Publications by authors named "James A Lederer"

70 Publications

Mechanisms driving neutrophil-induced T-cell immunoparalysis in ovarian cancer.

Cancer Immunol Res 2021 May 14. Epub 2021 May 14.

Medicine and Immunology, Roswell Park Cancer Institute

T-cell activation and expansion in the tumor microenvironment (TME) are critical for antitumor immunity. Neutrophils in the TME acquire a complement-dependent T-cell suppressor phenotype that is characterized by inhibition of T-cell proliferation and activation through mechanisms distinct from those of myeloid-derived suppressor cells. In this study, we used ascites fluid supernatants (ASC) from patients with ovarian cancer as an authentic component of the TME to evaluate the effects of ASC on neutrophil function and mechanisms for neutrophil-driven immune suppression. ASC prolonged neutrophil lifespan, decreased neutrophil density, and induced nuclear hypersegmentation. Mass cytometry analysis showed that ASC induced 15 distinct neutrophil clusters. ASC stimulated complement deposition and signaling in neutrophils resulting in surface mobilization of granule constituents, including NADPH oxidase. NADPH oxidase activation and phosphatidylserine signaling were required for neutrophil suppressor function, although we did not observe a direct role of extracellular reactive oxygen species in inhibiting T-cell proliferation. Post-operative surgical drainage fluid also induced a complement-dependent neutrophil suppressor phenotype, pointing to this effect as a general response to injury. Like circulating lymphocytes, ASC-activated neutrophils caused complement-dependent suppression of tumor-associated lymphocytes. ASC-activated neutrophils adhered to T cells and caused trogocytosis of T-cell membranes. These injury and signaling cues resulted in T-cell immunoparalysis characterized by impaired NFAT translocation, IL2 production, glucose uptake, mitochondrial function, and mTOR activation. Our results demonstrate complement-dependent priming of neutrophil effector functions in the TME inducing a T-cell non-responsiveness distinct from established checkpoint pathways and identify targets for immunotherapy.
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http://dx.doi.org/10.1158/2326-6066.CIR-20-0922DOI Listing
May 2021

Mesenchymal stromal cells expressing a dominant-negative high mobility group A1 transgene exhibit improved function during sepsis.

J Leukoc Biol 2021 Jan 13. Epub 2021 Jan 13.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.

High mobility group (HMG)A proteins are nonhistone chromatin proteins that bind to the minor groove of DNA, interact with transcriptional machinery, and facilitate DNA-directed nuclear processes. HMGA1 has been shown to regulate genes involved with systemic inflammatory processes. We hypothesized that HMGA1 is important in the function of mesenchymal stromal cells (MSCs), which are known to modulate inflammatory responses due to sepsis. To study this process, we harvested MSCs from transgenic (Tg) mice expressing a dominant-negative (dn) form of HMGA1 in mesenchymal cells. MSCs harvested from Tg mice contained the dnHMGA1 transgene, and transgene expression did not change endogenous HMGA1 levels. Immunophenotyping of the cells, along with trilineage differentiation revealed no striking differences between Tg and wild-type (WT) MSCs. However, Tg MSCs growth was decreased compared with WT MSCs, although Tg MSCs were more resistant to oxidative stress-induced death and expressed less IL-6. Tg MSCs administered after the onset of Escherichia coli-induced sepsis maintained their ability to improve survival when given in a single dose, in contrast with WT MSCs. This survival benefit of Tg MSCs was associated with less tissue cell death, and also a reduction in tissue neutrophil infiltration and expression of neutrophil chemokines. Finally, Tg MSCs promoted bacterial clearance and enhanced neutrophil phagocytosis, in part through their increased expression of stromal cell-derived factor-1 compared with WT MSCs. Taken together, these data demonstrate that expression of dnHMGA1 in MSCs provides a functional advantage of the cells when administered during bacterial sepsis.
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http://dx.doi.org/10.1002/JLB.4A0720-424RDOI Listing
January 2021

Quick COVID-19 Healers Sustain Anti-SARS-CoV-2 Antibody Production.

Cell 2020 12 3;183(6):1496-1507.e16. Epub 2020 Nov 3.

Department of Medicine, Division of Allergy and Immunology, Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Massachusetts Consortium on Pathogen Readiness, Boston, MA 02115, USA. Electronic address:

Antibodies are key immune effectors that confer protection against pathogenic threats. The nature and longevity of the antibody response to SARS-CoV-2 infection are not well defined. We charted longitudinal antibody responses to SARS-CoV-2 in 92 subjects after symptomatic COVID-19. Antibody responses to SARS-CoV-2 are unimodally distributed over a broad range, with symptom severity correlating directly with virus-specific antibody magnitude. Seventy-six subjects followed longitudinally to ∼100 days demonstrated marked heterogeneity in antibody duration dynamics. Virus-specific IgG decayed substantially in most individuals, whereas a distinct subset had stable or increasing antibody levels in the same time frame despite similar initial antibody magnitudes. These individuals with increasing responses recovered rapidly from symptomatic COVID-19 disease, harbored increased somatic mutations in virus-specific memory B cell antibody genes, and had persistent higher frequencies of previously activated CD4 T cells. These findings illuminate an efficient immune phenotype that connects symptom clearance speed to differential antibody durability dynamics.
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http://dx.doi.org/10.1016/j.cell.2020.10.051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608032PMC
December 2020

Augmenting emergency granulopoiesis with CpG conditioned mesenchymal stromal cells in murine neutropenic sepsis.

Blood Adv 2020 10;4(19):4965-4979

Department of Surgery.

