Infectious disease
Abstract
Most of the patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mount a humoral immune response to the virus within a few weeks of infection, but the duration of this response and how it correlates with clinical outcomes has not been completely characterized. Of particular importance is the identification of immune correlates of infection that would support public health decision-making on treatment approaches, vaccination strategies, and convalescent plasma therapy. While ELISA-based assays to detect and quantitate antibodies to SARS-CoV-2 in patient samples have been developed, the detection of neutralizing antibodies typically requires more demanding cell-based viral assays. Here, we present a safe and efficient protein-based assay for the detection of serum and plasma antibodies that block the interaction of the SARS-CoV-2 spike protein receptor binding domain (RBD) with its receptor, angiotensin converting-enzyme 2 (ACE2). The assay serves as a surrogate neutralization assay and is performed on the same platform and in parallel with an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against the RBD, enabling a direct comparison. The results obtained with our assay correlate with those of two viral based assays, a plaque reduction neutralization test (PRNT) that uses live SARS-CoV-2 virus, and a spike pseudotyped viral-vector-based assay.
Authors
Kento T. Abe, Zhijie Li, Reuben Samson, Payman Samavarchi-Tehrani, Emelissa J. Valcourt, Heidi Wood, Patrick Budylowski, Alan P. Dupuis II, Roxie C. Girardin, Bhavisha Rathod, Jenny Wang, Miriam Barrios-Rodiles, Karen Colwill, Allison McGeer, Samira Mubareka, Jennifer L. Gommerman, Yves Durocher, Mario Ostrowski, Kathleen A. McDonough, Michael A. Drebot, Steven J. Drews, James M. Rini, Anne-Claude Gingras
Abstract
The emergence of SARS-CoV-2 has created an international health crisis. Small animal models mirroring SARS-CoV-2 human disease are essential for medical countermeasure (MCM) development. Mice are refractory to SARS-CoV-2 infection due to low affinity binding to the murine angiotensin-converting enzyme 2 (ACE2) protein. Here we evaluated the pathogenesis of SARS-CoV-2 in male and female mice expressing the human ACE2 gene under the control of the keratin 18 promotor. In contrast to non-transgenic mice, intranasal exposure of K18-hACE2 animals to two different doses of SARS-CoV-2 resulted in acute disease including weight loss, lung injury, brain infection and lethality. Vasculitis was the most prominent finding in the lungs of infected mice. Transcriptomic analysis from lungs of infected animals revealed increases in transcripts involved in lung injury and inflammatory cytokines. In the lower dose challenge groups, there was a survival advantage in the female mice with 60% surviving infection whereas all male mice succumbed to disease. Male mice that succumbed to disease had higher levels of inflammatory transcripts compared to female mice. This is the first highly lethal murine infection model for SARS-CoV-2. The K18-hACE2 murine model will be valuable for the study of SARS-CoV-2 pathogenesis and the assessment of MCMs.
Authors
Joseph W. Golden, Curtis R. Cline, Xiankun Zeng, Aura R. Garrison, Brian D. Carey, Eric M. Mucker, Lauren E. White, Joshua D. Shamblin, Rebecca L. Brocato, Jun Liu, April M. Babka, Hypaitia B. Rauch, Jeffrey M. Smith, Bradley S. Hollidge, Collin Fitzpatrick, Catherine V. Badger, Jay W. Hooper
Abstract
Background: Control of the tuberculosis (TB) pandemic remains hindered, in part, by a lack of simple and accurate measures of treatment efficacy. Current gold standard markers rely on sputum-based assays that are slow and challenging to implement. Previous work identified urinary N1, N12-diacetylspermine (DiAcSpm), neopterin, hydroxykynurenine, N-acetylhexosamine, ureidopropionic acid, sialic acid, and m/z 241.0903 as potential biomarkers of active pulmonary TB (ATB). Here, we evaluated their ability to serve as biomarkers of TB treatment response and mycobacterial load. Methods: We analyzed urine samples prospectively collected from two cohorts with ATB: 34 participants from African countries treated with first line TB therapy (HRZE) and followed for one year, and 35 participants from Haiti treated with either HRZE or an experimental drug followed for 14 days. Blinded samples were analyzed by untargeted high-performance liquid chromatography-coupled-time of flight-mass spectrometry. Results: Urinary levels of all seven molecules exhibited significant decreases by week 26 of successful treatment (p=0.01-p<0.0001), and positive correlations with sputum mycobacterial load (p<0.0001). Urinary levels of DiAcSpm exhibited significant decreases in participants treated with HRZE as early as 14 days (p<0.0001) but were unchanged in participants receiving ineffective therapy (p=0.14). Conclusion: Reductions in urinary DiAcSpm, neopterin, hydroxykynurenine, N-acetylhexosamine, ureidopropionic acid, sialic acid, and m/z 241.0903 correlated with successful anti-TB treatment and sputum mycobacterial load. Levels of DiAcSpm exhibited reductions capable of differentiating treatment success from failure as early as two weeks after the initiation of chemotherapy, commending its further development as a potentially simple, non-invasive biomarker of treatment response and bacterial load. Funding: This work was supported by the Clinical and Translational Science Center at Weill Cornell College of Medicine (NIH/NCATS 1 UL1 TR002384-02 and KL2TR000458), the Department of Defense (PR170782), the National Institute of Allergy and Infectious Disease grants (NIAID T32AI007613-16, K24 AI098627 and K23 AI131913), the NIH Fogarty International Center grants (R24 TW007988 and TW010062), the National Institute of Health grant (R01 GM135926 ), the Abby and Howard P. Milstein Program in Chemical Biology and Translational Medicine, and the Tuberculosis Research Units Networks (TBRU-N, AI111143).
