Search

Over the past several years, new populations of innate lymphocytes have been described in mice and primates that are critical for mucosal homeostasis, microbial regulation, and immune defense. Generally conserved from mice to humans, innate lymphoid cells (ILC) have been divided primarily into three subpopulations based on phenotypic and functional repertoires: ILC1 bear similarities to natural killer cells; ILC2 have overlapping functions with TH2 cells; and ILC3 that share many functions with TH17/TH22 cells. ILC are specifically enriched at mucosal surfaces and are possibly one of the earliest responders during viral infections besides being involved in the homeostasis of gut-associated lymphoid tissue and maintenance of gut epithelial barrier integrity. Burgeoning evidence also suggests that there is an early and sustained abrogation of ILC function and numbers during HIV and pathogenic SIV infections, most notably ILC3 in the gastrointestinal tract, which leads to disruption of the mucosal barrier and dysregulation of the local immune system. A better understanding of the direct or indirect mechanisms of loss and dysfunction will be critical to immunotherapeutics aimed at restoring these cells. Herein, we review the current literature on ILC with a particular emphasis on ILC3 and their role(s) in mucosal immunology and the significance of disrupting the ILC niche during HIV and SIV infections. [ABSTRACT FROM AUTHOR]

Natural killer cells provide an important early defense against viral pathogens and are regulated in part by interactions between highly polymorphic killer-cell immunoglobulin-like receptors (KIRs) on NK cells and their MHC class I ligands on target cells. We previously identified MHC class I ligands for two rhesus macaque KIRs: KIR3DL01 recognizes Mamu-Bw4 molecules and KIR3DL05 recognizes Mamu-A1*002. To determine how these interactions influence NK cell responses, we infected KIR3DL01+ and KIR3DL05+ macaques with and without defined ligands for these receptors with SIVmac239, and monitored NK cell responses in peripheral blood and lymphoid tissues. NK cell responses in blood were broadly stimulated, as indicated by rapid increases in the CD16+ population during acute infection and sustained increases in the CD16+ and CD16-CD56- populations during chronic infection. Markers of proliferation (Ki-67), activation (CD69 & HLA-DR) and antiviral activity (CD107a & TNFα) were also widely expressed, but began to diverge during chronic infection, as reflected by sustained CD107a and TNFα upregulation by KIR3DL01+, but not by KIR3DL05+ NK cells. Significant increases in the frequency of KIR3DL01+ (but not KIR3DL05+) NK cells were also observed in tissues, particularly in the gut-associated lymphoid tissues, where this receptor was preferentially upregulated on CD56+ and CD16-CD56- subsets. These results reveal broad NK cell activation and dynamic changes in the phenotypic properties of NK cells in response to SIV infection, including the enrichment of KIR3DL01+ NK cells in tissues that support high levels of virus replication. [ABSTRACT FROM AUTHOR]

Mechanisms responsible for natural control of human immunodeficiency type 1 (HIV) replication in elite controllers (EC) remain incompletely defined. To determine if EC generate high quality HIV-specific IgA responses, we used Western blotting to compare the specificities and frequencies of IgA to HIV antigens in serum of gender-, age- and race-matched EC and aviremic controllers (HC) and viremic noncontrollers (HN) on highly active antiretroviral therapy (HAART). Concentrations and avidity of IgA to HIV antigens were measured using ELISA or multiplex assays. Measurements for IgG were performed in parallel. EC were found to have stronger p24- and V1V2-specific IgG responses than HN, but there were no IgG differences for EC and HC. In contrast, IgA in EC serum bound more frequently to gp160 and gag proteins than IgA in HC or HN. The avidity of anti-gp41 IgA was also greater in EC, and these subjects had stronger IgA responses to the gp41 heptad repeat region 1 (HR1), a reported target of anti-bacterial RNA polymerase antibodies that cross react with gp41. However, EC did not demonstrate greater IgA responses to E. coli RNA polymerase or to peptides containing the shared LRAI sequence, suggesting that most of their HR1-specific IgA antibodies were not induced by intestinal microbiota. In both EC and HAART recipients, the concentrations of HIV-specific IgG were greater than HIV-specific IgA, but their avidities were comparable, implying that they could compete for antigen. Exceptions were C1 peptides and V1V2 loops. IgG and IgA responses to these antigens were discordant, with IgG reacting to V1V2, and IgA reacting to C1, especially in EC. Interestingly, EC with IgG hypergammaglobulinemia had greater HIV-specific IgA and IgG responses than EC with normal total IgG levels. Heterogeneity in EC antibody responses may therefore be due to a more focused HIV-specific B cell response in some of these individuals. Overall, these data suggest that development of HIV-specific IgA responses and affinity maturation of anti-gp41 IgA antibodies occurs to a greater extent in EC than in subjects on HAART. Future studies will be required to determine if IgA antibodies in EC may contribute in control of viral replication. [ABSTRACT FROM AUTHOR]

Innate lymphocyte cells (ILCs), a novel family of innate immune cells are considered to function as key orchestrators of immune defences at mucosal surfaces and to be crucial for maintaining an intact intestinal barrier. Accordingly, first data suggest depletion of ILCs to be involved in human immunodeficiency virus (HIV)-associated damage of the intestinal mucosa and subsequent microbial translocation. However, although ILCs are preferentially localized at mucosal surfaces, only little is known regarding distribution and function of ILCs in the human gastrointestinal tract. Here, we show that in HIV(-) individuals composition and functional capacity of intestinal ILCs is compartment-specific with group 1 ILCs representing the major fraction in the upper gastrointestinal (GI) tract, whereas ILC3 are the predominant population in ileum and colon, respectively. In addition, we present first data indicating that local cytokine concentrations, especially that of IL-7, might modulate composition of gut ILCs. Distribution of intestinal ILCs was significantly altered in HIV patients, who displayed decreased frequency of total ILCs in ileum and colon owing to reduced numbers of both CD127(+)ILC1 and ILC3. Of note, frequency of colonic ILC3 was inversely correlated with serum levels of I-FABP and sCD14, surrogate markers for loss of gut barrier integrity and microbial translocation, respectively. Both expression of the IL-7 receptor CD127 on ILCs as well as mucosal IL-7 mRNA levels were decreased in HIV(+) patients, especially in those parts of the GI tract with reduced ILC frequencies, suggesting that impaired IL-7 responses of ILCs might contribute to incomplete reconstitution of ILCs under effective anti-retroviral therapy. This is the first report comparing distribution and function of ILCs along the intestinal mucosa of the entire human gastrointestinal tract in HIV(+) and HIV(-) individuals. [ABSTRACT FROM AUTHOR]

