B lymphocyte composition, are modulated by caging environment and stress and may prime mice differently to respond to immune challenges.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Plasma human immunodeficiency virus type 1 (HIV-1) RNA levels in women are lower early in untreated HIV-1 infection compared with those in men, but women have higher T-cell activation and faster ...disease progression when adjusted for viral load. It is not known whether these sex differences persist during effective antiretroviral therapy (ART), or whether they would be relevant for the evaluation and implementation of HIV-1 cure strategies. We prospectively enrolled a cohort of reproductive-aged women and matched men on suppressive ART and measured markers of HIV-1 persistence, residual virus activity, and immune activation. The frequency of CD4+ T cells harboring HIV-1 DNA was comparable between the sexes, but there was higher cell-associated HIV-1 RNA, higher plasma HIV-1 (single copy assay), and higher T-cell activation and PD-1 expression in men compared with women. These sex-related differences in immune phenotype and HIV-1 persistence on ART have significant implications for the design and measurement of curative interventions.
Chronic HIV infection is characterized by increased immune activation and immunosenescence. p16 INK4a (p16) is a member of the cyclin-dependent kinase antagonist family that inhibits cellular ...proliferation, and its protein expression increases during normal chronological aging. However, some infectious diseases can increase the expression of this anti-proliferative protein, potentially accelerating immunological aging and dysfunction. In order to investigate the immunological aging in HIV patients, p16 protein expression was evaluated by flow cytometry, in T cell subsets in a cohort of chronically HIV-infected patients on and off ART as well as age-matched healthy controls. Results showed that untreated HIV-infected subjects exhibited increased per-cell p16 protein expression that was discordant with chronological aging. ART restored p16 protein expression to levels comparable with HIV-negative subjects in the CD4 compartment, but not in CD8 T cells, which can be an indicative of an irreversible activation/exhaustion status on these cells. Additionally, the frequency of activated CD4+ and CD8+ T cells was positively correlated with p16 expression in CD4+ and CD8+ T cells in untreated subjects. In contrast to healthy controls, untreated HIV-infected individuals had increased p16 levels within the effector memory (TEM) subset, indicating a possible role for this marker in impaired clonal expansion during antiviral effector function. Taken together, these data demonstrate that chronic HIV infection is associated with elevated expression of the cellular aging marker p16 in T cells. ART restored normal p16 levels in the CD4+ T cell compartment, indicating that use of therapy can be of fundamental importance to normal cell cycling and maintaining immune homeostasis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objective
To determine whether adding mindfulness‐based eating and stress management practices to a diet‐exercise program improves weight loss and metabolic syndrome components.
Methods
In this study ...194 adults with obesity were randomized to a 5.5‐month program with or without mindfulness training and identical diet‐exercise guidelines. Intention‐to‐treat analyses with multiple imputation were used for missing data. The primary outcome was 18‐month weight change.
Results
Estimated effects comparing the mindfulness to control arm favored the mindfulness arm in (a) weight loss at 12 months, −1.9 kg (95% CI: −4.5, 0.8; P = 0.17), and 18 months, −1.7 kg (95% CI: −4.7, 1.2; P = 0.24), though not statistically significant; (b) changes in fasting glucose at 12 months, −3.1 mg/dl (95% CI: −6.3, 0.1; P = 0.06), and 18 months, −4.1 mg/dl (95% CI: −7.3, −0.9; P = 0.01); and (c) changes in triglyceride/HDL ratio at 12 months, −0.57 (95% CI: −0.95, −0.18; P = 0.004), and 18 months, −0.36 (95% CI: −0.74, 0.03; P = 0.07). Estimates for other metabolic risk factors were not statistically significant, including waist circumference, blood pressure, and C‐reactive protein.
Conclusions
Mindfulness enhancements to a diet‐exercise program did not show substantial weight loss benefit but may promote long‐term improvement in some aspects of metabolic health in obesity that requires further study.