Patients with immune deficiencies from cancers and associated treatments represent a growing population within the intensive care unit with increased risk of morbidity and mortality from sepsis. Mesenchymal stromal cells (MSCs) are an integral part of the hematopoietic niche and express toll-like receptors, making them candidate cells to sense and translate pathogenic signals into an innate immune response. In this study, we demonstrate that MSCs administered therapeutically in a murine model of radiation-associated neutropenia have dual actions to confer a survival benefit in Pseudomonas aeruginosa pneumo-sepsis that is not from improved bacterial clearance. First, MSCs augment the neutrophil response to infection, an effect that is enhanced when MSCs are preconditioned with CpG oligodeoxynucleotide, a toll-like receptor 9 agonist. Using cytometry by time of flight, we identified proliferating neutrophils (Ly6GlowKi-67+) as the main expanded cell population within the bone marrow. Further analysis revealed that CpG-MSCs expand a lineage restricted progenitor population (Lin-Sca1+C-kit+CD150-CD48+) in the bone marrow, which corresponded to a doubling in the myeloid proliferation and differentiation potential in response to infection compared with control. Despite increased neutrophils, no reduction in organ bacterial count was observed between experimental groups. However, the second effect exerted by CpG-MSCs is to attenuate organ damage, particularly in the lungs. Neutrophils obtained from irradiated mice and cocultured with CpG-MSCs had decreased neutrophil extracellular trap formation, which was associated with decreased citrullinated H3 staining in the lungs of mice given CpG-MSCs in vivo. Thus, this preclinical study provides evidence for the therapeutic potential of MSCs in neutropenic sepsis.
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http://dx.doi.org/10.1182/bloodadvances.2020002556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7556132PMC
October 2020

Viral epitope profiling of COVID-19 patients reveals cross-reactivity and correlates of severity.

Science 2020 11 29;370(6520). Epub 2020 Sep 29.

Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, MA, USA.

Understanding humoral responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for improving diagnostics, therapeutics, and vaccines. Deep serological profiling of 232 coronavirus disease 2019 (COVID-19) patients and 190 pre-COVID-19 era controls using VirScan revealed more than 800 epitopes in the SARS-CoV-2 proteome, including 10 epitopes likely recognized by neutralizing antibodies. Preexisting antibodies in controls recognized SARS-CoV-2 ORF1, whereas only COVID-19 patient antibodies primarily recognized spike protein and nucleoprotein. A machine learning model trained on VirScan data predicted SARS-CoV-2 exposure history with 99% sensitivity and 98% specificity; a rapid Luminex-based diagnostic was developed from the most discriminatory SARS-CoV-2 peptides. Individuals with more severe COVID-19 exhibited stronger and broader SARS-CoV-2 responses, weaker antibody responses to prior infections, and higher incidence of cytomegalovirus and herpes simplex virus 1, possibly influenced by demographic covariates. Among hospitalized patients, males produce stronger SARS-CoV-2 antibody responses than females.
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http://dx.doi.org/10.1126/science.abd4250DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857405PMC
November 2020

Multiplexed Plasma Immune Mediator Signatures Can Differentiate Sepsis From NonInfective SIRS: American Surgical Association 2020 Annual Meeting Paper.

Ann Surg 2020 10;272(4):604-610

Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.

Objectives: Sepsis and sterile both release "danger signals' that induce the systemic inflammatory response syndrome (SIRS). So differentiating infection from SIRS can be challenging. Precision diagnostic assays could limit unnecessary antibiotic use, improving outcomes.

Methods: After surveying human leukocyte cytokine production responses to sterile damage-associated molecular patterns (DAMPs), bacterial pathogen-associated molecular patterns, and bacteria we created a multiplex assay for 31 cytokines. We then studied plasma from patients with bacteremia, septic shock, "severe sepsis," or trauma (ISS ≥15 with circulating DAMPs) as well as controls. Infections were adjudicated based on post-hospitalization review. Plasma was studied in infection and injury using univariate and multivariate means to determine how such multiplex assays could best distinguish infective from noninfective SIRS.

Results: Infected patients had high plasma interleukin (IL)-6, IL-1α, and triggering receptor expressed on myeloid cells-1 (TREM-1) compared to controls [false discovery rates (FDR) <0.01, <0.01, <0.0001]. Conversely, injury suppressed many mediators including MDC (FDR <0.0001), TREM-1 (FDR <0.001), IP-10 (FDR <0.01), MCP-3 (FDR <0.05), FLT3L (FDR <0.05), Tweak, (FDR <0.05), GRO-α (FDR <0.05), and ENA-78 (FDR <0.05). In univariate studies, analyte overlap between clinical groups prevented clinical relevance. Multivariate models discriminated injury and infection much better, with the 2-group random-forest model classifying 11/11 injury and 28/29 infection patients correctly in out-of-bag validation.

Conclusions: Circulating cytokines in traumatic SIRS differ markedly from those in health or sepsis. Variability limits the accuracy of single-mediator assays but machine learning based on multiplexed plasma assays revealed distinct patterns in sepsis- and injury-related SIRS. Defining biomarker release patterns that distinguish specific SIRS populations might allow decreased antibiotic use in those clinical situations. Large prospective studies are needed to validate and operationalize this approach.
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http://dx.doi.org/10.1097/SLA.0000000000004379DOI Listing
October 2020

Trauma induces expansion and activation of a memory-like Treg population.

J Leukoc Biol 2021 03 12;109(3):645-656. Epub 2020 Jun 12.

Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.

CD4+ regulatory T cells (Tregs) are acutely activated by traumatic injury, which suggests that they may react to injury with similar kinetics as memory T cells. Here, we used a mouse burn trauma model to screen for memory-like T cell responses to injury by transferring T cells from sham or burn CD45.1 mice into CD45.2 mice and performing secondary injuries in recipient mice. Among all T cell subsets that were measured, only Tregs expanded in response to secondary injury. The expanded Tregs were a CD44 /CD62L subpopulation, markers indicative of memory T cells. CyTOF (cytometry by time-of-flight) mass cytometry was used to demonstrate that injury-expanded Tregs expressed higher levels of CD44, CTLA-4, ICOS, GITR, and Helios than Tregs from noninjured mice. Next, we tested whether a similar population of Tregs might react acutely to burn trauma. We observed that Tregs with a phenotype that matched the injury-expanded Tregs were activated by 6 h after injury. To test if Treg activation by trauma requires functional MHC class II, we measured trauma-induced Treg activation in MHC class II gene deficient (MHCII ) mice or in mice that were given Fab fragment of anti-MHC class II antibody to block TCR activation. Injury-induced Treg activation occurred in normal mice but only partial activation was detected in MHCII mice or in mice that were given Fab anti-MHCII antibody. These findings demonstrate that trauma activates a memory-like Treg subpopulation and that Treg activation by injury is partially dependent on TCR signaling by an MHC class II dependent mechanism.
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http://dx.doi.org/10.1002/JLB.4A0520-122RDOI Listing
March 2021

Th17 reprogramming of T cells in systemic juvenile idiopathic arthritis.

