Infectious disease
Abstract
Inhibition of Bruton's tyrosine kinase (BTK) through covalent modifications of its active site (e.g., ibrutinib [IBT]) is a preferred treatment for multiple B cell malignancies. However, IBT-treated patients are more susceptible to invasive fungal infections, although the mechanism is poorly understood. Neutrophils are the primary line of defense against these infections; therefore, we examined the impact of IBT on primary human neutrophil effector activity against Aspergillus fumigatus. IBT significantly impaired the ability of neutrophils to kill A. fumigatus and potently inhibited reactive oxygen species (ROS) production, chemotaxis, and phagocytosis. Importantly, exogenous TNFα fully compensated for defects imposed by IBT and newer-generation BTK inhibitors and restored the ability of neutrophils to contain A. fumigatus hyphal growth. Blocking TNFα did not impact ROS production in healthy neutrophils but prevented exogenous TNFα from rescuing the phenotype of IBT-treated neutrophils. The restorative capacity of TNFα was independent of transcription. Moreover, the addition of TNFα immediately rescued ROS production in IBT-treated neutrophils indicating that TNFα worked through a BTK-independent signaling pathway. Finally, TNFα restored effector activity of primary neutrophils from patients on IBT therapy. Altogether, our data indicate that TNFα rescues the antifungal immunity block imposed by inhibition of BTK in primary human neutrophils.
Authors
Diego A. Vargas-Blanco, Olivia W. Hepworth, Kyle J. Basham, Patricia Simaku, Arianne J. Crossen, Kyle D. Timmer, Alex Hopke, Hannah Brown Harding, Steven R. Vandal, Kirstine N. Jensen, Daniel J. Floyd, Jennifer L. Reedy, Christopher Reardon, Michael K. Mansour, Rebecca A. Ward, Daniel Irimia, Jeremy S. Abramson, Jatin M. Vyas
Abstract
A systems analysis was conducted to determine the potential molecular mechanisms underlying differential immunogenicity and protective efficacy results of a clinical trial of the radiation-attenuated whole sporozoite PfSPZ Vaccine in African infants. Innate immune activation and myeloid signatures at pre-vaccination baseline correlated with protection from Pf parasitemia in placebo controls. These same signatures were associated with susceptibility to parasitemia among infants who received the highest and most protective PfSPZ Vaccine dose. Machine learning identified spliceosome, proteosome, and resting dendritic cell signatures as pre-vaccination features predictive of protection after highest-dose PfSPZ vaccination, whereas baseline CSP-specific IgG predicted non-protection. Pre-vaccination innate inflammatory and myeloid signatures were associated with higher sporozoite-specific IgG Ab response but undetectable PfSPZ-specific CD8+ T-cell responses post-vaccination. Consistent with these human data, innate stimulation in vivo conferred protection against infection by sporozoite injection in malaria-naïve mice while diminishing the CD8+ T-cell response to radiation-attenuated sporozoites. These data suggest a dichotomous role of innate stimulation for malaria protection and induction of protective immunity of whole-sporozoite malaria vaccines. The uncoupling of vaccine-induced protective immunity achieved by Abs from more protective CD8+ T cell responses suggest that PfSPZ Vaccine efficacy in malaria-endemic settings may be constrained by opposing antigen presentation pathways.