Background: In the Friend retrovirus mouse model we developed potent adenovirus-based vaccines that were designed to induce either strong Friend virus GagL85-93-specific CD8+ T cell or antibody responses, respectively. To optimize the immunization outcome we evaluated vaccination strategies using combinations of these vaccines. Results: While the vaccines on their own confer strong protection from a subsequent Friend virus challenge, the simple combination of the vaccines for the establishment of an optimized immunization protocol did not result in a further improvement of vaccine effectivity. We demonstrate that the co-immunization with GagL85-93/leader-gag encoding vectors together with envelope-encoding vectors abrogates the induction of GagL85-93-specific CD8+ T cells, and in successive immunization protocols the immunization with the GagL85-93/leader-gag encoding vector had to precede the immunization with an envelope encoding vector for the efficient induction of GagL85-93-specific CD8+ T cells. Importantly, the antibody response to envelope was in fact enhanced when the mice were adenovirusexperienced from a prior immunization, highlighting the expedience of this approach. Conclusions: To circumvent the immunosuppressive effect of envelope on immune responses to simultaneously or subsequently administered immunogens, we developed a two immunizations-based vaccination protocol that induces strong immune responses and confers robust protection of highly Friend virus-susceptible mice from a lethal Friend virus challenge. [ABSTRACT FROM AUTHOR]

Background: A vast diversity of microbes colonizes in the human gastrointestinal tract, referred to intestinal microbiota. Microbiota and products thereof are indispensable for shaping the development and function of host innate immune system, thereby exerting multifaceted impacts in gut health. Methods: This paper reviews the effects on immunity of gut microbe-derived nucleic acids, and gut microbial metabolites, as well as the involvement of commensals in the gut homeostasis. We focus on the recent findings with an intention to illuminate the mechanisms by which the microbiota and products thereof are interacting with host immunity, as well as to scrutinize imbalanced gut microbiota (dysbiosis) which lead to autoimmune disorders including inflammatory bowel disease (IBD), Type 1 diabetes (T1D) and systemic immune syndromes such as rheumatoid arthritis (RA). Results: In addition to their well-recognized benefits in the gut such as occupation of ecological niches and competition with pathogens, commensal bacteria have been shown to strengthen the gut barrier and to exert immunomodulatory actions within the gut and beyond. It has been realized that impaired intestinal microbiota not only contribute to gut diseases but also are inextricably linked to metabolic disorders and even brain dysfunction. Conclusions: A better understanding of the mutual interactions of the microbiota and host immune system, would shed light on our endeavors of disease prevention and broaden the path to our discovery of immune intervention targets for disease treatment. [ABSTRACT FROM AUTHOR]

In order to evaluate the role of persisting virus replication during occult phase immunisation in the live attenuated SIV vaccine model, a novel SIVmac239Δnef variant (SIVrtTA) genetically engineered to replicate in the presence of doxycycline was evaluated for its ability to protect against wild-type SIVmac239. Indian rhesus macaques were vaccinated either with SIVrtTA or with SIVmac239Δnef. Doxycycline was withdrawn from 4 of 8 SIVrtTA vaccinates before challenge with wild-type virus. Unvaccinated challenge controls exhibited ~107 peak plasma viral RNA copies/ml persisting beyond the acute phase. Six vaccinates, four SIVmac239Δnef and two SIVrtTA vaccinates exhibited complete protection, defined by lack of wild-type viraemia post-challenge and virus-specific PCR analysis of tissues recovered post-mortem, whereas six SIVrtTA vaccinates were protected from high levels of viraemia. Critically, the complete protection in two SIVrtTA vaccinates was associated with enhanced SIVrtTA replication in the immediate post-acute vaccination period but was independent of doxycycline status at the time of challenge. Mutations were identified in the LTR promoter region and rtTA gene that do not affect doxycycline-control but were associated with enhanced post-acute phase replication in protected vaccinates. High frequencies of total circulating CD8+T effector memory cells and a higher total frequency of SIV-specific CD8+ mono and polyfunctional T cells on the day of wild-type challenge were associated with complete protection but these parameters were not predictive of outcome when assessed 130 days after challenge. Moreover, challenge virus-specific Nef CD8+ polyfunctional T cell responses and antigen were detected in tissues post mortem in completely-protected macaques indicating post-challenge control of infection. Within the parameters of the study design, on-going occult-phase replication may not be absolutely required for protective immunity. [ABSTRACT FROM AUTHOR]

This panel was developed to measure the functional capability of natural killer (NK) cell subsets in rhesus macaques ( Macaca mulatta). It includes markers to determine the frequency of cytokine secreting and cytotoxic NK cell subpopulations in peripheral blood mononuclear cell (PBMC) samples stimulated in vitro with human 721.221 cells. NK cell subsets were defined by the expression of killer cell immunoglobulin-like receptors (KIRs) Mamu-KIR3DL01 and Mamu-KIR3DL05, and differentiation antigens CD16 and CD56. The panel can be used to assess the functional capability of NK cells in a range of normal and pathologic conditions of captive bred rhesus macaques of Indian origin. © 2016 International Society for Advancement of Cytometry [ABSTRACT FROM AUTHOR]

NK cells are crucial components of the innate immune system due to their capacity to exert rapid cytotoxic and immunomodulatory function in the absence of prior sensitization. NK cells can become activated by exposure to target cells and/or by cytokines produced by antigen-presenting cells. In this study, we examined the effects of a simian immunodeficiency virus (SIV) vaccine regimen and subsequent SIV infection on the cytotoxic and immunomodulatory functions of circulatory NK cells. While vaccination did not significantly impact the capacity of NK cells to kill MHC-devoid 721.221 target cells, SIV-infection led to a significant decrease in target cell killing. NK cells from uninfected macaques were responsive to a low dose (5 ng/ml) of IL-15 pre-activation, leading to significant increases in their cytotoxic potential, however, NK cells from SIV-infected macaques required a higher dose (50 ng/ml) of IL-15 pre-activation in order to significantly increase their cytotoxic potential. By contrast, no differences were observed in the capacity of NK cells from vaccinated and SIV-infected macaques to respond to IL-12 and IL-18. Similarly, NK cells both before and after infection exhibited equivalent responses to Fc-mediated activation. Collectively, our results show that early SIV-infection impairs the natural cytotoxic capacity of circulatory NK cells without affecting Fc-mediated or cytokine-producing function. [ABSTRACT FROM AUTHOR]