JCI Insight 2020 03 26;5(6). Epub 2020 Mar 26.

Division of Immunology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Systemic juvenile idiopathic arthritis (sJIA) begins with fever, rash, and high-grade systemic inflammation but commonly progresses to a persistent afebrile arthritis. The basis for this transition is unknown. To evaluate a role for lymphocyte polarization, we characterized T cells from patients with acute and chronic sJIA using flow cytometry, mass cytometry, and RNA sequencing. Acute and chronic sJIA each featured an expanded population of activated Tregs uncommon in healthy controls or in children with nonsystemic JIA. In acute sJIA, Tregs expressed IL-17A and a gene expression signature reflecting Th17 polarization. In chronic sJIA, the Th17 transcriptional signature was identified in T effector cells (Teffs), although expression of IL-17A at the protein level remained rare. Th17 polarization was abrogated in patients responding to IL-1 blockade. These findings identify evolving Th17 polarization in sJIA that begins in Tregs and progresses to Teffs, likely reflecting the impact of the cytokine milieu and consistent with a biphasic model of disease pathogenesis. The results support T cells as a potential treatment target in sJIA.
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http://dx.doi.org/10.1172/jci.insight.132508DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7213804PMC
March 2020

Circulating Factors in Trauma Plasma Activate Specific Human Immune Cell Subsets.

Injury 2020 Apr 4;51(4):819-829. Epub 2020 Mar 4.

Brigham and Women's Hospital, 75 Francis St., Boston, MA, 02115, United States. Electronic address:

Background: Trauma causes tissue injury that results in the release of damage associated molecular patterns (DAMPs) and other mediators at the site of injury and systemically. Such mediators disrupt immune system homeostasis and may activate multicellular immune responses with downstream complications such as the development of infections and sepsis. To characterize these alterations, we used time-of-flight mass cytometry to determine how trauma plasma affects normal peripheral blood mononuclear cell (PBMC) activation to gain insights into the kinetics and nature of trauma-induced circulating factors on human immune cell populations. A better understanding of the components that activate cells in trauma may aid in the discovery of therapeutic targets.

Methods: PBMCs from healthy volunteers were cultured with 5% plasma (healthy, trauma-1day, or trauma-3day) or known DAMPs for 24 h. Samples were stained with a broad immunophenotyping CyTOF antibody panel. Multiplex (Luminex) cytokine assays were used to measure differences in multiple cytokine levels in healthy and trauma plasma samples.

Results: Plasma from day 1, but not day 3 trauma patients induced the acute expansion of CD11c+ NK cells and CD73+/CCR7+ CD8 T cell subpopulations. Additionally, trauma plasma did not induce CD4+ T cell expansion but did cause a phenotypic shift towards CD38+/CCR7+ expressing CD4+ T cells. Multiplex analysis of cytokines by Luminex showed increased levels of IL-1RA, IL-6 and IL-15 in trauma-1day plasma. Similar to trauma day 1 plasma, PBMC stimulation with known DAMPs showed activation and expansion of CD11c+ NK cells.

Conclusions: We hypothesized that circulating factors in trauma plasma would induce phenotypic activation of normal human immune cell subsets. Using an unbiased approach, we identified specific changes in immune cell subsets that respond to trauma plasma. Additionally, CD11c+ NK cells expanded in response to DAMPs and LPS, suggesting they may also be responding to similar components in trauma plasma. Collectively, our data demonstrate that the normal PBMC response to trauma plasma involves marked changes in specific subsets of NK and CD8+ T cell populations. Future studies will target the function of these trauma plasma reactive immune cell subsets. These findings have important implications for the field of acute traumatic injuries.
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http://dx.doi.org/10.1016/j.injury.2020.03.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7441590PMC
April 2020

Expression of Stromal Cell-Derived Factor-1 by Mesenchymal Stromal Cells Impacts Neutrophil Function During Sepsis.

Crit Care Med 2020 05;48(5):e409-e417

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.

Objectives: Sepsis results in organ dysfunction caused by a dysregulated host response, in part related to the immune response of a severe infection. Mesenchymal stromal cells are known to modulate the immune response, and expression of stromal cell-derived factor-1 regulates mobilization of neutrophils from the bone marrow. We are investigating the importance of stromal cell-derived factor-1 in mesenchymal stromal cells and its role in promoting neutrophil function after the onset of cecal ligation and puncture-induced sepsis. Stromal cell-derived factor-1 expression was silenced in mesenchymal stromal cells, compared with the control scrambled construct mesenchymal stromal cells.

Design: Animal study and cell culture.

Setting: Laboratory investigation.

Subjects: BALB/c mice.

Interventions: Polymicrobial sepsis was induced by cecal ligation and puncture. shSCR mesenchymal stromal cells and shSDF-1 mesenchymal stromal cells were delivered by tail vein injections to septic mice. The mice were assessed for survival, bacterial clearance, and the inflammatory response during sepsis in each of the groups. Mesenchymal stromal cells were also assessed for their ability to promote bacterial phagocytosis by neutrophils.

Measurements And Main Results: Injection of shSCR mesenchymal stromal cells after the onset of sepsis led to an increase in mouse survival (70%) at 7 days, whereas survival of mice receiving shSDF-1 mesenchymal stromal cells was significantly diminished (33%). The loss of survival benefit in mice receiving shSDF-1 mesenchymal stromal cells was associated with less efficient bacterial clearance compared with shSCR mesenchymal stromal cells. Although shSCR mesenchymal stromal cells, or their conditioned medium, were able to increase neutrophil phagocytosis of bacteria, this effect was significantly blunted with shSDF-1 mesenchymal stromal cells. Assessment of peritoneal inflammation revealed that neutrophils were significantly increased and more immature in septic mice receiving shSDF-1 mesenchymal stromal cells. This response was associated with hypocellularity and increased neutrophil death in the bone marrow of mice receiving shSDF-1 mesenchymal stromal cells.