Authors
Qianjing Xia, Myung Hee Lee, Kathleen F. Walsh, Kathrine McAulay, James M. Bean, Daniel W. Fitzgerald, Kathryn M. Dupnik, Warren D. Johnson, Jean W. Pape, Kyu Y. Rhee, Flonza Isa
Abstract
Background Tuberculosis (TB) kills more people than any other infection and new diagnostic tests to identify active cases are urgently required. We aimed to discover and verify novel markers for TB in non-depleted plasma. Methods We applied an optimised quantitative proteomics discovery methodology based on multidimensional and orthogonal liquid chromatographic separation hyphenated with high-resolution mass spectrometry (q3D LC-MS) to study non-depleted plasma of 11 patients with active TB compared to 10 healthy control donors. Prioritised candidates were verified in an independent UK-based (n=118) and a South African cohorts (n=203). Results We generated the most comprehensive TB plasma proteome to date, profiling 5022 proteins spanning 11 orders-of-magnitude concentration range with diverse biochemical and molecular properties. We further analysed the predominantly low molecular weight sub-proteome; identifying 46 proteins with significantly increased and 90 with decreased abundance (peptide FDR ≤1%, q-value ≤0.05). Biological network analysis showed regulation of new pathways involving lipid and organophosphate ester transport. Verification was performed for novel candidate biomarkers (CFHR5, ILF2) in two independent cohorts. These proteins were elevated in both TB and other respiratory diseases (ORD). Receiver-operating-characteristics analyses using a 5-protein panel (CFHR5, LRG1, CRP, LBP and SAA1) exhibited discriminatory power in distinguishing between TB and ORD (AUC =0.81). Conclusions We report the most comprehensive TB plasma proteome to date, identifying numerous novel markers with verification in two independent cohorts, which led to a 5-protein biosignature with potential to improve TB diagnosis. With further development, these biomarkers have potential as a diagnostic triage test. Funding Colombia: Colciencias. UK: Medical Research Council, Innovate UK, National Institute for Health Research, Academy of Medical Sciences. Peru: Program for Advanced Research Capacities for AIDS. South Africa: Wellcome Centre for Infectious Diseases Research.
Authors
Diana J. Garay-Baquero, Cory H. White, Naomi F. Walker, Marc Tebruegge, Hannah F. Schiff, Cesar Ugarte-Gil, Stephen Morris-Jones, Ben G. Marshall, Antigoni Manousopoulou, John H. Adamson, Andres F. Vallejo, Magdalena K. Bielecka, Robert J. Wilkinson, Liku B. Tezera, Christopher H. Woelk, Spiros D. Garbis, Paul Elkington
Abstract
Clostridioides difficile is a leading cause of nosocomial infection responsible for significant morbidity and mortality with limited options for therapy. Secreted C. difficile toxin B (TcdB) is a major contributor to disease pathology and select TcdB-specific Abs may protect against disease recurrence. However, the high frequency of recurrence suggests that the memory B cell response, essential for new Ab production following C. difficile re-exposure, is insufficient. We therefore isolated TcdB-specific memory B cells from individuals with a history of C. difficile infection and performed single-cell deep sequencing of their Ab genes. Herein, we report that TcdB-specific memory B cell-encoded antibodies showed somatic hypermutation but displayed limited isotype class switch. Memory B cell-encoded monoclonal antibodies generated from the gene sequences revealed low to moderate affinity for TcdB and a limited ability to neutralize TcdB. These findings indicate that memory B cells are an important factor in C. difficile disease recurrence.