In humans, CD16 and CD56 are used to identify functionally distinct natural killer (NK) subsets. Due to ubiquitous CD56 expression, this marker cannot be used to distinguish between NK cell subsets in chimpanzees. Therefore, functional analysis of distinct NK subsets during hepatitis C virus (HCV) infection has never been performed in these animals. In the present study an alternative strategy was used to identify four distinct NK subsets on the basis of the expression of CD16 and CD94. The expression of activating and inhibiting surface receptors showed that these subsets resemble human NK subsets. CD107 expression was used to determine degranulation of the different subsets in naive and HCV-infected chimpanzees. In HCV-infected chimpanzees increased spontaneous cytotoxicity was observed in CD94high/dimCD16pos and CD94lowCD16pos subsets. By contrast, increased natural cytotoxicity receptor (NCR)- mediated degranulation after NKp30 and NKp44 triggering was demonstrated in the CD94dimCD16neg subset. Our findings suggest that spontaneous and NCR-mediated cytotoxicity are effector functions of distinct NK subsets in HCV-infected chimpanzees. [ABSTRACT FROM AUTHOR]

Plasmacytoid dendritic cells (pDC) are innate immune cells that sense viral nucleic acids through endosomal Toll-like receptor (TLR) 7/9 to produce type I interferon (IFN) and to differentiate into potent antigen presenting cells (APC). Engagement of TLR7/9 in early endosomes appears to trigger the IRF7 pathway for IFN production whereas engagement in lysosomes seems to trigger the NF-κB pathway for maturation into APC. We showed previously that HIV-1 (HIV) localizes predominantly to early endosomes, not lysosomes, and mainly stimulate IRF7 rather than NF-κB signaling pathways in pDC. This divergent signaling may contribute to disease progression through production of pro-apoptotic and pro-inflammatory IFN and inadequate maturation of pDCs. We now demonstrate that HIV virions may be re-directed to lysosomes for NF-κB signaling by either pseudotyping HIV with influenza hemagglutinin envelope or modification of CD4 mediated-intracellular trafficking. These data suggest that HIV envelope-CD4 receptor interactions drive pDC activation toward an immature IFN producing phenotype rather than differentiation into a mature dendritic cell phenotype. [ABSTRACT FROM AUTHOR]

Disruption of the mucosal epithelium during lentivirus infections permits translocation of microbial products into circulation, causing immune activation and driving disease. Although the liver directly filters blood from the intestine and is the first line of defense against gut-derived antigens, the effects of microbial products on the liver are unclear. In livers of normal macaques, minute levels of bacterial products were detectable, but increased 20-fold in simian immunodeficiency virus (SIV)-infected animals. Increased microbial products in the liver induced production of the chemoattractant CXCL16 by myeloid dendritic cells (mDCs), causing subsequent recruitment of hypercytotoxic natural killer (NK) cells expressing the CXCL16 receptor, CXCR6. Microbial accumulation, mDC activation, and cytotoxic NK cell frequencies were significantly correlated with markers of liver damage, and SIV-infected animals consistently had evidence of hepatitis and fibrosis. Collectively, these data indicate that SIV-associated accumulation of microbial products in the liver initiates a cascade of innate immune activation, resulting in liver damage. [ABSTRACT FROM AUTHOR]

The female reproductive tract (FRT) is a major site for human immunodeficiency virus (HIV) infection. There currently exists a poor understanding of how the innate immune system is activated upon HIV transmission and how this activation may affect systemic spread of HIV from the FRT. However, multiple mechanisms for how HIV is sensed have been deciphered using model systems with cell lines and peripheral blood-derived cells. The aim of this review is to summarize recent progress in the field of HIV innate immune sensing and place this in the context of the FRT. Because HIV is somewhat unique as an STD that thrives under inflammatory conditions, the response of cells upon sensing HIV gene products can either promote or limit HIV infection depending on the context. Future studies should include investigations into how FRT-derived primary cells sense and respond to HIV to confirm conclusions drawn from non-mucosal cells. Understanding how cells of the FRT participate in and effect innate immune sensing of HIV will provide a clearer picture of what parameters during the early stages of HIV exposure determine transmission success. Such knowledge could pave the way for novel approaches for preventing HIV acquisition in women. [ABSTRACT FROM AUTHOR]

A correction to the article "CD8 T Cell Response Maturation Defined by Anentropic Specificity and Repertoire Depth Correlates with SIVΔnef-induced Protection," that appeared in the 2015 issue is presented.

Plasmacytoid dendritic cells (pDCs) in the periphery of subjects with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) decrease over time, and the fate of these cells has been the subject of ongoing investigation. Previous studies using animal models as well as studies with humans suggest that these cells may redistribute to the gut. Other studies using animal models propose that the periphery pDCs are depleted and gut is repopulated with naive pDCs from the bone marrow. In the present study, we utilized immunohistochemistry to survey duodenum biopsies of subjects with HIV/AIDS and controls. We observed that subjects with HIV/AIDS had increased infiltration of Ki-67+/CD303+ pDCs, a phenotype consistent with bone marrow- derived pre-pDCs. In contrast, Ki-67+/CD303+ pDCs were not observed in control biopsies. We additionally observed that gut-associated pDCs in HIV/AIDS cases upregulate the proapoptotic enzyme granzyme B; however, no granzyme B was observed in the pDCs of control biopsies. Our data are consistent with reports in animal models that suggest periphery pDCs are depleted by exhaustion and that naive pDCs egress from the bone marrow and ultimately infiltrate the gut mucosa. Additionally, our observation of granzyme B upregulation in naive pDCs may identify a contributing factor to the gut pathology associated with HIV infection. [ABSTRACT FROM AUTHOR]

HIV infection induces immune alterations, mainly in gut mucosa, where the main target cells reside. However, the evolution of the infection is variable among infected individuals, as evidenced by HIV controllers who exhibit low or undetectable viral load in the absence of treatment. The aim of this study was to evaluate the frequency, phenotype and activity of T and NK cells in peripheral blood and gut mucosa in a cohort of Colombian HIV controllers. Blood and gut biopsies were included. The frequency and the activation status of T and NK cells were performed by flow cytometry. In addition, Gag-stimulated CD8+ T-cells and cytokine-stimulated NK cells were tested for cytotoxic activity. Finally, microbial translocation was measured by plasma lipopolysaccharide quantification. Compared with HIV-progressors, HIV controllers exhibited higher frequency of CD4+ T and NK cells, and lower expression of activation molecules in blood and mucosal immune cells, as well as lower microbial translocation. An increased production of molecules associated with cytotoxic activity of CD8+ T-cells in blood and mucosa and a higher percentage of polyfunctional CD8+ T cells in blood were also observed in HIV controllers. In addition, an increased activity of NK cells was observed in blood. These findings suggest that HIV controllers have a potent immune response, mainly mediated by cytotoxic cells that control HIV replication, which contribute to reducing alterations at the gut mucosa. [ABSTRACT FROM AUTHOR]