Conclusions: Expression of stromal cell-derived factor-1 in mesenchymal stromal cells enhances neutrophil function with increased phagocytosis, more efficient clearance of bacteria, and bone marrow protection from depletion of cellular reserves during sepsis.
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http://dx.doi.org/10.1097/CCM.0000000000004244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7556326PMC
May 2020

PD-1hiCXCR5- T peripheral helper cells promote B cell responses in lupus via MAF and IL-21.

JCI Insight 2019 10 17;4(20). Epub 2019 Oct 17.

Division of Rheumatology, Immunology, and Allergy.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by pathologic T cell-B cell interactions and autoantibody production. Defining the T cell populations that drive B cell responses in SLE may enable design of therapies that specifically target pathologic cell subsets. Here, we evaluated the phenotypes of CD4+ T cells in the circulation of 52 SLE patients drawn from multiple cohorts and identified a highly expanded PD-1hiCXCR5-CD4+ T cell population. Cytometric, transcriptomic, and functional assays demonstrated that PD-1hiCXCR5-CD4+ T cells from SLE patients are T peripheral helper (Tph) cells, a CXCR5- T cell population that stimulates B cell responses via IL-21. The frequency of Tph cells, but not T follicular helper (Tfh) cells, correlated with both clinical disease activity and the frequency of CD11c+ B cells in SLE patients. PD-1hiCD4+ T cells were found within lupus nephritis kidneys and correlated with B cell numbers in the kidney. Both IL-21 neutralization and CRISPR-mediated deletion of MAF abrogated the ability of Tph cells to induce memory B cell differentiation into plasmablasts in vitro. These findings identify Tph cells as a highly expanded T cell population in SLE and suggest a key role for Tph cells in stimulating pathologic B cell responses.
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http://dx.doi.org/10.1172/jci.insight.130062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824311PMC
October 2019

Accelerating Medicines Partnership: Organizational Structure and Preliminary Data From the Phase 1 Studies of Lupus Nephritis.

Arthritis Care Res (Hoboken) 2020 02 13;72(2):233-242. Epub 2020 Jan 13.

Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York.

The Accelerating Medicines Partnership (AMP) Lupus Network was established as a partnership between the National Institutes of Health, pharmaceutical companies, nonprofit stakeholders, and lupus investigators across multiple academic centers to apply high-throughput technologies to the analysis of renal tissue, urine, and blood from patients with lupus nephritis (LN). The AMP network provides publicly accessible data to the community with the goal of generating new scientific hypotheses and improving diagnostic and therapeutic tools so as to improve disease outcomes. We present here a description of the structure of the AMP Lupus Network and a summary of the preliminary results from the phase 1 studies. The successful completion of phase 1 sets the stage for analysis of a large cohort of LN samples in phase 2 and provides a model for establishing similar discovery cohorts.
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http://dx.doi.org/10.1002/acr.24066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992476PMC
February 2020

High-dimensional analysis reveals a pathogenic role of inflammatory monocytes in experimental diffuse alveolar hemorrhage.

JCI Insight 2019 08 8;4(15). Epub 2019 Aug 8.

Division of Immunology, Boston Children's Hospital, Boston, Massachusetts, USA.

Diffuse alveolar hemorrhage (DAH) is a life-threatening pulmonary complication associated with systemic lupus erythematosus, vasculitis, and stem cell transplant. Little is known about the pathophysiology of DAH, and no targeted therapy is currently available. Pristane treatment in mice induces systemic autoimmunity and lung hemorrhage that recapitulates hallmark pathologic features of human DAH. Using this experimental model, we performed high-dimensional analysis of lung immune cells in DAH by mass cytometry and single-cell RNA sequencing. We found a large influx of myeloid cells to the lungs in DAH and defined the gene expression profile of infiltrating monocytes. Bone marrow-derived inflammatory monocytes actively migrated to the lungs and homed adjacent to blood vessels. Using 3 models of monocyte deficiency and complementary transfer studies, we established a central role of inflammatory monocytes in the development of DAH. We further found that the myeloid transcription factor interferon regulatory factor 8 is essential to the development of both DAH and type I interferon-dependent autoimmunity. These findings collectively reveal monocytes as a potential treatment target in DAH.
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http://dx.doi.org/10.1172/jci.insight.129703DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6693829PMC
August 2019

The immune cell landscape in kidneys of patients with lupus nephritis.

Nat Immunol 2019 07 17;20(7):902-914. Epub 2019 Jun 17.

Division of Rheumatology, Johns Hopkins University, Baltimore, MD, USA.

Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies.
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http://dx.doi.org/10.1038/s41590-019-0398-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6726437PMC
July 2019

Defining inflammatory cell states in rheumatoid arthritis joint synovial tissues by integrating single-cell transcriptomics and mass cytometry.

Nat Immunol 2019 07 6;20(7):928-942. Epub 2019 May 6.

Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.

To define the cell populations that drive joint inflammation in rheumatoid arthritis (RA), we applied single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq) and flow cytometry to T cells, B cells, monocytes, and fibroblasts from 51 samples of synovial tissue from patients with RA or osteoarthritis (OA). Utilizing an integrated strategy based on canonical correlation analysis of 5,265 scRNA-seq profiles, we identified 18 unique cell populations. Combining mass cytometry and transcriptomics revealed cell states expanded in RA synovia: THY1(CD90)HLA-DRA sublining fibroblasts, IL1B pro-inflammatory monocytes, ITGAXTBX21 autoimmune-associated B cells and PDCD1 peripheral helper T (T) cells and follicular helper T (T) cells. We defined distinct subsets of CD8 T cells characterized by GZMK, GZMB, and GNLY phenotypes. We mapped inflammatory mediators to their source cell populations; for example, we attributed IL6 expression to THY1HLA-DRA fibroblasts and IL1B production to pro-inflammatory monocytes. These populations are potentially key mediators of RA pathogenesis.
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http://dx.doi.org/10.1038/s41590-019-0378-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6602051PMC
July 2019

Altered monocyte and NK cell phenotypes correlate with posttrauma infection.