Authors
Hemangi B. Shah, Kenneth Smith, Edgar J. Scott, II, Jason L. Larabee, Judith A. James, Jimmy D. Ballard, Mark L. Lang
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a novel tick-borne bunyavirus that recently emerged in East Asian countries. SFTS is characterized by high fever, thrombocytopenia, leukopenia, multiorgan failure, and hemorrhage with case fatality rates of 6.3% to 30%. Neither antivirals nor vaccines are available at present. We previously demonstrated that neutralizing antibodies specific for SFTSV glycoprotein (Gn) played a vital role in the survival of patients with SFTS. Nanobodies from camels present unique properties, such as thermostability, high affinity, and low immunogenicity. In the current study, mammalian expressed SFTSV Gn was used to immunize a camel, and functional nanobodies were isolated from the B cell nanobody library constructed from the immunized animal. Clone SNB02 was selected for in-depth analysis for its inhibition of SFTSV replication both in vitro and in vivo. We showed that SNB02 potently inhibited SFTSV infection and prevented thrombocytopenia in a humanized mouse model and is a potential candidate for therapeutics.
Authors
Xilin Wu, Yanlei Li, Bilian Huang, Xiaohua Ma, Linjing Zhu, Nan Zheng, Shijie Xu, Waqas Nawaz, Changping Xu, Zhiwei Wu
Abstract
Critical illness is accompanied by the release of large amounts of the anaphylotoxin, C5a. C5a suppresses antimicrobial functions of neutrophils which is associated with adverse outcomes. The signalling pathways that mediate C5a-induced neutrophil dysfunction are incompletely understood. Healthy donor neutrophils exposed to purified C5a demonstrated a prolonged defect (7 hours) in phagocytosis of Staphylococcus aureus. Phosphoproteomic profiling of 2712 phosphoproteins identified persistent C5a signalling and selective impairment of phagosomal protein phosphorylation on exposure to S. aureus. Notable proteins included early endosomal marker ZFYVE16 and V-ATPase proton channel component ATPV1G1. A novel assay of phagosomal acidification demonstrated C5a-induced impairment of phagosomal acidification which was recapitulated in neutrophils from critically ill patients. Examination of the C5a-impaired protein phosphorylation indicated a role for the phosphatidylinositol 3-kinase VPS34 in phagosomal maturation. Inhibition of VPS34 impaired neutrophil phagosomal acidification and killing of S. aureus. This study provides a phosphoproteomic assessment of human neutrophil signalling in response to S. aureus and its disruption by C5a, identifying a defect in phagosomal maturation and new mechanisms of immune failure in critical illness.
Authors
Alexander J.T. Wood, Arlette M. Vassallo, Marie-Helene Ruchaud-Sparagano, Jonathan Scott, Carmelo Zinnato, Carmen Gonzalez-Tejedo, Kamal Kishore, Clive S. D’Santos, A. John Simpson, David K. Menon, Charlotte Summers, Edwin R. Chilvers, Klaus Okkenhaug, Andrew Conway Morris
Abstract
Arrestin domain containing 3 (ARRDC3) represents a newly discovered α-arrestin involved in obesity, inflammation and cancer. Here we demonstrated a pro-inflammation role of ARRDC3 in H. pylori-associated gastritis. Increased ARRDC3 was detected in gastric mucosa of patients and mice infected with H. pylori. ARRDC3 in gastric epithelial cells (GECs) was induced by H. pylori, regulated by ERK and PI3K-AKT pathways in a cagA-dependent manner. Human gastric ARRDC3 correlated with the severity of gastritis, and mouse ARRDC3 from non-BM-derived cells promoted gastric inflammation. This inflammation was characterized by the CXCR2-dependent influx of CD45+CD11b+Ly6C-Ly6G+ neutrophils, whose migration was induced via the ARRDC3-dependent production of CXCL2 by GECs. Importantly, gastric inflammation was attenuated in ARRDC3-/- mice but increased in protease-activated receptor 1 (PAR1)-/- mice. Mechanistically, ARRDC3 in GECs directly interacted with PAR1 and negatively regulated PAR1 via ARRDC3-mediated lysosomal degradation, which abrogated the suppression of CXCL2 production and following neutrophil chemotaxis by PAR1, thereby contributing to the development of H. pylori-associated gastritis. This study identifies a novel regulatory network involving H. pylori, GECs, ARRDC3, PAR1, and neutrophils, which collectively exert a pro-inflammatory effect within gastric microenvironment. Efforts to inhibit this ARRDC3-dependent pathway may prove valuable strategies in treating of H. pylori-associated gastritis.
