ABSTRACT
Despite recent advances in asthma treatments, the search for novel therapies remains necessary because there are still patients with recurrent asthma exacerbations and poor responses to the existing treatments. Since group 2 innate lymphoid cells (ILC2) play a pivotal role in asthma by triggering and exacerbating type 2 inflammation, controlling ILC2s function is key to combating severe asthma. Mucosal-associated invariant T (MAIT) cells are innate-like T cells abundant in humans and are activated both in a T cell receptor-dependent and -independent manner. MAIT cells are composed of MAIT1 and MAIT17 based on the expression of transcription factors T-bet and RORγt, respectively. MAIT cells play pivotal roles in host defense against pathogens and in tissue repair and are essential for the maintenance of immunity and hemostasis. Our recent studies revealed that MAIT cells inhibit both ILC2 proliferation and functions in a mouse model of airway inflammation. MAIT cells may alleviate airway inflammation in two ways, by promoting airway epithelial cell barrier repair and by repressing ILC2s. Therefore, reagents that promote MAIT cell-mediated suppression of ILC2 proliferation and function, or designer MAIT cells (genetically engineered to suppress ILC2s or promote repair of airway damage), may be effective therapeutic agents for severe asthma.
Subject(s)
Asthma , Mucosal-Associated Invariant T Cells , Mice , Animals , Humans , Immunity, Innate , Lymphocytes , InflammationABSTRACT
Deglycosylated, live-attenuated SIV vaccines elicited protective immune responses against heterologous SIVsmE543-3, which differs from the vaccine strain SIVmac239 to levels similar to those across HIV-1 clades. Two thirds of the vaccinees contained the chronic SIVsmE543-3 infection (controllers), whereas one third did not (noncontrollers). In this study, we investigated immune correlates of heterologous challenge control in rhesus macaques of Burmese origin. Because depletion of CD8+ cells in the controllers by administration of anti-CD8α Ab abrogated the control of viral replication, CD8+ cells were required for the protective immune response. However, classical SIV-specific CD8+ T cells did not account for the protective immune response in all controllers. Instead, IL-15-responding CD8α+ cells, including CD8+ T and NK cells, were significantly higher in the controllers than those in the noncontrollers, before and after vaccination with deglycosylated SIV. It is well established that IL-15 signal transduction occurs through "trans-presentation" in which IL-15 complexed with IL-15Rα on monocytes, macrophages, and dendritic cells binds to IL-15 Rß/γ expressed on CD8+ T and NK cells. Accordingly, levels of IL-15 stimulation were strongly affected by the depletion of monocytes from PBMCs, implying key roles of innate immune cells. These results suggest that intrinsic IL-15 responsiveness may dictate the outcome of protective responses and may lead to optimized formulations of future broadly protective HIV vaccines.
Subject(s)
Immunity, Innate/immunology , Interleukin-15/immunology , SAIDS Vaccines/immunology , Simian Immunodeficiency Virus/immunology , Vaccines, Attenuated/immunology , Animals , Antibodies, Viral/immunology , CD8-Positive T-Lymphocytes/immunology , Killer Cells, Natural/immunology , Macaca mulatta , Male , Monocytes/immunology , Signal Transduction/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Vaccination/methods , Viral Load/immunology , Virus Replication/immunologyABSTRACT
The intestinal tract is a primary barrier to invading pathogens and contains immune cells, including lymphocytes and macrophages. We previously reported that CD163+CD206- (single-positive [SP]) interstitial macrophages of the lung are short-lived and succumb early to SIV infection. Conversely, CD163+CD206+ (double-positive [DP]) alveolar macrophages are long-lived, survive after SIV infection, and may contribute to the virus reservoir. This report characterizes analogous populations of macrophages in the intestinal tract of rhesus macaques (Macaca mulatta) with SIV/AIDS. By flow cytometry analysis, immunofluorescence staining, and confocal microscopy, CD163+CD206+ DP macrophages predominated in the lamina propria of uninfected animals, compared with CD163+CD206- SP macrophages, which predominated in the lamina propria in animals with SIV infection that were exhibiting AIDS. In submucosal areas, CD163+CD206+ DP macrophages predominated in both SIV-infected and uninfected macaques. Furthermore, BrdU-labeled CD163+CD206+ DP and CD163+CD206- SP macrophages recently arriving in the colon, which are both presumed to be shorter-lived, were observed to localize only in the lamina propria. Conversely, longer-lived CD163+CD206+ DP macrophages that retained dextran at least 2 mo after in vivo administration localized exclusively in the submucosa. This suggests that CD163+CD206+ DP intestinal macrophages of the lamina propria were destroyed after SIV infection and replaced by immature CD163+CD206- SP macrophages, whereas longer-lived CD163+CD206+ DP macrophages remained in the submucosa, supporting their potential role as an SIV/HIV tissue reservoir. Moreover, the DP macrophages in the submucosa, which differ from lamina propria DP macrophages, may be missed from pinch biopsy sampling, which may preclude detecting virus reservoirs for monitoring HIV cure.