J Trauma Acute Care Surg 2019 08;87(2):337-341

From the Department of Surgery, Brigham and Women's Hospital and Harvard Medical School (A.S., B.K.Y., M.G., J.K., J.P.N., W.L., Y.N., T.W., A.S., R.A., J.A.L.); Boston, Massachusetts; Department of Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School (G.A.B. C.H.), Boston, MA.

Background: Trauma induces a complex immune response, requiring a systems biology approach to capture multicellular changes. Using mass cytometry by time-of-flight (CyTOF), we evaluated time-dependent changes in peripheral blood in trauma patients to identify changes correlated with infection.

Methods: Total leukocytes were prepared via red blood cell lysis using peripheral blood samples from trauma patients with an Injury Severity Score greater than 20 at Days 1, 3, and 5 after injury, and from age- and sex-matched uninjured controls. Cells were stained using a 33-marker immunophenotyping CyTOF panel. Statistics were calculated using one-way analysis of variance with multiple comparisons.

Results: The CyTOF staining demonstrated changes in many cell subsets. The mean expression intensity of CD86 on monocytes decreased significantly at all time points after injury. When the patients were stratified based on development of infection, there was a trend to decreased CD86 expression on monocytes of those patients that developed subsequent infection. Based on stratification, we identified significantly increased expression of CD39 on NK cells only in patients that developed an infection.

Conclusion: This study used a systems biology approach to identify novel changes in circulating immune cell subsets in trauma patients correlating with post-traumatic infection. Decreased expression of CD86, a costimulatory molecule, on monocytes demonstrates that trauma affects the innate system's ability to control T-cell immunity. We also found that CD39 expression on NK cells increased significantly in patients with subsequent infection. CD39 is a protein that generates adenosine, which has immunosuppressive effects on several immune cell types including NK cells. In summary, our results point to pathways that may be central to second-hit infections and further study to delineate these pathways could be key to generating clinical biomarkers or targeted immune therapies for trauma patients.

Level Of Evidence: Prognostic study, level II.
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http://dx.doi.org/10.1097/TA.0000000000002264DOI Listing
August 2019

Mixed-effects association of single cells identifies an expanded effector CD4 T cell subset in rheumatoid arthritis.

Sci Transl Med 2018 10;10(463)

Center for Data Sciences, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.

High-dimensional single-cell analyses have improved the ability to resolve complex mixtures of cells from human disease samples; however, identifying disease-associated cell types or cell states in patient samples remains challenging because of technical and interindividual variation. Here, we present mixed-effects modeling of associations of single cells (MASC), a reverse single-cell association strategy for testing whether case-control status influences the membership of single cells in any of multiple cellular subsets while accounting for technical confounders and biological variation. Applying MASC to mass cytometry analyses of CD4 T cells from the blood of rheumatoid arthritis (RA) patients and controls revealed a significantly expanded population of CD4 T cells, identified as CD27 HLA-DR effector memory cells, in RA patients (odds ratio, 1.7; = 1.1 × 10). The frequency of CD27 HLA-DR cells was similarly elevated in blood samples from a second RA patient cohort, and CD27 HLA-DR cell frequency decreased in RA patients who responded to immunosuppressive therapy. Mass cytometry and flow cytometry analyses indicated that CD27 HLA-DR cells were associated with RA (meta-analysis = 2.3 × 10). Compared to peripheral blood, synovial fluid and synovial tissue samples from RA patients contained about fivefold higher frequencies of CD27 HLA-DR cells, which comprised ~10% of synovial CD4 T cells. CD27 HLA-DR cells expressed a distinctive effector memory transcriptomic program with T helper 1 (T1)- and cytotoxicity-associated features and produced abundant interferon-γ (IFN-γ) and granzyme A protein upon stimulation. We propose that MASC is a broadly applicable method to identify disease-associated cell populations in high-dimensional single-cell data.
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http://dx.doi.org/10.1126/scitranslmed.aaq0305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6448773PMC
October 2018

Methods for high-dimensional analysis of cells dissociated from cryopreserved synovial tissue

Arthritis Res Ther 2018 07 11;20(1):139. Epub 2018 Jul 11.

Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.

Background: Detailed molecular analyses of cells from rheumatoid arthritis (RA) synovium hold promise in identifying cellular phenotypes that drive tissue pathology and joint damage. The Accelerating Medicines Partnership RA/SLE Network aims to deconstruct autoimmune pathology by examining cells within target tissues through multiple high-dimensional assays. Robust standardized protocols need to be developed before cellular phenotypes at a single cell level can be effectively compared across patient samples.

Methods: Multiple clinical sites collected cryopreserved synovial tissue fragments from arthroplasty and synovial biopsy in a 10% DMSO solution. Mechanical and enzymatic dissociation parameters were optimized for viable cell extraction and surface protein preservation for cell sorting and mass cytometry, as well as for reproducibility in RNA sequencing (RNA-seq). Cryopreserved synovial samples were collectively analyzed at a central processing site by a custom-designed and validated 35-marker mass cytometry panel. In parallel, each sample was flow sorted into fibroblast, T-cell, B-cell, and macrophage suspensions for bulk population RNA-seq and plate-based single-cell CEL-Seq2 RNA-seq.

Results: Upon dissociation, cryopreserved synovial tissue fragments yielded a high frequency of viable cells, comparable to samples undergoing immediate processing. Optimization of synovial tissue dissociation across six clinical collection sites with ~ 30 arthroplasty and ~ 20 biopsy samples yielded a consensus digestion protocol using 100 μg/ml of Liberase™ TL enzyme preparation. This protocol yielded immune and stromal cell lineages with preserved surface markers and minimized variability across replicate RNA-seq transcriptomes. Mass cytometry analysis of cells from cryopreserved synovium distinguished diverse fibroblast phenotypes, distinct populations of memory B cells and antibody-secreting cells, and multiple CD4 and CD8 T-cell activation states. Bulk RNA-seq of sorted cell populations demonstrated robust separation of synovial lymphocytes, fibroblasts, and macrophages. Single-cell RNA-seq produced transcriptomes of over 1000 genes/cell, including transcripts encoding characteristic lineage markers identified.