Natural killer ( NK) cells are essential components of the immune system, and due to their rapid response potential, can have a great impact during early anti-viral immune responses. We have previously shown that interleukin-2-dependent NK and CD4+ T-cell co-operative immune responses exist in long-term simian immunodeficiency virus ( SIV) -infected controlling macaques and can be rescued in SIV-infected non-controlling macaques by a short course of antiretroviral therapy ( ART). Given that co-operative responses may play an important role in disease prevention and therapeutic treatment, in the present study we sought to determine if these responses can be enhanced in chronically SIV-infected macaques by vaccination with a single-dose of envelope protein given during ART. To this end, we treated 14 chronically SIV-infected macaques with ART for 11 weeks and gave 10 of these macaques a single intramuscular dose of SIV gp120 at week 9 of treatment. ART significantly decreased plasma and mucosal viral loads, increased the numbers of circulating CD4+ T cells in all macaques, and increased T-cell-dependent envelope- and gag-specific interferon- γ and tumour necrosis factor- α production by circulatory CD56+ NK cells. The therapeutic envelope immunization resulted in higher envelope-specific responses compared with those in macaques that received ART only. Functional T-cell responses restored by ART and therapeutic Env immunization were correlated with transiently reduced plasma viraemia levels following ART release. Collectively our results indicate that SIV-specific T-cell-dependent NK cell responses can be efficiently rescued by ART in chronically SIV-infected macaques and that therapeutic immunization may be beneficial in previously vaccinated individuals. [ABSTRACT FROM AUTHOR]

Since the demonstration of a cure of an HIV+ patient with an allogeneic stem cell transplant using naturally HIV-resistant cells, significant interest in creating similar autologous products has fueled the development of a variety of 'cell engineering' approaches to stem cell therapy for HIV. Among the more well-studied strategies is the inhibition of viral entry through disruption of expression of viral co-receptors or through competitive inhibitors of viral fusion with the cell membrane. Preclinical evaluation of these approaches often starts in vitro but ultimately is tested in animal models prior to clinical implementation. In this review, we trace the development of several key approaches (meganucleases, short hairpin RNA (shRNA), and fusion inhibitors) to modification of hematopoietic stem cells designed to impart resistance to HIV to their T-cell and monocytic progeny. The basic evolution of technologies through in vitro and in vivo testing is discussed as well as the pros and cons of each approach and how the addition of postentry inhibitors may enhance the overall antiviral efficacy of these approaches. [ABSTRACT FROM AUTHOR]

Despite over 30 years of research, the contribution of type I interferons (IFN-Is) to both the control of HIV replication and initiation of immunologic damage remains debated. In acute infection, IFN-Is, likely from plasmacytoid dendritic cells (pDCs), activate NK cells and upregulate restriction factors targeting virtually the entire HIV life cycle. In chronic infection, IFN-Is may also contribute to CD4 T cell loss and immune exhaustion. pDCs subsequently infiltrate lymphoid and mucosal tissues, and their circulating populations wane in chronic infection; IFN-I may be produced by other cells. Data from nonhuman primates indicate prompt IFN-I signaling is critical in acute infection. Whereas some studies showed IFN-I administration without combination antiretroviral therapy (cART) is beneficial, others suggest that stimulating or blocking IFN-I signaling in chronic ART-suppressed HIV infection has had positive results. Here, we describe the history of HIV and IFN-I, IFN-I's sources, IFN-I's effects on HIV control and host defense, and recent interventional studies in SIV and HIV infection. [ABSTRACT FROM AUTHOR]

HIV/SIV infections break down the integrity of the gastrointestinal mucosa and lead to chronic immune activation and associated disease progression. Innate lymphoid cells (ILCs), distinguishable by high expression of NKp44 and RORγt, play key roles in mucosal defense and homeostasis, but are depleted from gastrointestinal (GI) tract large bowel during chronic SIV infection. However, less is known about the kinetics of ILC loss, or if it occurs systemically. In acute SIV infection, we found a massive, up to 8-fold, loss of NKp44+ILCs in all mucosae as early as day 6 post-infection, which was sustained through chronic disease. Interestingly, no loss of ILCs was observed in mucosa-draining lymph nodes. In contrast, classical NK cells were not depleted either from gut or draining lymph nodes. Both ILCs and NK cells exhibited significantly increased levels of apoptosis as measured by increased Annexin-V expression, but while classical NK cells also showed increased proliferation, ILCs did not. Interestingly, ILCs, which are normally noncytolytic, dramatically upregulated cytotoxic functions in acute and chronic infection and acquired a polyfunctional phenotype secreting IFN-γ, MIP1-β, and TNF-α, but decreased production of the prototypical cytokine, IL-17. Classical NK cells had less dramatic functional change, but upregulated perforin expression and increased cytotoxic potential. Finally, we show that numerical and functional loss of ILCs was due to increased apoptosis and ROR γt suppression induced by inflammatory cytokines in the gut milieu. Herein we demonstrate the first evidence for acute, systemic, and permanent loss of mucosal ILCs during SIV infection associated with reduction of IL-17. The massive reduction of ILCs involves apoptosis without compensatory de novo development/proliferation, but the full mechanism of depletion and the impact of functional change so early in infection remain unclear. [ABSTRACT FROM AUTHOR]

Killer cell immunoglobulin-like receptors (KIR) regulate the activity of natural killer (NK) cells and have been shown to be associated with susceptibility to a number of human infectious diseases. Here, we analyzed NK cell function and genetic associations in a cohort of 52 rhesus macaques experimentally infected with SIVmac and subsequently stratified into high viral load (HVL) and low viral load (LVL) plasma viral loads at set point. This stratification coincided with fast (HVL) and slow (LVL) disease progression indicated by the disease course and critical clinical parameters including CD4CT cell counts. HVL animals revealed sustained proliferation of NK cells but distinct loss of peripheral blood NK cell numbers and lytic function. Genetic analyses revealed that KIR genes 3DL05, 3DS05, and 3DL10 as well as 3DSW08, 3DLW03, and 3DSW09 are correlated, most likely due to underlying haplotypes. SIV-infection outcome associated with presence of transcripts for two inhibitory KIR genes (KIR3DL02, KIR3DL10) and three activating KIR genes (KIR3DSW08, KIR3DS02, KIR3DS05). Presence of KIR3DL02 and KIR3DSW08 was associated with LVL outcome, whereas presence of KIR3DS02 was associated with HVL outcome. Furthermore, we identified epistasis between KIR and MHC class I alleles as the transcript presence of the correlated genes KIR3DL05, KIR3DS05, and KIR3DL10 increased HVL risk when Mamu-B*012 transcripts were also present or when Mamu-A1*001 transcripts were absent. These genetic associations were mirrored by changes in the numbers, the level of proliferation, and lytic capabilities of NK cells as well as overall survival time and gastro-intestinal tissue viral load. [ABSTRACT FROM AUTHOR]