Subject(s)
Colon/immunology , Intestinal Mucosa/immunology , Macrophages/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Animals , Antigens, CD/immunology , Antigens, Differentiation, Myelomonocytic/immunology , Cell Survival/immunology , Colon/pathology , Colon/virology , Female , Flow Cytometry , Intestinal Mucosa/pathology , Intestinal Mucosa/virology , Lectins, C-Type/immunology , Macaca mulatta , Macrophages/pathology , Male , Mannose Receptor , Mannose-Binding Lectins/immunology , Receptors, Cell Surface/immunology , Simian Acquired Immunodeficiency Syndrome/pathologyABSTRACT
Neutrophils, basophils, and monocytes are continuously produced in bone marrow via myelopoiesis, circulate in blood, and are eventually removed from circulation to maintain homeostasis. To quantitate the kinetics of myeloid cell movement during homeostasis, we applied 5-bromo-2'-deoxyuridine pulse labeling in healthy rhesus macaques (Macaca mulatta) followed by hematology and flow cytometry analyses. Results were applied to a mathematical model, and the blood circulating half-life and daily production, respectively, of each cell type from macaques aged 5-10 y old were calculated for neutrophils (1.63 ± 0.16 d, 1.42 × 109 cells/l/d), basophils (1.78 ± 0.30 d, 5.89 × 106 cells/l/d), and CD14+CD16- classical monocytes (1.01 ± 0.15 d, 3.09 × 108 cells/l/d). Classical monocytes were released into the blood circulation as early as 1 d after dividing, whereas neutrophils remained in bone marrow 4-5 d before being released. Among granulocytes, neutrophils and basophils exhibited distinct kinetics in bone marrow maturation time and blood circulation. With increasing chronological age, there was a significant decrease in daily production of neutrophils and basophils, but the half-life of these granulocytes remained unchanged between 3 and 19 y of age. In contrast, daily production of classical monocytes remained stable through 19 y of age but exhibited a significant decline in half-life. These results demonstrated relatively short half-lives and continuous replenishment of neutrophils, basophils, and classical monocytes during homeostasis in adult rhesus macaques with compensations observed during increasing chronological age.
Subject(s)
Aging/physiology , Myeloid Cells/physiology , Animals , Basophils/physiology , Bone Marrow Cells/physiology , Eosinophils/physiology , Half-Life , Homeostasis/physiology , Macaca mulatta , Male , Monocytes/physiology , Neutrophils/physiologyABSTRACT
Despite combination antiretroviral therapies making HIV a chronic rather than terminal condition for many people, the prevalence of HIV-associated neurocognitive disorders (HAND) is increasing. This is especially problematic for children living with HIV. Children diagnosed HAND rarely display the hallmark pathology of HIV encephalitis in adults, namely infected macrophages and multinucleated giant cells in the brain. This finding has also been documented in rhesus macaques infected perinatally with simian immunodeficiency virus (SIV). However, the extent and mechanisms of lack of susceptibility to encephalitis in perinatally HIV-infected children remain unclear. In the current study, we compared brains of macaques infected with pathogenic strains of SIV at different ages to determine neuropathology, correlates of neuroinflammation, and potential underlying mechanisms. Encephalitis was not found in the macaques infected within 24 h of birth despite similar high plasma viral load and high monocyte turnover. Macaques developed encephalitis only when they were infected after 4 months of age. Lower numbers of CCR5-positive cells in the brain, combined with a less leaky blood-brain barrier, may be responsible for the decreased virus infection in the brain and consequently the absence of encephalitis in newborn macaques infected with SIV.