Conclusions: We have established a robust protocol to acquire viable cells from cryopreserved synovial tissue with intact transcriptomes and cell surface phenotypes. A centralized pipeline to generate multiple high-dimensional analyses of synovial tissue samples collected across a collaborative network was developed. Integrated analysis of such datasets from large patient cohorts may help define molecular heterogeneity within RA pathology and identify new therapeutic targets and biomarkers.
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http://dx.doi.org/10.1186/s13075-018-1631-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6042350PMC
July 2018

Frontline Science: Targeted expression of a dominant-negative high mobility group A1 transgene improves outcome in sepsis.

J Leukoc Biol 2018 10 5;104(4):677-689. Epub 2018 Jul 5.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.

High mobility group (HMG) proteins are a family of architectural transcription factors, with HMGA1 playing a role in the regulation of genes involved in promoting systemic inflammatory responses. We speculated that blocking HMGA1-mediated pathways might improve outcomes from sepsis. To investigate HMGA1 further, we developed genetically modified mice expressing a dominant negative (dn) form of HMGA1 targeted to the vasculature. In dnHMGA1 transgenic (Tg) mice, endogenous HMGA1 is present, but its function is decreased due to the mutant transgene. These mice allowed us to specifically study the importance of HMGA1 not only during a purely pro-inflammatory insult of endotoxemia, but also during microbial sepsis induced by implantation of a bacterial-laden fibrin clot into the peritoneum. We found that the dnHMGA1 transgene was only present in Tg and not wild-type (WT) littermate mice, and the mutant transgene was able to interact with transcription factors (such as NF-κB), but was not able to bind DNA. Tg mice exhibited a blunted hypotensive response to endotoxemia, and less mortality in microbial sepsis. Moreover, Tg mice had a reduced inflammatory response during sepsis, with decreased macrophage and neutrophil infiltration into tissues, which was associated with reduced expression of monocyte chemotactic protein-1 and macrophage inflammatory protein-2. Collectively, these data suggest that targeted expression of a dnHMGA1 transgene is able to improve outcomes in models of endotoxin exposure and microbial sepsis, in part by modulating the immune response and suggest a novel modifiable pathway to target therapeutics in sepsis.
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http://dx.doi.org/10.1002/JLB.4HI0817-333RRDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431081PMC
October 2018

Purinergic P2X4 receptors and mitochondrial ATP production regulate T cell migration.

J Clin Invest 2018 08 23;128(8):3583-3594. Epub 2018 Jul 23.

Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.

T cells must migrate in order to encounter antigen-presenting cells (APCs) and to execute their varied functions in immune defense and inflammation. ATP release and autocrine signaling through purinergic receptors contribute to T cell activation at the immune synapse that T cells form with APCs. Here, we show that T cells also require ATP release and purinergic signaling for their migration to APCs. We found that the chemokine stromal-derived factor-1α (SDF-1α) triggered mitochondrial ATP production, rapid bursts of ATP release, and increased migration of primary human CD4+ T cells. This process depended on pannexin-1 ATP release channels and autocrine stimulation of P2X4 receptors. SDF-1α stimulation caused localized accumulation of mitochondria with P2X4 receptors near the front of cells, resulting in a feed-forward signaling mechanism that promotes cellular Ca2+ influx and sustains mitochondrial ATP synthesis at levels needed for pseudopod protrusion, T cell polarization, and cell migration. Inhibition of P2X4 receptors blocked the activation and migration of T cells in vitro. In a mouse lung transplant model, P2X4 receptor antagonist treatment prevented the recruitment of T cells into allograft tissue and the rejection of lung transplants. Our findings suggest that P2X4 receptors are therapeutic targets for immunomodulation in transplantation and inflammatory diseases.
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http://dx.doi.org/10.1172/JCI120972DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6063471PMC
August 2018

Functionally distinct disease-associated fibroblast subsets in rheumatoid arthritis.

Nat Commun 2018 02 23;9(1):789. Epub 2018 Feb 23.

Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.

Fibroblasts regulate tissue homeostasis, coordinate inflammatory responses, and mediate tissue damage. In rheumatoid arthritis (RA), synovial fibroblasts maintain chronic inflammation which leads to joint destruction. Little is known about fibroblast heterogeneity or if aberrations in fibroblast subsets relate to pathology. Here, we show functional and transcriptional differences between fibroblast subsets from human synovial tissues using bulk transcriptomics of targeted subpopulations and single-cell transcriptomics. We identify seven fibroblast subsets with distinct surface protein phenotypes, and collapse them into three subsets by integrating transcriptomic data. One fibroblast subset, characterized by the expression of proteins podoplanin, THY1 membrane glycoprotein and cadherin-11, but lacking CD34, is threefold expanded in patients with RA relative to patients with osteoarthritis. These fibroblasts localize to the perivascular zone in inflamed synovium, secrete proinflammatory cytokines, are proliferative, and have an in vitro phenotype characteristic of invasive cells. Our strategy may be used as a template to identify pathogenic stromal cellular subsets in other complex diseases.
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http://dx.doi.org/10.1038/s41467-018-02892-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5824882PMC
February 2018

Phenotyping the Immune Response to Trauma: A Multiparametric Systems Immunology Approach.

Crit Care Med 2017 Sep;45(9):1523-1530

All authors: Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.

Objective: Trauma induces a complex immune response that requires a systems biology research approach. Here, we used a novel technology, mass cytometry by time-of-flight, to comprehensively characterize the multicellular response to trauma.

Design: Peripheral blood mononuclear cells samples were stained with a 38-marker immunophenotyping cytometry by time-of-flight panel. Separately, matched peripheral blood mononuclear cells were stimulated in vitro with heat-killed Streptococcus pneumoniae or CD3/CD28 antibodies and stained with a 38-marker cytokine panel. Monocytes were studied for phagocytosis and oxidative burst.

Setting: Single-institution level 1 trauma center.

Patients Or Subjects: Trauma patients with injury severity scores greater than 20 (n = 10) at days 1, 3, and 5 after injury, and age- and gender-matched controls.

Interventions: None.