Latently-infected CD4+ T cells are widely considered to be the major barrier to a cure for HIV. Much of our understanding of HIV latency comes from latency models and blood cells, but most ...HIV-infected cells reside in lymphoid tissues such as the gut. We hypothesized that tissue-specific environments may impact the mechanisms that govern HIV expression. To assess the degree to which different mechanisms inhibit HIV transcription in the gut and blood, we quantified HIV transcripts suggestive of transcriptional interference (U3-U5; "Read-through"), initiation (TAR), 5' elongation (R-U5-pre-Gag; "Long LTR"), distal transcription (Nef), completion (U3-polyA; "PolyA"), and multiple splicing (Tat-Rev) in matched peripheral blood mononuclear cells (PBMCs) and rectal biopsies, and matched FACS-sorted CD4+ T cells from blood and rectum, from two cohorts of ART-suppressed individuals. Like the PBMCs, rectal biopsies showed low levels of read-through transcripts (median = 23 copies/106 cells) and a gradient of total (679)>elongated(75)>Nef(16)>polyadenylated (11)>multiply-spliced HIV RNAs(<1) p<0.05 for all, demonstrating blocks to HIV transcriptional elongation, completion, and splicing. Rectal CD4+ T cells showed a similar gradient of total>polyadenylated>multiply-spliced transcripts, but the ratio of total to elongated transcripts was 6-fold lower than in blood CD4+ T cells (P = 0.016), suggesting less of a block to HIV transcriptional elongation in rectal CD4+ T cells. Levels of total transcripts per provirus were significantly lower in rectal biopsies compared to PBMCs (median 3.5 vs. 15.4; P = 0.008) and in sorted CD4+ T cells from rectum compared to blood (median 2.7 vs. 31.8; P = 0.016). The lower levels of HIV transcriptional initiation and of most HIV transcripts per provirus in the rectum suggest that this site may be enriched for latently-infected cells, cells in which latency is maintained by different mechanisms, or cells in a "deeper" state of latency. These are important considerations for designing therapies that aim to disrupt HIV latency in all tissue compartments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Background
Identifying where human immunodeficiency virus (HIV) persists in people living with HIV and receiving antiretroviral therapy is critical to develop cure strategies. We assessed ...the relationship of HIV persistence to expression of chemokine receptors and their chemokines in blood (n = 48) and in rectal (n = 20) and lymph node (LN; n = 8) tissue collected from people living with HIV who were receiving suppressive antiretroviral therapy.
Methods
Cell-associated integrated HIV DNA, unspliced HIV RNA, and chemokine messenger RNA were quantified by quantitative polymerase chain reaction. Chemokine receptor expression on CD4+ T cells was determined using flow cytometry.
Results
Integrated HIV DNA levels in CD4+ T cells, CCR6+CXCR3+ memory CD4+ T-cell frequency, and CCL20 expression (ligand for CCR6) were highest in rectal tissue, where HIV-infected CCR6+ T cells accounted for nearly all infected cells (median, 89.7%). Conversely in LN tissue, CCR6+ T cells were infrequent, and there was a statistically significant association of cell-associated HIV DNA and RNA with CCL19, CCL21, and CXCL13 chemokines.
Conclusions
HIV-infected CCR6+ CD4+ T cells accounted for the majority of infected cells in rectal tissue. The different relationships between HIV persistence and T-cell subsets and chemokines in rectal and LN tissue suggest that different tissue-specific strategies may be required to eliminate HIV persistence and that assessment of biomarkers for HIV persistence may not be generalizable between blood and other tissues.
The relationship between human immunodeficiency virus (HIV) persistence and proportions of CD4+ T cells expressing various chemokine receptors or their chemokines differs among anatomic sites. Rectal CCR6+ CD4+ T cells have a major contribution to the HIV reservoir in recipients of antiretroviral therapy.
In human immunodeficiency virus (HIV) infection, collagen deposition and fibrosis within the T cell zone disrupt the lymphatic tissue architecture, contributing to depletion of CD4+ T cells and ...limiting immune reconstitution. We used relevant animal and in vitro models to investigate the kinetics and possible underlying mechanism(s) of this process. In the lymphatic tissue of simian immunodeficiency virus (SIV)-infected rhesus macaques, we observed parallel increases in immune activation, transforming growth factor (TGF) β1-positive regulatory T (Treg) cells, and collagen type I deposition by 7 days after inoculation, consistent with the hypothesis that early immune activation elicits a countering Treg cell response associated with TGFβ1 expression and collagen deposition. In support of this hypothesis and the possible role of fibrosis in viral pathogenesis, we show (1) spatial colocalization and temporal concordance in levels of TGFβ1+ Treg cells and collagen deposition; (2) TGFβ1+ inducible Treg cell stimulation of primary lymphatic tissue fibroblasts to produce collagen type I in vitro; and (3) high levels of immune activation, TGFβ1+ Treg cells, and collagen deposition in pathogenic SIV infection of macaques, in contrast to apathogenic SIV infection in sooty mangabeys in which levels of immune activation, TGFβ1+ Treg cells, and collagen deposition were low. We thus conclude that the response of TGFβ1+ Treg cells to immune activation in early SIV/HIV infection is a double-edged sword: TGFβ1+ Treg cells normally have a positive effect by limiting immunopathological and autoreactive immune responses, but they also have a negative effect by dampening the antiviral immune response and, as we show here, causing deleterious effects on CD4+ T cell homeostasis by inducing collagen deposition in lymphatic tissues.
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