Background To increase the immunosurveillance in HIV infection, we used retroviral vectors expressing CD4-chimeric antigen receptors ( CARs) to genetically modify autologous T cells and redirect CTL toward HIV. The CD4 extracellular domain targets envelope and the intracellular signaling domains activate T cells. The maC46 fusion inhibitor binds HIV and blocks viral replication. Methods We stimulated rhesus PBMCs with antibodies to CD3/CD28 and cotransduced T cells with CD4- CAR and maC46 vectors. CD4- CAR-transduced T cells were added to Env+ 293T cells at E:T of 1:1. Killing of target cells was measured as reduced impedance. Results We observed gene expression in 60-70% of rhesus CD3+ CD8+ T cells with the individual vectors and in 35% of the cells with both vectors. CD4- CAR-transduced populations specifically killed Env+ cells. Conclusions In these studies, we showed that designer T cells were redirected to kill Env+ cells. Control of viremia without HAART would revolutionize treatment for HIV patients. [ABSTRACT FROM AUTHOR]

HIV-1 infected viremic controllers maintain durable viral suppression below 2000 copies viral RNA/ml without anti-retroviral therapy (ART), and the immunological factor(s) associated with host control in presence of low but detectable viral replication are of considerable interest. Here, we utilized a multivariable analysis to identify which innate and adaptive immune parameters best correlated with viral control utilizing a cohort of viremic controllers (median 704 viral RNA/ml) and non-controllers (median 21,932 viral RNA/ml) that were matched for similar CD4+ T cell counts in the absence of ART. We observed that HIV-1 Gag-specific CD8+ T cell responses were preferentially targeted over Pol-specific responses in viremic controllers (p = 0.0137), while Pol-specific responses were positively associated with viral load (rho = 0.7753, p = 0.0001, n = 23). Viremic controllers exhibited significantly higher NK and plasmacytoid dendritic cells (pDC) frequency as well as retained expression of the NK CD16 receptor and strong target cell-induced NK cell IFN-gamma production compared to non-controllers (p<0.05). Despite differences in innate and adaptive immune function however, both viremic controllers (p<0.05) and non-controller subjects (p<0.001) exhibited significantly increased CD8+ T cell activation and spontaneous NK cell degranulation compared to uninfected donors. Overall, we identified that a combination of innate (pDC frequency) and adaptive (Pol-specific CD8+ T cell responses) immune parameters best predicted viral load (R2 = 0.5864, p = 0.0021, n = 17) by a multivariable analysis. Together, this data indicates that preferential Gag-specific over Pol-specific CD8+ T cell responses along with a retention of functional innate subsets best predict host control over viral replication in HIV-1 infected viremic controllers compared to chronically-infected non-controllers. [ABSTRACT FROM AUTHOR]

Chronic immune activation (IA) is considered as the driving force of CD4+ T cell depletion and AIDS. Fundamental clues in the mechanisms that regulate IA could lie in natural hosts of SIV, such as African green monkeys (AGMs). Here we investigated the role of innate immune cells and IFN-α in the control of IA in AGMs. AGMs displayed significant NK cell activation upon SIVagm infection, which was correlated with the levels of IFN-α. Moreover, we detected cytotoxic NK cells in lymph nodes during the early acute phase of SIVagm infection. Both plasmacytoid and myeloid dendritic cell (pDC and mDC) homing receptors were increased, but the maturation of mDCs, in particular of CD16+ mDCs, was more important than that of pDCs. Monitoring of 15 cytokines showed that those, which are known to be increased early in HIV-1/SIVmac pathogenic infections, such as IL-15, IFN-α, MCP-1 and CXCL10/IP-10, were significantly increased in AGMs as well. In contrast, cytokines generally induced in the later stage of acute pathogenic infection, such as IL-6, IL-18 and TNF-α, were less or not increased, suggesting an early control of IA. We then treated AGMs daily with high doses of IFN-α from day 9 to 24 post-infection. No impact was observed on the activation or maturation profiles of mDCs, pDCs and NK cells. There was also no major difference in T cell activation or interferon-stimulated gene (ISG) expression profiles and no sign of disease progression. Thus, even after administration of high levels of IFN-α during acute infection, AGMs were still able to control IA, showing that IA control is independent of IFN-α levels. This suggests that the sustained ISG expression and IA in HIV/SIVmac infections involves non-IFN-α products. [ABSTRACT FROM AUTHOR]

HIV research has made rapid progress and led to remarkable achievements in recent decades, the most important of which are combination antiretroviral therapies (cART). However, in the absence of a vaccine, the pandemic continues, and additional strategies are needed. The 'towards an HIV cure' initiative aims to eradicate HIV or at least bring about a lasting remission of infection during which the host can control viral replication in the absence of cART. Cases of spontaneous and treatment-induced control of infection offer substantial hope. Here, we describe the scientific knowledge that is lacking, and the priorities that have been established for research into a cure. We discuss in detail the immunological lessons that can be learned by studying natural human and animal models of protection and spontaneous control of viraemia or of disease progression. In particular, we describe the insights we have gained into the immune mechanisms of virus control, the impact of early virus-host interactions and why chronic inflammation, a hallmark of HIV infection, is an obstacle to a cure. Finally, we enumerate current interventions aimed towards improving the host immune response [ABSTRACT FROM AUTHOR]