Subject(s)
Blood-Brain Barrier/immunology , Brain Stem/immunology , Disease Resistance , Encephalitis, Viral/immunology , Frontal Lobe/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/pathogenicity , Age Factors , Animals , Animals, Newborn , Blood-Brain Barrier/pathology , Blood-Brain Barrier/virology , Brain Stem/pathology , Brain Stem/virology , Capillary Permeability/immunology , Encephalitis, Viral/genetics , Encephalitis, Viral/pathology , Encephalitis, Viral/virology , Frontal Lobe/pathology , Frontal Lobe/virology , Gene Expression , Macaca mulatta/virology , Macrophages/immunology , Macrophages/pathology , Macrophages/virology , Monocytes/immunology , Monocytes/pathology , Monocytes/virology , RNA, Viral/genetics , RNA, Viral/metabolism , Receptors, CCR5/genetics , Receptors, CCR5/immunology , Receptors, Virus/genetics , Receptors, Virus/immunology , Simian Acquired Immunodeficiency Syndrome/genetics , Simian Acquired Immunodeficiency Syndrome/pathology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/physiology , Viral LoadABSTRACT
Background: Tuberculosis (TB) and human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) profoundly affect the immune system and synergistically accelerate disease progression. It is believed that CD4+ T-cell depletion by HIV is the major cause of immunodeficiency and reactivation of latent TB. Previous studies demonstrated that blood monocyte turnover concurrent with tissue macrophage death from virus infection better predicted AIDS onset than CD4+ T-cell depletion in macaques infected with simian immunodeficiency virus (SIV). Methods: In this study, we describe the contribution of macrophages to the pathogenesis of Mycobacterium tuberculosis (Mtb)/SIV coinfection in a rhesus macaque model using in vivo BrdU labeling, immunostaining, flow cytometry, and confocal microscopy. Results: We found that increased monocyte and macrophage turnover and levels of SIV-infected lung macrophages correlated with TB reactivation. All Mtb/SIV-coinfected monkeys exhibited declines in CD4+ T cells regardless of reactivation or latency outcomes, negating lower CD4+ T-cell levels as a primary cause of Mtb reactivation. Conclusions: Results suggest that SIV-related damage to macrophages contributes to Mtb reactivation during coinfection. This also supports strategies to target lung macrophages for the treatment of TB.
Subject(s)
Latent Tuberculosis/immunology , Macrophages, Alveolar/immunology , Monocytes/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Tuberculosis/immunology , Animals , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/microbiology , CD4-Positive T-Lymphocytes/virology , Coinfection/immunology , Coinfection/microbiology , Coinfection/virology , Disease Models, Animal , Latent Tuberculosis/microbiology , Latent Tuberculosis/virology , Lymphocyte Depletion/methods , Macaca mulatta , Macrophages, Alveolar/microbiology , Macrophages, Alveolar/virology , Male , Monocytes/microbiology , Monocytes/virology , Mycobacterium tuberculosis/immunology , Simian Acquired Immunodeficiency Syndrome/microbiology , Simian Acquired Immunodeficiency Syndrome/virology , Tuberculosis/microbiology , Tuberculosis/virology , Viral Load/immunologyABSTRACT
Infant humans and rhesus macaques infected with the human or simian immunodeficiency virus (HIV or SIV), respectively, express higher viral loads and progress more rapidly to AIDS than infected adults. Activated memory CD4+ T cells in intestinal tissues are major primary target cells for SIV/HIV infection, and massive depletion of these cells is considered a major cause of immunodeficiency. Monocytes and macrophages are important cells of innate immunity and also are targets of HIV/SIV infection. We reported previously that a high peripheral blood monocyte turnover rate was predictive for the onset of disease progression to AIDS in SIV-infected adult macaques. The purpose of this study was to determine if earlier or higher infection of monocytes/macrophages contributes to the more rapid progression to AIDS in infants. We observed that uninfected infant rhesus macaques exhibited higher physiologic baseline monocyte turnover than adults. Early after SIV infection, the monocyte turnover further increased, and it remained high during progression to AIDS. A high percentage of terminal deoxynucleotidyltransferase dUTP nick end label (TUNEL)-positive macrophages in the lymph nodes (LNs) and intestine corresponded with an increasing number of macrophages derived from circulating monocytes (bromodeoxyuridine positive [BrdU+] CD163+), suggesting that the increased blood monocyte turnover was required to rapidly replenish destroyed tissue macrophages. Immunofluorescence analysis further demonstrated that macrophages were a significant portion of the virus-producing cells found in LNs, intestinal tissues, and lungs. The higher baseline monocyte turnover in infant macaques and subsequent macrophage damage by SIV infection may help explain the basis of more rapid disease progression to AIDS in infants.IMPORTANCE HIV infection progresses much more rapidly in pediatric cases than in adults; however, the mechanism for this difference is unclear. Using the rhesus macaque model, this work was performed to address why infants infected with SIV progress more quickly to AIDS than do adults. Earlier we reported that in adult rhesus macaques, increasing monocyte turnover reflected tissue macrophage damage by SIV and was predictive of terminal disease progression to AIDS. Here we report that uninfected infant rhesus macaques exhibited a higher physiological baseline monocyte turnover rate than adults. Furthermore, once infected with SIV, infants displayed further increased monocyte turnover that may have facilitated the accelerated progression to AIDS. These results support a role for monocytes and macrophages in the pathogenesis of SIV/HIV and begin to explain why infants are more prone to rapid disease progression.