Measurements And Main Results: Trauma-induced expansion of Th17-type CD4 T cells was seen with increased expression of interleukin-17 and interleukin-22 by day 5 after injury. Natural killer cells showed reduced T-bet expression at day 1 with an associated decrease in tumor necrosis factor-β, interferon-γ, and monocyte chemoattractant protein-1. Monocytes showed robust expansion following trauma but displayed decreased stimulated proinflammatory cytokine production and significantly reduced human leukocyte antigen - antigen D related expression. Further analysis of trauma-induced monocytes indicated that phagocytosis was no different from controls. However, monocyte oxidative burst after stimulation increased significantly after injury.

Conclusions: Using cytometry by time-of-flight, we were able to identify several major time-dependent phenotypic changes in blood immune cell subsets that occur following trauma, including induction of Th17-type CD4 T cells, reduced T-bet expression by natural killer cells, and expansion of blood monocytes with less proinflammatory cytokine response to bacterial stimulation and less human leukocyte antigen - antigen D related. We hypothesized that monocyte function might be suppressed after injury. However, monocyte phagocytosis was normal and oxidative burst was augmented, suggesting that their innate antimicrobial functions were preserved. Future studies will better characterize the cell subsets identified as being significantly altered by trauma using cytometry by time-of-flight, RNAseq technology, and functional studies.
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http://dx.doi.org/10.1097/CCM.0000000000002577DOI Listing
September 2017

Pathologically expanded peripheral T helper cell subset drives B cells in rheumatoid arthritis.

Nature 2017 02;542(7639):110-114

Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.

CD4 T cells are central mediators of autoimmune pathology; however, defining their key effector functions in specific autoimmune diseases remains challenging. Pathogenic CD4 T cells within affected tissues may be identified by expression of markers of recent activation. Here we use mass cytometry to analyse activated T cells in joint tissue from patients with rheumatoid arthritis, a chronic immune-mediated arthritis that affects up to 1% of the population. This approach revealed a markedly expanded population of PD-1CXCR5CD4 T cells in synovium of patients with rheumatoid arthritis. However, these cells are not exhausted, despite high PD-1 expression. Rather, using multidimensional cytometry, transcriptomics, and functional assays, we define a population of PD-1CXCR5 'peripheral helper' T (T) cells that express factors enabling B-cell help, including IL-21, CXCL13, ICOS, and MAF. Like PD-1CXCR5 T follicular helper cells, T cells induce plasma cell differentiation in vitro through IL-21 secretion and SLAMF5 interaction (refs 3, 4). However, global transcriptomics highlight differences between T cells and T follicular helper cells, including altered expression of BCL6 and BLIMP1 and unique expression of chemokine receptors that direct migration to inflamed sites, such as CCR2, CX3CR1, and CCR5, in T cells. T cells appear to be uniquely poised to promote B-cell responses and antibody production within pathologically inflamed non-lymphoid tissues.
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http://dx.doi.org/10.1038/nature20810DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349321PMC
February 2017

Efficacy of Antibody to PNAG Against Keratitis Caused by Fungal Pathogens.

Invest Ophthalmol Vis Sci 2016 12;57(15):6797-6804

Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States.

Purpose: Developing immunotherapies for fungal eye infections is a high priority. We analyzed fungal pathogens for expression of the surface polysaccharide, poly-N-acetyl glucosamine (PNAG), and used a mouse model of ocular keratitis caused by Aspergillus flavus, A. fumigatus, or Fusarium solani to determine if PNAG was an immunotherapy target and requirements for ancillary cellular and molecular immune effectors.

Methods: Enzyme-linked immunosorbent assay (ELISA) or immunofluorescence was used to detect PNAG on fungal cells. Keratitis was induced by scratching corneas of C57BL/6, IL-17R KO, RAG-1 KO, or IL-22 KO mice followed by inoculation with fungal pathogens. Goat antibodies to PNAG, a PNAG-specific human IgG1 monoclonal antibody, or control antibodies were injected either prophylactically plus therapeutically or therapeutically only, and corneal pathology and fungal levels determined in infected eyes at 24 or 48 hours after infection.

Results: All tested fungal species produced PNAG. Prophylactic or therapeutic treatment by intraperitoneal (IP) injection of antibody to PNAG combined with post-infection topical application of antibody, the latter also used for A. fumigatus, led to reduced fungal levels, corneal pathology, and cytokine expression. Topical administration only of the PNAG monoclonal antibodies (MAb) reduced fungal loads and corneal pathology. There was no antibody protection in IL-17R KO, RAG-1 KO, or IL-22 KO mice.

Conclusions: Poly-N-acetyl glucosamine is produced by clinically important fungal ocular pathogens. Antibody to PNAG demonstrated protection against Aspergillus and Fusarium keratitis, requiring T cells producing IL-17 and IL-22. These findings indicate the potential to prevent or treat fungal infections by vaccines and immunotherapeutics to PNAG.
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http://dx.doi.org/10.1167/iovs.16-20358DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5215555PMC
December 2016

The CD4/CD8 ratio is associated with coronary artery disease (CAD) in elderly Chinese patients.

Int Immunopharmacol 2017 Jan 17;42:39-43. Epub 2016 Nov 17.

Department of Geriatrics, The First Affiliated Hospital to Third Military Medical University, Southwest Hospital, Chongqing, China. Electronic address:

Objective: The aim of this study was to investigate the relationship between number of circulating T cells and coronary artery disease (CAD) in an elderly Chinese population.

Methods: A total of 295 elderly inpatients (age≥60) were included in this cross-sectional study. Their clinical and biochemical characteristics were recorded. Patients were divided to two groups: control patients and CAD patients. The risk factors of CAD were explored by binary logistic regression analysis.

Results: Compared with control patients, the ratio of CD4 to CD8 T cells was significantly increased in CAD patients. There was no difference in the number of CD3, CD4, and CD8 T cells between the two groups. Multiple logistic regression analysis showed that CAD was independently associated with age, gender, body mass index (BMI), systolic blood pressure (SBP), chronic heart failure (CHF) and the CD4/CD8 ratio. In addition, after adjusting for different clinical parameters (including gender, age, CHF, hypertension, arrhythmia, SBP, and BMI), the risk of CAD was significantly increased in patients with a CD4/CD8 ratio>1.5.

Conclusions: There was a strong and independent association between the ratio of CD4/CD8 and CAD in elderly Chinese population.
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http://dx.doi.org/10.1016/j.intimp.2016.11.007DOI Listing
January 2017

Beneficial Effects of CpG-Oligodeoxynucleotide Treatment on Trauma and Secondary Lung Infection.