Gene therapy represents an alternative and promising anti-HIV modality to highly active antiretroviral therapy. It involves the introduction of a protective gene into a cell, thereby conferring protection against HIV. While clinical trials to date have delivered gene therapy to CD4+T cells or to CD34+ hematopoietic stem cells (HSC), the relative benefits of each of these two cellular targets have not been conclusively determined. In the present analysis, we investigated the relative merits of delivering a dual construct (CCR5 entry inhibitor + C46 fusion inhibitor) to either CD4+T cells or to CD34+ HSC. Using mathematical modelling, we determined the impact of each scenario in terms of total CD4+T cell counts over a 10 year period, and also in terms of inhibition of CCR5 and CXCR4 tropic virus. Our modelling determined that therapy delivery to CD34+ HSC generally resulted in better outcomes than delivery to CD4+T cells. An early one-off therapy delivery to CD34+ HSC, assuming that 20% of CD34+ HSC in the bone marrow were gene-modified (G+), resulted in total CD4+T cell counts ≥180 cells/ µL in peripheral blood after 10 years. If the uninfected G+ CD4+T cells (in addition to exhibiting lower likelihood of becoming productively infected) also exhibited reduced levels of bystander apoptosis (92.5% reduction) over non gene-modified (G-) CD4+T cells, then total CD4+T cell counts of ≥350 cells/ µL were observed after 10 years, even if initially only 10% of CD34+ HSC in the bone marrow received the protective gene. Taken together our results indicate that: 1.) therapy delivery to CD34+ HSC will result in better outcomes than delivery to CD4+T cells, and 2.) a greater impact of gene therapy will be observed if G+ CD4+T cells exhibit reduced levels of bystander apoptosis over G- CD4+T cells. [ABSTRACT FROM AUTHOR]

Since the discovery that new genetic material could be transferred into human cells resulting in induced expression of genes and proteins, clinicians and scientists have been working to harness the technology for clinical outcomes. This article provides a summary of the current status of developments within the broad discipline of clinical gene therapy. In pursuing the treatment of diverse clinical conditions, a wide variety of therapeutics, each tailor-made, may be required. Gene therapy offers the possibility of accurately and specifically targeting particular genetic abnormalities through gene correction, addition or replacement. It represents a compelling idea that adds a new dimension to our portfolio of credible therapeutic choices. [ABSTRACT FROM AUTHOR]

The studies reported herein are the first to document the effect of the in vivo administration of a JAK3 inhibitor for defining the potential role of NK cells during acute SIV infection of a group of 15 rhesus macaques (RM). An additional group of 16 MHC/KIR typed RM was included as controls. The previously optimized in vivo dose regimen (20 mg/kg daily for 35 days) led to a marked depletion of each of the major NK cell subsets both in the blood and gastro-intestinal tissues (GIT) during acute infection. While such depletion had no detectable effects on plasma viral loads during acute infection, there was a significant sustained increase in plasma viral loads during chronic infection. While the potential mechanisms that lead to such increased plasma viral loads during chronic infection remain unclear, several correlates were documented. Thus, during acute infection, the administration of the JAK3 inhibitor besides depleting all NK cell subsets also decreased some CD8+ T cells and inhibited the mobilization of the plasmacytoid dendritic cells in the blood and their localization to the GIT. Of interest is the finding that the administration of the JAK3 inhibitor during acute infection also resulted in the sustained maintenance during chronic infection of a high number of naïve and central memory CD4+ T cells, increases in B cells in the blood, but decreases in the frequencies and function of NKG2a+ NK cells within the GIT and blood, respectively. These data identify a unique role for JAK3 inhibitor sensitive cells, that includes NK cells during acute infection that in concert lead to high viral loads in SIV infected RM during chronic infection without affecting detectable changes in antiviral humoral/cellular responses. Identifying the precise mechanisms by which JAK3 sensitive cells exert their influence is critical with important implications for vaccine design against lentiviruses. [ABSTRACT FROM AUTHOR]

The emerging paradigm that MSCs are immune privileged has fostered the use of “off-the-shelf” allogeneic MSC-based therapies in human clinical trials. However, this approach ignores studies in experimental animals wherein transplantation of MSCs across MHC boundaries elicits measurable allo-immune responses. To determine if MSCs are hypo-immunogeneic, we characterized the immune response in rhesus macaques following intracranial administration of allogeneic vs. autologous MSCs. This analysis revealed unambiguous evidence of productive allo-recognition based on expansion of NK, B and T cell subsets in peripheral blood and detection of allo-specific antibodies in animals administered allogeneic but not autologous MSCs. Moreover, the degree of MHC class I and II mismatch between the MSC donor and recipient significantly influenced the magnitude and nature of the allo-immune response. Consistent with these findings, real-time PCR analysis of brain tissue from female recipients administered varying doses of male, allogeneic MSCs revealed a significant inverse correlation between MSC engraftment levels and cell dose. Changes in post-transplant neutrophil and lymphocyte counts also correlated with dose and were predictive of overall MSC engraftment levels. However, secondary antigen challenge failed to elicit a measurable immune response in allogeneic recipients. Finally, extensive behavior testing of animals revealed no main effect of cell dose on motor skills, social development, or temperament. Collectively, these data indicate that allogeneic MSCs are weakly immunogenic when transplanted across MHC boundaries in rhesus macaques and this negatively impacts durable engraftment levels. Therefore the use of unrelated donor MSCs should be carefully evaluated in human patients. [ABSTRACT FROM AUTHOR]

IFN-I production is a characteristic of HIV/SIV primary infections. However, acute IFN-I plasma concentrations rapidly decline thereafter. Plasmacytoid dendritic cells (pDC) are key players in this production but primary infection is associated with decreased responsiveness of pDC to TLR 7 and 9 triggering. IFNα production during primary SIV infection contrasts with increased pDC death, renewal and dysfunction. We investigated the contribution of pDC dynamics to both acute IFNα production and the rapid return of IFNα concentrations to pre-infection levels during acute-to-chronic transition. Nine cynomolgus macaques were infected with SIVmac251 and IFNα-producing cells were quantified and characterized. The plasma IFN-I peak was temporally associated with the presence of IFNα+ pDC in tissues but IFN-I production was not detectable during the acute-to-chronic transition despite persistent immune activation. No IFNα+ cells other than pDC were detected by intracellular staining. Blood-pDC and peripheral lymph node-pDC both lost IFNα− production ability in parallel. In blood, this phenomenon correlated with an increase in the counts of Ki67+-pDC precursors with no IFNα production ability. In tissues, it was associated with increase of both activated pDC and KI67+-pDC precursors, none of these being IFNα+in vivo. Our findings also indicate that activation/death-driven pDC renewal rapidly blunts acute IFNα production in vivo: pDC sub-populations with no IFNα-production ability rapidly increase and shrinkage of IFNα production thus involves both early pDC exhaustion, and increase of pDC precursors. [ABSTRACT FROM AUTHOR]

Background There is significant debate about whether the gut plays a major role in viral replication and pathology in HIV infection. Here we aimed to estimate the contribution of the gut to the total virus observed in plasma, by comparing the frequency of different viral mutants in plasma and gut in SIV infection. Results We found that the maximum contribution of gut to plasma viral load estimated from rectal biopsy at day 28 post-infection had a median of 10%. The estimated values for individual animals ranged from nearly 100% to <3% in 4/14 animals. Importantly, these are maximum estimates, so that a value of 90%, for example, means that the real contribution may be anything between 0 and 90%, just not higher than 90%. We also studied the contribution of gut at the peak of plasma viral load (day 14). However, since there was very little escape in most animals at this time point, we could only estimate the maximal contribution of gut in 4 animals, in two of which it was <15%. Conclusions The role of the gut in HIV is a controversial area, with many suggesting that it plays a dominant role in driving early infection. Our analysis suggests that, at least by day 28 postinfection, the gut is not contributing greatly to the plasma viral load. [ABSTRACT FROM AUTHOR]