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , Macrophages/immunology , Monocytes/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Animals , Disease Models, Animal , Disease Progression , HIV Infections/immunology , HIV Infections/pathology , Humans , Macaca mulatta/virology , Macrophages/virology , Monocytes/virology , RNA, Viral/blood , Simian Acquired Immunodeficiency Syndrome/pathology , Viral LoadABSTRACT
Glycosylation of Env defines pathogenic properties of simian immunodeficiency virus (SIV). We previously demonstrated that pathogenic SIVmac239 and a live-attenuated, quintuple deglycosylated Env mutant (Δ5G) virus target CD4+ T cells residing in different tissues during acute infection. SIVmac239 and Δ5G preferentially infected distinct CD4+ T cells in secondary lymphoid organs (SLOs) and within the lamina propria of the small intestine, respectively (C. Sugimoto et al., J Virol 86:9323-9336, 2012, https://doi.org/10.1128/JVI.00948-12). Here, we studied the host responses relevant to SIV targeting of CXCR3+ CCR5+ CD4+ T cells in SLOs. Genome-wide transcriptome analyses revealed that Th1-polarized inflammatory responses, defined by expression of CXCR3 chemokines, were distinctly induced in the SIVmac239-infected animals. Consistent with robust expression of CXCL10, CXCR3+ T cells were depleted from blood in the SIVmac239-infected animals. We also discovered that elevation of CXCL10 expression in blood and SLOs was secondary to the induction of CD14+ CD16+ monocytes and MAC387+ macrophages, respectively. Since the significantly higher levels of SIV infection in SLOs occurred with a massive accumulation of infiltrated MAC387+ macrophages, T cells, dendritic cells (DCs), and residential macrophages near high endothelial venules, the results highlight critical roles of innate/inflammatory responses in SIVmac239 infection. Restricted infection in SLOs by Δ5G also suggests that glycosylation of Env modulates innate/inflammatory responses elicited by cells of monocyte/macrophage/DC lineages.IMPORTANCE We previously demonstrated that a pathogenic SIVmac239 virus and a live-attenuated, deglycosylated mutant Δ5G virus infected distinct CD4+ T cell subsets in SLOs and the small intestine, respectively (C. Sugimoto et al., J Virol 86:9323-9336, 2012, https://doi.org/10.1128/JVI.00948-12). Accordingly, infections with SIVmac239, but not with Δ5G, deplete CXCR3+ CCR5+ CD4+ T (Th1) cells during the primary infection, thereby compromising the cellular immune response. Thus, we hypothesized that distinct host responses are elicited by the infections with two different viruses. We found that SIVmac239 induced distinctly higher levels of inflammatory Th1 responses than Δ5G. In particular, SIVmac239 infection elicited robust expression of CXCL10, a chemokine for CXCR3+ cells, in CD14+ CD16+ monocytes and MAC387+ macrophages recently infiltrated in SLOs. In contrast, Δ5G infection elicited only modest inflammatory responses. These results suggest that the glycosylation of Env modulates the inflammatory/Th1 responses through the monocyte/macrophage subsets and elicits marked differences in SIV infection and clinical outcomes.
Subject(s)
CD4-Positive T-Lymphocytes/virology , Chemokine CXCL10/biosynthesis , Macrophages/immunology , Monocytes/immunology , Receptors, CXCR3/analysis , Simian Immunodeficiency Virus/growth & development , T-Lymphocyte Subsets/virology , Animals , CD4-Positive T-Lymphocytes/chemistry , Gene Expression , Gene Expression Profiling , Immunity, Innate , Macaca mulatta , Male , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/immunology , T-Lymphocyte Subsets/chemistryABSTRACT
To our knowledge, this study demonstrates for the first time that the AIDS virus differentially impacts two distinct subsets of lung macrophages. The predominant macrophages harvested by bronchoalveolar lavage (BAL), alveolar macrophages (AMs), are routinely used in studies on human lung macrophages, are long-lived cells, and exhibit low turnover. Interstitial macrophages (IMs) inhabit the lung tissue, are not recovered with BAL, are shorter-lived, and exhibit higher baseline turnover rates distinct from AMs. We examined the effects of SIV infection on AMs in BAL fluid and IMs in lung tissue of rhesus macaques. SIV infection produced massive cell death of IMs that contributed to lung tissue damage. Conversely, SIV infection induced minimal cell death of AMs, and these cells maintained the lower turnover rate throughout the duration of infection. This indicates that SIV produces lung tissue damage through destruction of IMs, whereas the longer-lived AMs may serve as a virus reservoir to facilitate HIV persistence.