Authors
Leetah Senkpeil, Jyoti Bhardwaj, Morgan R. Little, Prasida Holla, Aditi Upadhye, Elizabeth M. Fusco, Phillip A. Swanson II, Ryan E. Wiegand, Michael D. Macklin, Kevin Bi, Barbara J. Flynn, Ayako Yamamoto, Erik L. Gaskin, D. Noah Sather, Adrian L. Oblak, Edward Simpson, Hongyu Gao, W. Nicholas Haining, Kathleen B. Yates, Xiaowen Liu, Tooba Murshedkar, Thomas L. Richie, B. Kim Lee Sim, Kephas Otieno, Simon Kariuki, Xiaoling Xuei, Yunlong Liu, Rafael B. Polidoro, Stephen L. Hoffman, Martina Oneko, Laura C. Steinhardt, Nathan W. Schmidt, Robert A. Seder, Tuan M. Tran
Abstract
BACKGROUND Persistent cough and dyspnea are prominent features of post-acute sequelae of SARS-CoV-2 (also termed ’Long COVID’); however, physiologic measures and clinical features associated with these pulmonary symptoms remain poorly defined. Using longitudinal pulmonary function testing (PFTs) and CT imaging, this study aimed to identify the characteristics and determinants of pulmonary Long COVID. METHODS This single-center retrospective study included 1,097 patients with clinically defined Long COVID characterized by persistent pulmonary symptoms (dyspnea, cough, and chest discomfort) lasting for ≥1 month after resolution of primary COVID infection. RESULTS After exclusion, a total of 929 patients with post-COVID pulmonary symptoms and PFTs were stratified diffusion impairment and restriction as measured by percent predicted diffusion capacity for carbon monoxide (DLCO) and total lung capacity (TLC). Dyspnea was the predominant symptom in the cohort (78%) and had similar prevalence regardless of degree of diffusion impairment or restriction. Longitudinal evaluation revealed diffusion impairment (DLCO ≤80%) and pulmonary restriction (TLC ≤80%) in 51% of the cohort overall (n=479). In multivariable logistic regression analysis (adjusted odds ratio; aOR, 95% confidence interval [CI]), invasive mechanical ventilation during primary infection conferred the greatest increased odds of developing pulmonary Long COVID with diffusion impairment and restriction (aOR=10.9 [4.09-28.6]). Finally, a sub-analysis of CT imaging identified radiographic evidence of fibrosis in this patient population. CONCLUSIONS Longitudinal PFT measurements in patients with prolonged pulmonary symptoms after SARS-CoV-2 infection revealed persistent diffusion impaired restriction as a key feature of pulmonary Long COVID. These results emphasize the importance of incorporating PFTs into routine clinical practice for evaluation of patients with prolonged pulmonary symptoms after resolution of SARS-CoV-2. Subsequent clinical trials should leverage combined symptomatic and quantitative PFT measurements for more targeted enrollment of pulmonary Long COVID patients. FUNDING This work was supported by the National Institute of Allergy and Infectious Diseases (AI156898, K08AI129705), the National Heart, Lung, and Blood Institute (HL153113, OTA21-015E, HL149944), and the COVID-19 Urgent Research Response Fund established by the Hugh Kaul Precision Medicine Network at the University of Alabama at Birmingham.
Authors
Michael John Patton, Donald Benson, Sarah W. Robison, Dhaval Raval, Morgan L. Locy, Kinner Patel, Scott Grumley, Emily B. Levitan, Peter Morris, Matthew Might, Amit Gaggar, Nathaniel Erdmann
Abstract
Sepsis is a leading cause of mortality worldwide, and pneumonia is the most common cause of sepsis in humans. Low levels of high-density lipoprotein cholesterol (HDL-C) levels are associated with an increased risk of death from sepsis, and increasing levels of HDL-C by inhibition of cholesteryl ester transfer protein (CETP) decreases mortality from intraabdominal polymicrobial sepsis in APOE*3-Leiden.CETP mice. Here, we show that treatment with the CETP inhibitor (CETPi) anacetrapib reduced mortality from Streptococcus pneumoniae–induced sepsis in APOE*3-Leiden.CETP and APOA1.CETP mice. Mechanistically, CETP inhibition reduced the host proinflammatory response via attenuation of proinflammatory cytokine transcription and release. This effect was dependent on the presence of HDL, leading to attenuation of immune-mediated organ damage. In addition, CETP inhibition promoted monocyte activation in the blood prior to the onset of sepsis, resulting in accelerated macrophage recruitment to the lung and liver. In vitro experiments demonstrated that CETP inhibition significantly promoted the activation of proinflammatory signaling in peripheral blood mononuclear cells and THP1 cells in the absence of HDL; this may represent a mechanism responsible for improved bacterial clearance during sepsis. These findings provide evidence that CETP inhibition represents a potential approach to reduce mortality from pneumosepsis.