Despite extensive use of nonhuman primates as models for infectious diseases and reproductive biology, imprecise phenotypic and functional definitions exist for natural killer (NK) cells. This deficit is particularly significant in the burgeoning use of small, less expensive New World primate species. Using polychromatic flow cytometry, we identified peripheral blood NK cells as CD3-negative and expressing a cluster of cell surface molecules characteristic of NK cells (i.e., NKG2A, NKp46, NKp30) in three New World primate species – common marmosets, cotton-top tamarins, and squirrel monkeys. We then assessed subset distribution using the classical NK markers, CD56 and CD16. In all species, similar to Old World primates, only a minor subset of NK cells was CD56+, and the dominant subset was CD56–CD16+. Interestingly, CD56+ NK cells were primarily cytokine-secreting cells, whereas CD56–CD16+ NK cells expressed significantly greater levels of intracellular perforin, suggesting these cells might have greater potential for cytotoxicity. New World primate species, like Old World primates, also had a minor CD56–CD16– NK cell subset that has no obvious counterpart in humans. Herein we present phenotypic profiles of New World primate NK cell subpopulations that are generally analogous to those found in humans. This conservation among species should support the further use of these species for biomedical research. [ABSTRACT FROM AUTHOR]

Background HIV and SIV infections induce NK cell dysfunction and hematopoietic defects in the bone marrow, but the effects of infection on bone marrow NK cell development and function are unknown. Methods Bone marrow NK cells were analyzed from both naïve and chronically SIV-infected rhesus macaques using polychromatic flow cytometry. Results NK cell frequencies were reduced in infected compared with naïve animals, associated with increased apoptosis. Bone marrow NK cells from SIV-infected macaques upregulated perforin expression, suggesting increased cytotoxicity, and shifted toward a more mature CD16+ NK cell subpopulation phenotype. Unexpectedly, expression of the trafficking markers α4β7, CCR7, and CD62L was unchanged on bone marrow NK cells during SIV infection. Conclusion These data demonstrate that during SIV infection, bone marrow NK cells are reduced in number, but upregulate cytotoxic functions. Furthermore, our data suggest acquired cytotoxicity and loss may be due to in situ NK cell differentiation and not emigration. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the systemic effects of chronic simian immunodeficiency virus ( SIV) infection on plasmacytoid dendritic cells (p DCs). p DCs play a critical role in antiviral immunity, but current data are conflicting on whether p DCs inhibit HIV/ SIV replication, or, alternatively, contribute to chronic immune activation and disease. Furthermore, previous p DC studies have been complicated by incomplete descriptions of generalized depletion during HIV/ SIV infection, and the effects of infection on p DCs outside peripheral blood remain unclear. In scheduled-sacrifice studies of naive and chronically SIV-infected rhesus macaques we evaluated the distribution and functionality of p DCs in multiple tissues using surface and intracellular polychromatic flow cytometry. As previously observed, p DCs were reduced in peripheral blood and spleens, but were also depleted in non-lymphoid organs such as the liver. Interestingly, pDCs accumulated up to fourfold in jejunum, colon and gut-draining lymph nodes, but not in peripheral lymph nodes. Most unexpectedly, SIV infection induced a multi-functional interferon-α, tumour necrosis factor-α, and macrophage inflammatory protein-1β cytokine secretion phenotype, whereas in normal animals these were generally distinct and separate functions. Herein we show a systemic redistribution of p DCs to gut tissues and gut-draining lymph nodes during chronic SIV infection, coupled to a novel multi-functional cytokine-producing phenotype. While p DC accumulation in the mucosa could aid in virus control, over-production of cytokines from these cells could also contribute to the increased immune activation in the gut mucosa commonly associated with progressive lentivirus infections. [ABSTRACT FROM AUTHOR]

We assessed the role of myeloid dendritic cells (mDCs) in the outcome of SIV infection by comparing and contrasting their frequency, mobilization, phenotype, cytokine production and apoptosis in pathogenic (pigtailed macaques, PTMs), nonpathogenic (African green monkeys, AGMs) and controlled (rhesus macaques, RMs) SIVagmSab infection. Through the identification of recently replicating cells, we demonstrated that mDC mobilization from the bone marrow occurred in all species postinfection, being most prominent in RMs. Circulating mDCs were depleted with disease progression in PTMs, recovered to baseline values after the viral peak in AGMs, and significantly increased at the time of virus control in RMs. Rapid disease progression in PTMs was associated with low baseline levels and incomplete recovery of circulating mDCs during chronic infection. mDC recruitment to the intestine occurred in all pathogenic scenarios, but loss of mucosal mDCs was associated only with progressive infection. Sustained mDC immune activation occurred throughout infection in PTMs and was associated with increased bystander apoptosis in blood and intestine. Conversely, mDC activation occurred only during acute infection in nonprogressive and controlled infections. Postinfection, circulating mDCs rapidly became unresponsive to TLR7/8 stimulation in all species. Yet, stimulation with LPS, a bacterial product translocated in circulation only in SIV-infected PTMs, induced mDC hyperactivation, apoptosis and excessive production of proinflammatory cytokines. After infection, spontaneous production of proinflammatory cytokines by mucosal mDCs increased only in progressor PTMs. We thus propose that mDCs promote tolerance to SIV in the biological systems that lack intestinal dysfunction. In progressive infections, mDC loss and excessive activation of residual mDCs by SIV and additional stimuli, such as translocated microbial products, enhance generalized immune activation and inflammation. Our results thus provide a mechanistic basis for the role of mDCs in the pathogenesis of AIDS and elucidate the causes of mDC loss during progressive HIV/SIV infections. [ABSTRACT FROM AUTHOR]