Subject(s)
Lung Diseases/immunology , Lung/immunology , Macrophages, Alveolar/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Animals , Cell Death/immunology , Humans , Lung/pathology , Lung Diseases/pathology , Macaca mulatta , Macrophages, Alveolar/pathology , Simian Acquired Immunodeficiency Syndrome/pathologyABSTRACT
Monocyte and dendritic cell (DC) development was evaluated using in vivo BrdU pulse-chase analyses in rhesus macaques, and phenotype analyses of these cells in blood also were assessed by immunostaining and flow cytometry for comparisons among rhesus, cynomolgus, and pigtail macaques, as well as African green monkeys and humans. The nonhuman primate species and humans have three subsets of monocytes, CD14(+)CD16(-), CD14(+)CD16(+), and CD14(-)CD16(+) cells, which correspond to classical, intermediate, and nonclassical monocytes, respectively. In addition, there exist presently two subsets of DC, BDCA-1(+) myeloid DC and CD123(+) plasmacytoid DC, that were first confirmed in rhesus macaque blood. Following BrdU inoculation, labeled cells first appeared in CD14(+)CD16(-) monocytes, then in CD14(+)CD16(+) cells, and finally in CD14(-)CD16(+) cells, thus defining different stages of monocyte maturation. A fraction of the classical CD14(+)CD16(-) monocytes gradually expressed CD16(+) to become CD16(+)CD14(+) cells and subsequently matured into the nonclassical CD14(-)CD16(+) cell subset. The differentiation kinetics of BDCA-1(+) myeloid DC and CD123(+) plasmacytoid DC were distinct from the monocyte subsets, indicating differences in their myeloid cell origins. Results from studies utilizing nonhuman primates provide valuable information about the turnover, kinetics, and maturation of the different subsets of monocytes and DC using approaches that cannot readily be performed in humans and support further analyses to continue examining the unique myeloid cell origins that may be applied to address disease pathogenesis mechanisms and intervention strategies in humans.
Subject(s)
Cell Differentiation , Dendritic Cells/cytology , Dendritic Cells/metabolism , Monocytes/cytology , Monocytes/metabolism , Animals , Antigens, CD/metabolism , Bone Marrow Cells/cytology , Bone Marrow Cells/metabolism , CD11c Antigen/metabolism , Humans , Immunophenotyping , Macaca , Myeloid Cells/cytology , Myeloid Cells/metabolism , PhenotypeABSTRACT
UNLABELLED: Deletion of Gly-720 and Tyr-721 from a highly conserved GYxxØ trafficking signal in the SIVmac239 envelope glycoprotein cytoplasmic domain, producing a virus termed ΔGY, leads to a striking perturbation in pathogenesis in rhesus macaques (Macaca mulatta). Infected macaques develop immune activation and progress to AIDS, but with only limited and transient infection of intestinal CD4(+) T cells and an absence of microbial translocation. Here we evaluated ΔGY in pig-tailed macaques (Macaca nemestrina), a species in which SIVmac239 infection typically leads to increased immune activation and more rapid progression to AIDS than in rhesus macaques. In pig-tailed macaques, ΔGY also replicated acutely to high peak plasma RNA levels identical to those for SIVmac239 and caused only transient infection of CD4(+) T cells in the gut lamina propria and no microbial translocation. However, in marked contrast to rhesus macaques, 19 of 21 pig-tailed macaques controlled ΔGY replication with plasma viral loads of <15 to 50 RNA copies/ml. CD4(+) T cells were preserved in blood and gut for up to 100 weeks with no immune activation or disease progression. Robust antiviral CD4(+) T cell responses were seen, particularly in the gut. Anti-CD8 antibody depletion demonstrated CD8(+) cellular control of viral replication. Two pig-tailed macaques progressed to disease with persisting viremia and possible compensatory mutations in the cytoplasmic tail. These studies demonstrate a marked perturbation in pathogenesis caused by ΔGY's ablation of the GYxxØ trafficking motif and reveal, paradoxically, that viral control is enhanced in a macaque species typically predisposed to more pathogenic manifestations of simian immunodeficiency virus (SIV) infection. IMPORTANCE: The pathogenesis of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) reflects a balance between viral replication, host innate and adaptive antiviral immune responses, and sustained immune activation that in humans and Asian macaques is associated with persistent viremia, immune escape, and AIDS. Among nonhuman primates, pig-tailed macaques following SIV infection are predisposed to more rapid disease progression than are rhesus macaques. Here, we show that disruption of a conserved tyrosine-based cellular trafficking motif in the viral transmembrane envelope glycoprotein cytoplasmic tail leads in pig-tailed macaques to a unique phenotype in which high levels of acute viral replication are followed by elite control, robust cellular responses in mucosal tissues, and no disease. Paradoxically, control of this virus in rhesus macaques is only partial, and progression to AIDS occurs. This novel model should provide a powerful tool to help identify host-specific determinants for viral control with potential relevance for vaccine development.