Authors
Haoyu Deng, Wan Yi Liang, Le Qi Chen, Tin Ho Yuen, Basak Sahin, Dragoș M. Vasilescu, Mark Trinder, Keith Walley, Patrick C.N. Rensen, John H. Boyd, Liam R. Brunham
Abstract
To unravel the heterogeneity and molecular signature of effector memory Th2 cells (Tem2), we analyzed 23 individuals’ PBMCs of filaria-infected (Filaria+) and 24 healthy volunteers (Filaria–), with or without coincident house dust mite (HDM) allergic sensitization. Flow cytometry revealed 3 CD4+ Tem subsets — CCR4+CCR6+CRTH2– Tem17, CCR4+CCR6-CRTH2+ Tem2, and CCR6+CCR4+CRTH2+ Tem17.2 — markedly enriched in Filaria+ individuals. These subsets were sorted and analyzed by multiomic single-cell RNA immunoprofiling. SingleR-annotated Th2 cells from Tem2 and Tem17.2 cell subsets had features of pathogenic Th2 effector cells based on their transcriptional signatures, with downregulated CD27 and elevated expression levels of ITGA4, IL17RB, HPGDS, KLRB1, PTGDR2, IL9R, IL4, IL5, and IL13 genes. When the Filaria+ individuals were subdivided based on their allergic status, Tem2 cells in HDM+Filaria+ individuals showed an overall reduction in TCR diversity, suggesting the occurrence of antigen-driven clonal expansion. Moreover, HDM+Filaria+ individuals showed not only an expansion in the frequency of both Tem2 and Tem17.2 cell subsets, but also a change in their molecular program by overexpressing GATA3, IL17RB, CLRF2, and KLRB1, as well as increased antigen-induced IL-4, IL-5, and IL-13 production, suggesting that aeroallergens reshape the transcriptional and functional programming of Th2 cell subsets in human filarial infection toward a pathogenic immunophenotype.
Authors
Pedro H. Gazzinelli-Guimaraes, Brittany Dulek, Phillip Swanson, Justin Lack, Mario Roederer, Thomas B. Nutman
Abstract
The viral kinetics of documented SARS-CoV-2 infections exhibit a high degree of inter-individual variability. We identified six distinct viral shedding patterns, which differed according to peak viral load, duration, expansion rate and clearance rate, by clustering data from 768 infections in the National Basketball Association cohort. Omicron variant infections in previously vaccinated individuals generally led to lower cumulative shedding levels of SARS-CoV-2 than other scenarios. We then developed a mechanistic mathematical model that recapitulated 1510 observed viral trajectories, including viral rebound and cases of reinfection. Lower peak viral loads were explained by a more rapid and sustained transition of susceptible cells to a refractory state during infection, as well as an earlier and more potent late, cytolytic immune response. Our results suggest that viral elimination occurs more rapidly during omicron infection, following vaccination, and following re-infection due to enhanced innate and acquired immune responses. Because viral load has been linked with COVID-19 severity and transmission risk, our model provides a framework for understanding the wide range of observed SARS-CoV-2 infection outcomes.
Authors
Katherine Owens, Shadisadat Esmaeili, Joshua Schiffer
Abstract
Novel biomarkers to identify infectious patients transmitting Mycobacterium tuberculosis are urgently needed to control the global tuberculosis (TB) pandemic. We hypothesized that proteins released into the plasma in active pulmonary TB are clinically useful biomarkers to distinguish TB cases from healthy individuals and patients with other respiratory infections. We applied a highly sensitive non-depletion tandem mass spectrometry discovery approach to investigate plasma protein expression in pulmonary TB cases compared to healthy controls in South African and Peruvian cohorts. Bioinformatic analysis using linear modelling and network correlation analyses identified 118 differentially expressed proteins, significant through three complementary analytical pipelines. Candidate biomarkers were subsequently analysed in two validation cohorts of differing ethnicity using antibody-based proximity extension assays. TB-specific host biomarkers were confirmed. A six-protein diagnostic panel, comprising FETUB, FCGR3B, LRG1, SELL, CD14 and ADA2, differentiated patients with pulmonary TB from healthy controls and patients with other respiratory infections with high sensitivity and specificity in both cohorts. This biomarker panel exceeds the World Health Organisation Target Product Profile specificity criteria for a triage test for TB. The new biomarkers have potential for further development as near-patient TB screening assays, thereby helping to close the case-detection gap that fuels the global pandemic.
Authors
Hannah F. Schiff, Naomi F. Walker, Cesar Ugarte-Gil, Marc Tebruegge, Antigoni Manousopoulou, Spiros D. Garbis, Salah Mansour, Pak Ho Wong, Gabrielle Rockett, Paolo Piazza, Mahesan Niranjan, Andres F. Vallejo, Christopher H. Woelk, Robert J. Wilkinson, Liku B. Tezera, Diana Garay-Baquero, Paul Elkington
Abstract
The lipidome of immune cells during infection has remained unexplored, although evidence of the importance of lipids in the context of immunity is mounting. In this study, we performed untargeted lipidomic analysis of blood monocytes and neutrophils from patients hospitalized for pneumonia and age- and sex-matched noninfectious control volunteers. We annotated 521 and 706 lipids in monocytes and neutrophils, respectively, which were normalized to an extensive set of internal standards per lipid class. The cellular lipidomes were profoundly altered in patients, with both common and distinct changes between the cell types. Changes involved every level of the cellular lipidome: differential lipid species, class-wide shifts, and altered saturation patterns. Overall, differential lipids were mainly less abundant in monocytes and more abundant in neutrophils from patients. One month after hospital admission, lipidomic changes were fully resolved in monocytes and partially in neutrophils. Integration of lipidomic and concurrently collected transcriptomic data highlighted altered sphingolipid metabolism in both cell types. Inhibition of ceramide and sphingosine-1-phosphate synthesis in healthy monocytes and neutrophils resulted in blunted cytokine responses upon stimulation with lipopolysaccharide. These data reveal major lipidomic remodeling in immune cells during infection, and link the cellular lipidome to immune functionality.