Stable integration of HIV proviral DNA into host cell chromosomes, a hallmark and essential feature of the retroviral life cycle, establishes the infection permanently. Current antiretroviral combination drug therapy cannot cure HIV infection. However, expressing an engineered HIV-1 long terminal repeat (LTR) site-specific recombinase (Tre), shown to excise integrated proviral DNA in vitro, may provide a novel and highly promising antiviral strategy. We report here the conditional expression of Tre-recombinase from an advanced lentiviral self-inactivation (SIN) vector in HIV-infected cells. We demonstrate faithful transgene expression, resulting in accurate provirus excision in the absence of cytopathic effects. Moreover, pronounced Tre-mediated antiviral effects are demonstrated in vivo, particularly in humanized Rag2−/−γc−/− mice engrafted with either Tre-transduced primary CD4+ T cells, or Tre-transduced CD34+ hematopoietic stem and progenitor cells (HSC). Taken together, our data support the use of Tre-recombinase in novel therapy strategies aiming to provide a cure for HIV. [ABSTRACT FROM AUTHOR]

Despite complete or near-complete suppression of human immunodeficiency virus ( HIV) replication with combination antiretroviral therapy, both HIV and chronic inflammation/immune dysfunction persist indefinitely. Untangling the association between the virus and the host immune environment during therapy might lead to novel interventions aimed at either curing the infection or preventing the development of inflammation-associated end-organ disease. Chronic inflammation and immune dysfunction might lead to HIV persistence by causing virus production, generating new target cells, enabling infecting of activated and resting target cells, altering the migration patterns of susceptible target cells, increasing the proliferation of infected cells, and preventing normal HIV-specific clearance mechanisms from function. Chronic HIV production or replication might contribute to persistent inflammation and immune dysfunction. The rapidly evolving data on these issues strongly suggest that a vicious cycle might exist in which HIV persistence causes inflammation that in turn contributes to HIV persistence. [ABSTRACT FROM AUTHOR]

Comprehensive studies of the frequencies and absolute numbers of the various cell lineages that synthesize IL-17 in the blood and corresponding gastrointestinal (GI) tissues, their correlation with CD4+ Tregs, CD8+ Tregs, total and IFN-α synthesizing plasmacytoid dendritic cells (pDC) relative to plasma viral load in SIV infection has been lacking. The unique availability of SIV infected rhesus macaques (RM) classified as Elite Controllers (EC), and those with Low, Intermediate and High Viral Loads (HVL) provided a unique opportunity to address this issue. Results of these studies showed that EC demonstrated a remarkable ability to reverse changes that are induced acutely by SIV in the various cell lineages. Highlights of the differences between EC and HVL RM within Gastro-intestinal tissues (GIT) was the maintenance and/or increases in the levels of IL-17 synthesizing CD4, CD8, and NK cells and pDCs associated with slight decreases in the levels of CD4+ Tregs and IFN-α synthesizing pDCs in EC as compared with decreases in the levels of IL-17 synthesizing CD4, CD8 and NK cells associated with increases in pDCs and IFN-α synthesizing pDCs in HVL monkeys. A previously underappreciated role for CD8+ Tregs was also noted with a moderate increase in ECs but further increases of CD8+ Tregs with increasing VL in viremic monkeys. Positive correlations between plasma VL and decreases in the levels of Th17, Tc17, NK-17, CD4+ Tregs and increases in the levels of CD8+ Tregs, total and IFN-α synthesizing pDCs were also noted. This study also identified 2 additional IL-17+ subsets in GIT as CD3−/CD8+/NKG2a− and CD3+/CD8+/NKG2a+ subsets. Studies also suggest a limited role for IFN-α synthesizing pDCs in chronic immune activation despite persistent up-regulation of ISGs. Finally, elevated persistent innate immune responses appear associated with poor prognosis. These findings provide an initial foundation for markers important to follow for vaccine design. [ABSTRACT FROM AUTHOR]

Increasing evidence indicates that antibody-dependent cellular cytotoxicity (ADCC) contributes to the control of HIV/SIV infection. However, little is known about the ADCC function of natural killer (NK) cells in non-human primate model. Here we demonstrated that ADCC function of NK cells was significantly compromised in chronic SIV/SHIV infection, correlating closely with the expression of FcγRIIIa receptor (CD16) on NK cells. CD32, another class of IgG Fc receptors, was identified on NK cells with higher expression in the infected macaques and the blockade of CD32 impacted the ability of NK cells to respond to antibody-coated target cells. The inhibition of matrix metalloproteases (MMPs), a group of enzymes normally involved in tissue/receptor remodeling, could restore NK cell-mediated ADCC with increased CD16 expression on macaque NK cells. These data offer a clearer understanding of NK cell-mediated ADCC in rhesus macaques, which will allow us to evaluate the ADCC repertoire arising from preclinical vaccination studies in non-human primates and inform us in the future design of effective HIV vaccination strategies. [ABSTRACT FROM AUTHOR]

Problem Throughout the reproductive cycle and into early pregnancy, the normal endometrium undergoes changes in a range of leukocytes, epithelia, stromal fibroblasts, and vascular structures caused by intersecting effects of hormone balance and embryo implantation. The direct investigation in humans of reproductive tract responses during normal and physiologically altered cycles is not practical or feasible. Method and Study The aim of this study was to define immunological and morphological changes through immunohistological and morphometric evaluation of the endometrium throughout the menstrual cycle and the decidua during early gestation in the rhesus monkey, a tractable experimental animal model. Results A zone-dependent method for the immunohistological description of the rhesus uterine mucosa was established and showed that leukocyte infiltration, stromal cell decidualization, glandular and vascular responses were zone- and cell type-dependent, and changed throughout the cycle and early pregnancy. Morphological heterogeneity of uterine natural killer cells in the cycling endometrium and gestational decidua were consistent with the recent characterization of phenotypic subsets. Conclusions These data establish a morphological platform upon which to further study the regulation of endometrial responses to the hormonal mileau of pregnancy, the control of local leukocyte populations, and the responses to threatened pregnancy, infection, and inflammation. [ABSTRACT FROM AUTHOR]

NK cells are pivotal sentinels of the innate immune system and distinct subpopulations in peripheral blood have been described. A number of studies addressed HIV-induced alterations of NK cell phenotype and functionality mainly focusing on CD56dimCD16+ and CD56-2CD16+ NK cells. However, the impact of HIV-infection on CD56bright NK cells is less well understood. Here we report a rise of CD56bright NK cells in HIV-infected individuals, which lack CCR7-expression and strongly correlate with HIV viral load. CCR7-CD56bright NK cells were characterized by increased cytolytic potential, higher activation states and a more differentiated phenotype. These cells thus acquired a number of features of CD56dimCD16+ NK cells. Furthermore, CD56bright NK cells from HIV patients exhibited higher degranulation levels compared to uninfected individuals. Thus, chronic HIV-infection is associated with a phenotypic and functional shift of CD56bright NK cells, which provides a novel aspect of HIV-associated pathogenesis within the NK cell compartment. [ABSTRACT FROM AUTHOR]