Subject(s)
Amino Acid Motifs , CD4-Positive T-Lymphocytes/immunology , Immunity, Mucosal , Macaca nemestrina/virology , Sequence Deletion , Simian Acquired Immunodeficiency Syndrome/immunology , Viral Envelope Proteins/immunology , Animals , CD4-Positive T-Lymphocytes/virology , Disease Progression , Female , Gene Expression , Intestines/immunology , Intestines/virology , Macaca mulatta/virology , Male , Molecular Sequence Data , Mucous Membrane/immunology , Mucous Membrane/virology , Protein Sorting Signals , Protein Structure, Tertiary , Protein Transport , Simian Acquired Immunodeficiency Syndrome/pathology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/genetics , Simian Immunodeficiency Virus/immunology , Species Specificity , Viral Envelope Proteins/deficiency , Viral Envelope Proteins/genetics , Viral Load/genetics , Viral Load/immunology , Viremia/immunology , Viremia/pathology , Virus Replication/genetics , Virus Replication/immunologyABSTRACT
Alveolar macrophages (AMs) obtained by bronchoalveolar lavage (BAL) are commonly used to study lung macrophage-mediated immune responses. Questions remain, however, about whether AMs fully represent macrophage function in the lung. This study was performed to determine the contribution of interstitial macrophages (IMs) of lung tissue to pulmonary immunity and that are not present in BAL sampling. In vivo BrdU injection was performed to evaluate the kinetics and monocyte/tissue macrophage turnover in Indian rhesus macaques (Macaca mulatta). Lung macrophage phenotype and cell turnover were analyzed by flow cytometry and immunohistochemistry. AMs and IMs in lungs of rhesus macaques composed â¼70% of immune response cells in the lung. AMs represented a larger proportion of macrophages, â¼75-80%, and exhibited minimal turnover. Conversely, IMs exhibited higher turnover rates that were similar to those of blood monocytes during steady-state homeostasis. IMs also exhibited higher staining for TUNEL, suggesting a continuous transition of blood monocytes replacing IMs undergoing apoptosis. Although AMs appear static in steady-state homeostasis, increased influx of new AMs derived from monocytes/IMs was observed after BAL procedure. Moreover, ex vivo IFN-γ plus LPS treatment significantly increased intracellular expression of TNF-α in IMs, but not in AMs. These findings indicate that the longer-lived AMs obtained from BAL may not represent the entire pulmonary spectrum of macrophage responses, and shorter-lived IMs may function as the critical mucosal macrophage subset in the lung that helps to maintain homeostasis and protect against continuous pathogen exposure from the environment.
Subject(s)
Lung/immunology , Macaca mulatta/immunology , Macrophages, Alveolar/immunology , Macrophages/immunology , Animals , Antigens, CD/immunology , Antigens, CD/metabolism , Apoptosis/immunology , Bronchoalveolar Lavage Fluid/cytology , Bronchoalveolar Lavage Fluid/immunology , Flow Cytometry , Humans , Immunophenotyping , In Situ Nick-End Labeling , Interferon-gamma/immunology , Interferon-gamma/pharmacology , Lipopolysaccharides/immunology , Lipopolysaccharides/pharmacology , Lung/cytology , Lung/metabolism , Lung Diseases/immunology , Lung Diseases/metabolism , Lung Diseases/pathology , Macrophages/drug effects , Macrophages/metabolism , Macrophages, Alveolar/drug effects , Macrophages, Alveolar/metabolism , Male , Microscopy, Confocal , Monocytes/drug effects , Monocytes/immunology , Monocytes/metabolism , Tumor Necrosis Factor-alpha/immunology , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Nowadays, antibiotic resistance is a serious global health concern, for it is observed every- where on the earth. While antibiotic is effective for controlling pathogens, an inappropriate use of the antibiotic leads to antibiotic resistance. Given that the ability to develop novel anti- biotics is quite limited, a new strategy must be developed to fight against it. Mucosal- associated invariant T cells (MAITs) belong to a family of the innate-like T cells that bridges the gap between the innate and the adaptive immunity. We have generated iPSCs from MAITs and redifferentiated MAITs from the iPSCs. These MAITs exerted anti- mycobacterial activity in mice. Advent of such cells will pave the way to exploit a novel arsen- al against antibiotic resistance.