J Immunol 2016 Jan 16;196(2):767-77. Epub 2015 Dec 16.

Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115;

Although Streptococcus pneumoniae is usually found as a commensal in healthy individuals, it can act as a pathogen in trauma patients, causing such complications as early-onset pneumonia and sepsis. We discovered that treating mice with an A-class CpG-oligodeoxynucleotide (ODN) at 2 h after traumatic injury significantly improved mouse survival following early-onset secondary lung infection with S. pneumoniae. This study used mass cytometry (cytometry by time-of-flight) and Luminex technologies to characterize the cellular immune response to secondary S. pneumoniae lung infection at 1 and 3 d postinfection. We found increased expression of CD14, CD64, and PD-L1 on F4-80(+) and F4-80(+)CD11c(+) macrophages, CD11c(+) dendritic cells, and CD14(+)CD172a(+) cells after burn-injury and infection, supporting previous reports of innate immune cell activation in sepsis. CpG-ODN treatment at 2 h after burn-injury reversed these effects; improved pathogen clearance; and led to an increased expression of CD25, CD27, MHCII, and IL-17 on or in TCRγδ cells at 1 d postinfection. At 3 d postinfection, CpG-ODN treatment increased the expression of PD-L1 on innate cell subsets. Furthermore, we analyzed cytokine levels in lung-washout samples of TCRγδ cell-depleted (TCRγδ(-)) mice to demonstrate that the effects of CpG-ODN on cytokine expression after burn-injury and S. pneumoniae infection rely on functional TCRγδ cells. In summary, we demonstrate that cytometry by time-of-flight provides an effective strategy to systematically identify specific cellular phenotypic responses to trauma and bacterial pneumonia and to discover changes in immune system phenotypes associated with beneficial immunotherapy.
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http://dx.doi.org/10.4049/jimmunol.1500597DOI Listing
January 2016

Expansion of CD25+ Innate Lymphoid Cells Reduces Atherosclerosis.

Arterioscler Thromb Vasc Biol 2015 Dec 22;35(12):2526-35. Epub 2015 Oct 22.

From the Departments of Pathology (D.E., A.C.F., N.A.-G., F.K., T.C., P.J., N.G., A.H.L.) and Surgery (J.A.L.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA.

Objective: Innate lymphoid cells (ILCs) are a newly discovered subset of immune cells that promote tissue homeostasis and protect against pathogens. ILCs produce cytokines also produced by T lymphocytes that have been shown to affect atherosclerosis, but the influence of ILCs on atherosclerosis has not been explored.

Approach And Results: We demonstrate that CD25(+) ILCs that produce type 2 cytokines (ILC2s) are present in the aorta of atherosclerotic immunodeficient ldlr(-/-)rag1(-/-) mice. To investigate the role of ILCs in atherosclerosis, ldlr(-/-)rag1(-/-) mice were concurrently fed an atherogenic diet and treated with either ILC-depleting anti-CD90.2 antibodies or IL-2/anti-IL-2 complexes that expand CD25(+) ILCs. Lesion development was not affected by anti-CD90.2 treatment, but was reduced in IL-2/anti-IL-2-treated mice. These IL-2-treated mice had reduced very low-density lipoprotein cholesterol and increased triglycerides compared with controls and reduced apolipoprotein B100 gene expression in the liver. IL-2/anti-IL-2 treatment caused expansion of ILC2s in aorta and other tissues, elevated levels of IL-5, systemic eosinophila, and hepatic eosinophilic inflammation. Blockade of IL-5 reversed the IL-2 complex-induced eosinophilia but did not change lesion size.

Conclusions: This study demonstrates that expansion of CD25-expressing ILCs by IL-2/anti-IL-2 complexes leads to a reduction in very low-density lipoprotein cholesterol and atherosclerosis. Global depletion of ILCs by anti-CD90.2 did not significantly affect lesion size indicating that different ILC subsets may have divergent effects on atherosclerosis.
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http://dx.doi.org/10.1161/ATVBAHA.115.306048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4717486PMC
December 2015

Characterization of lung infection-induced TCRγδ T cell phenotypes by CyTOF mass cytometry.

J Leukoc Biol 2016 Mar 1;99(3):483-93. Epub 2015 Oct 1.

*Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA; and Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany

T cell receptor γδ cells are known to be the primary effector T cells involved in the response to bacterial infections, yet their phenotypic characteristics are not as well established as other T cell subsets. In this study, we used cytometry by time-of-flight mass cytometry to better characterize the phenotypic response of T cell receptor γδ cells to Streptococcus pneumoniae lung infection. Mice were infected, and cells from lung washouts, spleen, and lymph nodes were stained to detect cell-surface, intracellular, and signaling markers. We observed that infection caused a significant increase in T cell receptor γδ cells, which expressed high interferon-γ and interleukin-17A levels. Profiling T cell receptor γδ cells by cytometry by time-of-flight revealed that activated γδ T cells uniquely coexpressed cell-surface Gr-1, cluster of differentiation 14, and cluster of differentiation 274 (programmed death-ligand 1). Further classification of Gr-1 expression patterns on T cell receptor γδ cells demonstrated that Gr-1(+) T cell receptor γδ cells were the primary source of interferon-γ, whereas Gr-1(-) cells mostly expressed interleukin-17A. Gr-1(+) T cell receptor γδ cells also showed higher ζ-chain-associated protein kinase 70, p38, and 4eBP1 signaling in response to infection as compared with Gr-1(-) T cell receptor γδ cells. Taken together, Gr-1 expression patterns on γδ T cells in the lung provide a robust marker to differentiate interferon-γ- and interleukin-17A-producing subsets involved in the early immune response to bacterial pneumonia.
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http://dx.doi.org/10.1189/jlb.4A0315-115RRDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6608043PMC
March 2016

Response to comment on "Radiation exposure induces inflammasome pathway activation in immune cells".

Authors:
James A Lederer

J Immunol 2015 Jun;194(11):5039

Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, MA 02115

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http://dx.doi.org/10.4049/jimmunol.1500789DOI Listing
June 2015