Authors
Alex R. Schuurman, Osoul Chouchane, Joe M. Butler, Hessel Peters-Sengers, Sebastiaan Joosten, Xanthe Brands, Bastiaan W. Haak, Natasja A. Otto, Fabrice Uhel, Augustijn Klarenbeek, Christine C.A. van Linge, Antoine van Kampen, Mia Pras-Raves, Michel van Weeghel, Marco van Eijk, Maria J. Ferraz, Daniël R. Faber, Alex de Vos, Brendon P. Scicluna, Frédéric M. Vaz, W. Joost Wiersinga, Tom van der Poll
Abstract
Despite effective antibiotic therapy, brain destructive inflammation often cannot be avoided in pneumococcal meningitis. The causative signals are mediated predominantly through TLR recruited myeloid differentiation primary response adaptor (MyD) 88 as indicated by a dramatic pneumococcal meningitis phenotype of Myd88-/- mice. Because lipoproteins and ssRNA are crucial for recognition of Gram-positive bacteria such as Streptococcus pneumoniae by the host immune system, we comparatively analyzed the disease courses of Myd88-/- and Tlr2/13-/- mice. Their phenotype resemblance indicated TLR2 and -13 as master sensors of Streptococcus pneumoniae in the cerebrospinal fluid. The neutralizing anti-TLR2 antibody (T2.5) and chloroquine (CQ) – the latter applied here as an inhibitor for murine TLR13 and its human orthologue TLR8 – abrogated activation of murine and human primary immune cells exposed to antibiotic-treated Streptococcus pneumoniae. The inhibitory effect of the T2.5/CQ cocktail was stronger than that of dexamethasone, the current standard adjunctive drug for pneumococcal meningitis. Accordingly, TLR2/13 blockade concomitant with ceftriaxone application significantly improved the clinical course of pneumococcal meningitis compared to treatment with ceftriaxone alone or in combination with dexamethasone. Our study implicates the importance of murine TLR13 and human TLR8, besides TLR2, in pneumococcal meningitis pathology, and suggests their blockade as a promising antibiotic therapy adjunct.
Authors
Susanne Dyckhoff-Shen, Ilias Masouris, Heba Islam, Sven Hammerschmidt, Barbara Angele, Veena Marathe, Jan Buer, Stefanie Völk, Hans-Walter Pfister, Matthias Klein, Uwe Koedel, Carsten J. Kirschning
Abstract
With antimicrobial resistance (AMR) emerging as a major threat to global health, monoclonal antibodies (MAbs) have become a promising means to combat difficult-to-treat AMR infections. Unfortunately, in contrast with standard antimicrobials, for which there are well-validated clinical laboratory methodologies to determine whether an infecting pathogen is susceptible or resistant to a specific antimicrobial drug, no assays have been described that can inform clinical investigators or clinicians regarding the clinical efficacy of a MAb against a specific pathogenic strain. Using Acinetobacter baumannii as a model organism, we established and validated 2 facile clinical susceptibility assays, which used flow cytometry and latex bead agglutination, to determine susceptibility (predicting in vivo efficacy) or resistance (predicting in vivo failure) of 1 newly established and 3 previously described anti–A. baumannii MAbs. These simple assays exhibited impressive sensitivity, specificity, and reproducibility, with clear susceptibility breakpoints that predicted the in vivo outcomes in our preclinical model with excellent fidelity. These MAb susceptibility assays have the potential to enable and facilitate clinical development and deployment of MAbs that generally target the surface of microbes.
Authors
Matthew J. Slarve, Neven Bowler, Elizabeth Burk, Jun Yan, Ulrike Carlino-MacDonald, Thomas A. Russo, Brian M. Luna, Brad Spellberg
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