Subject(s)
Induced Pluripotent Stem Cells , Infection Control , Infections/therapy , Animals , Humans , MiceABSTRACT
Disruption of the conserved motif GYxxØ in the simian immunodeficiency virus (SIV) SIVmac239 envelope (Env) cytoplasmic tail resulted in a virus (ΔGY) that exhibited a high plasma peak but uniquely failed to acutely deplete mucosal CD4(+) T cells. Here, we show that ΔGY containing a flanking S727P mutation that was acquired in ΔGY-infected macaques reacquired the ability to rapidly deplete CD4(+) T cells in lamina propria. This suggests that the GYxxØ motif and S727P each contribute to SIV's targeting to mucosal tissues.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , Gene Products, env/genetics , Gene Products, env/metabolism , Mucous Membrane/immunology , Mutation, Missense , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/genetics , Amino Acid Motifs , Animals , CD4 Lymphocyte Count , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/virology , Gene Products, env/chemistry , Macaca , Male , Mucous Membrane/virology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/chemistry , Simian Immunodeficiency Virus/metabolismABSTRACT
A hallmark of pathogenic simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV) infections is the rapid and near-complete depletion of mucosal CD4(+) T lymphocytes from the gastrointestinal tract. Loss of these cells and disruption of epithelial barrier function are associated with microbial translocation, which has been proposed to drive chronic systemic immune activation and disease progression. Here, we evaluate in rhesus macaques a novel attenuated variant of pathogenic SIVmac239, termed ΔGY, which contains a deletion of a Tyr and a proximal Gly from a highly conserved YxxØ trafficking motif in the envelope cytoplasmic tail. Compared to SIVmac239, ΔGY established a comparable acute peak of viremia but only transiently infected lamina propria and caused little or no acute depletion of mucosal CD4(+) T cells and no detectable microbial translocation. Nonetheless, these animals developed T-cell activation and declining peripheral blood CD4(+) T cells and ultimately progressed with clinical or pathological features of AIDS. ΔGY-infected animals also showed no infection of macrophages or central nervous system tissues even in late-stage disease. Although the ΔGY mutation persisted, novel mutations evolved, including the formation of new YxxØ motifs in two of four animals. These findings indicate that disruption of this trafficking motif by the ΔGY mutation leads to a striking alteration in anatomic distribution of virus with sparing of lamina propria and a lack of microbial translocation. Because these animals exhibited wild-type levels of acute viremia and immune activation, our findings indicate that these pathological events are dissociable and that immune activation unrelated to gut damage can be sufficient for the development of AIDS.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/virology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/pathogenicity , Viral Envelope Proteins/metabolism , Virulence Factors/metabolism , Animals , Central Nervous System/virology , Disease Progression , Female , Gastrointestinal Tract/immunology , Intestinal Mucosa/immunology , Macaca mulatta , Macrophages/virology , Male , Molecular Sequence Data , Mutant Proteins/genetics , Mutant Proteins/metabolism , Protein Transport , RNA, Viral/genetics , Sequence Analysis, DNA , Sequence Deletion , Simian Acquired Immunodeficiency Syndrome/pathology , Viral Envelope Proteins/genetics , Virulence Factors/geneticsABSTRACT
The function of mucosal-associated invariant T (MAIT) cells, a burgeoning member of innate-like T cells abundant in humans and implicated in many diseases, remains obscure. To explore this, mice with a rearranged T cell receptor (TCR) α or ß locus, specific for MAIT cells, were generated via induced pluripotent stem cells derived from MAIT cells and were designated Vα19 and Vß8 mice, respectively. Both groups of mice expressed large numbers of MAIT cells. The MAIT cells from these mice were activated by cytokines and an agonist to produce IFN-γ and IL-17. While Vß8 mice showed resistance in a cancer metastasis model, Vα19 mice did not. Adoptive transfer of MAIT cells from the latter into the control mice, however, recapitulated the resistance. These mice present an implication for understanding the role of MAIT cells in health and disease and in developing treatments for the plethora of diseases in which MAIT cells are implicated.
ABSTRACT
Glycans of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) play pivotal roles in modulating virus-target cell interactions. We have previously reported that, whereas SIVmac239 is pathogenic, its deglycosylated essentially nonpathogenic mutant (Δ5G) serves as a live-attenuated vaccine, although both replicate similarly during primary infection. These findings prompted us to determine whether such a polarized clinical outcome was due to differences in the immune tissues targeted by these viruses, where functionally and phenotypically different memory CD4(+) T cells reside. The results showed that Δ5G replicates in secondary lymphoid tissue (SLT) at 1- to 2-log-lower levels than SIVmac239, whereas SIVmac239-infected but not Δ5G-infected animals deplete CXCR3(+) CCR5(+) transitional memory (TrM) CD4(+) T cells. An early robust Δ5G replication was localized to small intestinal tissue, especially the lamina propria (effector site) rather than isolated lymphoid follicles (inductive site) and was associated with the induction and depletion of CCR6(+) CXCR3(-) CCR5(+) effector memory CD4(+) T cells. These results suggest that differential glycosylation of Env dictates the type of tissue-resident CD4(+) T cells that are targeted, which leads to pathogenic infection of TrM-Th1 cells in SLT and nonpathogenic infection of Th17 cells in the small intestine, respectively.