Authors
Yu-gang Liu, Yong-sheng Teng, Zhi-guo Shan, Ping Cheng, Chuan-jie Hao, Yi-pin Lv, Fang-yuan Mao, Shi-ming Yang, Weisan Chen, Yong-Liang Zhao, Nan You, Quan-ming Zou, Yuan Zhuang
Abstract
BACKGROUND Prediction of adverse outcomes in cerebral malaria (CM) is difficult. We hypothesized that cell-free DNA (cfDNA) levels would facilitate identification of severe and potentially fatal CM cases.METHODS In this retrospective study, plasma from Malawian children with CM (n = 134), uncomplicated malaria (UM, n = 77), and healthy controls (HC, n = 60) was assayed for cfDNA using a fluorescence assay. Host and parasite cfDNA was measured by quantitative PCR. Immune markers were determined by ELISA, Luminex, or cytometric bead array.RESULTS Total cfDNA increased with malaria severity (HC versus UM, P < 0.001; HC versus CM, P < 0.0001; UM versus CM, P < 0.0001), was elevated in retinopathy-positive (Ret+) CM relative to Ret– CM (7.66 versus 5.47 ng/μL, P = 0.027), and differentiated Ret+ fatal cases from survivors (AUC 0.779; P < 0.001). cfDNA levels in patients with non–malarial febrile illness (NMF, P = 0.25) and non–malarial coma (NMC, P = 0.99) were comparable with UM. Host DNA, rather than parasite DNA, was the major cfDNA contributor (UM, 268 versus 67 pg/μL; CM, 2824 versus 463 pg/μL). Host and parasite cfDNA distinguished CM by retinopathy (host, AUC 0.715, P = 0.0001; parasite, AUC 0.745, P = 0.0001), but only host cfDNA distinguished fatal cases (AUC 0.715, P = 0.0001). Total cfDNA correlated with neutrophil markers IL-8 (rs = 0.433, P < 0.0001) and myeloperoxidase (rs = 0.683, P < 0.0001).CONCLUSION Quantifying plasma cfDNA is a simple assay useful in identifying children at risk for fatal outcome and has promise as a point-of-care assay. Elevated cfDNA suggests a link with host inflammatory pathways in fatal CM.FUNDING NIH NCATS (AK), Burroughs-Wellcome (AK), and National Health and Medical Research Council of Australia (SJR).
Authors
Iset Medina Vera, Anne Kessler, Li-Min Ting, Visopo Harawa, Thomas Keller, Dylan Allen, Madi Njie, McKenze Moss, Monica Soko, Ajisa Ahmadu, Innocent Kadwala, Stephen Ray, Tonney S. Nyirenda, Wilson L. Mandala, Terrie E. Taylor, Stephen J. Rogerson, Karl B. Seydel, Kami Kim
Abstract
Mycobacterium tuberculosis (Mtb)-specific T cell responses associated with immune control during asymptomatic latent tuberculosis infection (LTBI) remain poorly understood. Using a non-human primate (NHP) aerosol model, we studied the kinetics, phenotypes and functions of Mtb antigen-specific T cells in peripheral and lung compartments of Mtb-infected asymptomatic rhesus macaques by longitudinally sampling blood and bronchoalveolar lavage (BAL), for up to 24 weeks post-infection. We found significantly higher frequencies of Mtb-specific effector and memory CD4 and CD8 T cells producing IFN-γ in the airways compared to peripheral blood, which were maintained throughout the study period. Moreover, Mtb-specific IL-17+ and IL-17/IFN-γ double-positive T cells were present in the airways but were largely absent in the periphery, suggesting that balanced mucosal Th1/Th17 responses are associated with LTBI. The majority of Mtb-specific CD4 T cells that homed to the airways expressed the chemokine receptor CXCR3 and co-expressed CCR6. Notably, CXCR3+CD4+ cells were found in granulomatous and non-granulomatous regions of the lung and inversely correlated with Mtb burden. Our findings provide novel insights into antigen-specific T cell responses associated with asymptomatic Mtb infection that are relevant for developing better strategies to control TB
Authors
Uma Shanmugasundaram, Allison N. Bucsan, Shashank R. Ganatra, Chris Ibegbu, Melanie Quezada, Robert V. Blair, Xavier Alvarez, Vijayakumar Velu, Deepak Kaushal, Jyothi Rengarajan
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