Subject(s)
Gene Products, env/metabolism , Immune System/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/metabolism , Animals , Gene Products, env/genetics , Glycosylation , HIV/genetics , HIV/immunology , HIV/metabolism , HIV Infections/immunology , HIV Infections/virology , Humans , Immune System/virology , Immunologic Memory , Intestines/immunology , Intestines/virology , Macaca mulatta , Organ Specificity , Simian Immunodeficiency Virus/genetics , Simian Immunodeficiency Virus/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/virologyABSTRACT
BACKGROUND: Sigma H (sigH) is a major Mycobacterium tuberculosis (Mtb) stress response factor. It is induced in response to heat, oxidative stress, cell wall damage, and hypoxia. Infection of macrophages with the Δ-sigH mutant generates more potent innate immune response than does infection with Mtb. The mutant is attenuated for pathology in mice. METHODS: We used a nonhuman primate (NHP) model of acute tuberculosis, to better understand the phenotype of the Δ-sigH mutant in vivo. NHPs were infected with high doses of Mtb or the mutant, and the progression of tuberculosis was analyzed in both groups using clinical, pathological, microbiological, and immunological parameters. RESULTS: Animals exposed to Mtb rapidly progressed to acute pulmonary tuberculosis as indicated by worsening clinical correlates, high lung bacterial burden, and granulomatous immunopathology. All the animals rapidly succumbed to tuberculosis. On the other hand, the NHPs exposed to the Mtb:Δ-sigH mutant did not exhibit acute tuberculosis, instead showing significantly blunted disease. These NHPs survived the entire duration of the study. CONCLUSIONS: The Mtb:Δ-sigH mutant is completely attenuated for bacterial burden as well as immunopathology in NHPs. SigH and its regulon are required for complete virulence in primates. Further studies are needed to identify the molecular mechanism of this attenuation.
Subject(s)
Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial/physiology , Lung/immunology , Lung/microbiology , Mycobacterium tuberculosis/metabolism , Sigma Factor/metabolism , Tuberculosis, Pulmonary/microbiology , Animals , Bacterial Proteins/genetics , Gene Expression Profiling , Granuloma , Immunohistochemistry , Macaca mulatta , Mycobacterium tuberculosis/genetics , Sigma Factor/genetics , Tuberculosis, Pulmonary/pathologyABSTRACT
Cells of the myeloid lineage are significant targets for human immunodeficiency virus (HIV) in humans and simian immunodeficiency virus (SIV) in monkeys. Monocytes play critical roles in innate and adaptive immunity during inflammation. We hypothesize that specific subsets of monocytes expand with AIDS and drive central nervous system (CNS) disease. Additionally, there may be expansion of cells from the bone marrow through blood with subsequent macrophage accumulation in tissues driving pathogenesis. To identify monocytes that recently emigrated from bone marrow, we used 5-bromo-2'-deoxyuridine (BrdU) labeling in a longitudinal study of SIV-infected CD8+ T lymphocyte depleted macaques. Monocyte expansion and kinetics in blood was assessed and newly migrated monocyte/macrophages were identified within the CNS. Five animals developed rapid AIDS with differing severity of SIVE. The percentages of BrdU+ monocytes in these animals increased dramatically, early after infection, peaking at necropsy where the percentage of BrdU+ monocytes correlated with the severity of SIVE. Early analysis revealed changes in the percentages of BrdU+ monocytes between slow and rapid progressors as early as 8 days and consistently by 27 days post infection. Soluble CD163 (sCD163) in plasma correlated with the percentage of BrdU+ monocytes in blood, demonstrating a relationship between monocyte activation and expansion with disease. BrdU+ monocytes/macrophages were found within perivascular spaces and SIVE lesions. The majority (80-90%) of the BrdU+ cells were Mac387+ that were not productively infected. There was a minor population of CD68+BrdU+ cells (<10%), very few of which were infected (<1% of total BrdU+ cells). Our results suggest that an increased rate of monocyte recruitment from bone marrow into the blood correlates with rapid progression to AIDS, and the magnitude of BrdU+ monocytes correlates with the severity of SIVE.