Biology subjects

Teijaro, J. R.

Publications and source records attributed to Teijaro, J. R..

15 recordsLinked to original sources

bioRxiv2026

Pan-Coronavirus Protease Engagement and Differentiated Pharmacology of Antiviral Candidate CMX990

COVID-19 highlighted the need for antivirals that can be rapidly deployed against both current and future coronavirus threats. CMX990 is a clinical stage coronavirus main protease (Mpro) inhibitor bearing a unique trifluoromethoxymethyl ketone warhead. Here, we broadly evaluate its pan-coronavirus target engagement, antiviral breadth, and pharmacologic differentiation. Across a reporter panel of 24 Mpro enzymes spanning alpha-, beta-, delta-, and gamma-coronaviruses, CMX990 retained robust potent activity, including against nirmatrelvir-resistant SARS-CoV-2 variants. In direct comparison, nirmatrelvir and ensitrelvir showed diminished potency against non-SARS-CoV-2 coronaviruses. Live-virus assays corroborated this breadth, with potent, selective activity against SARS-CoV-2, SARS-CoV-1, MERS-CoV, and additional human coronaviruses. Structural studies revealed a conserved covalent binding mode centered on the catalytic Cys of coronavirus Mpro. In serial-passage studies, resistance emerged only after approximately twice as many serial passages under CMX990 selection as under nirmatrelvir selection, without selecting for the canonical nirmatrelvir-resistance substitution E166V. Extracellular washout experiments revealed superior persistence of antiviral activity relative to nirmatrelvir, consistent with durable target engagement. In a murine SARS-CoV-2 infection model, once-daily CMX990 protected against weight loss and reduced lung viral titers to near baseline levels. Collectively, these findings identify CMX990 as a structurally and functionally validated pan-coronavirus protease inhibitor supporting its potential as a pandemic-ready antiviral candidate.

pharmacology and toxicology↗

bioRxiv2026

Beyond the blood: Tissue-resident immunity shapes SARS-CoV-2 vaccine antibody responses

Infections and vaccinations elicit coordinated humoral and cellular adaptive immune responses that together provide protection. In addition to antibodies, pathogen-specific memory T and Bcells persist in blood and tissues, but it remains unclear how their composition and spatial distribution relate to serum antibody titers, the most common correlate of vaccine-induced protection. Understanding these relationships is essential for predicting vaccine efficacy and optimizing immunization strategies. We analyzed tissues from 58 adult human organ donors vaccinated against SARS-CoV-2, including individuals with and without prior infection. Using multivariate imputation, dimensionality reduction, and correlation, regression, and causal analyses, we identified immune signatures linking memory B cell, CD4 T cell, and CD8 T cell subsets in spleen, lung, and lung-draining lymph nodes with antibody titers and neutralizing activity. Our analyses indicate that humoral immunity is driven primarily by virus-specific B cellsand CD4 T cells in lymphoid tissues rather than blood, whereas tissue-localized CD8 T cell responses, although correlated with antibody levels, develop independently. These findings demonstrate that cross-sectional immune profiling across multiple tissues recapitulates established immunological principles and reveal that serum antibody responses emerge from coordinated cellular immune responses distributed throughout the body.

immunology↗

bioRxiv2025

Integrated phenotypic screening and chemical proteomics identifies ETF1 ligands that modulate viral translation and replication

Emerging and re-emerging viruses pose a significant threat to global health. Although direct-acting antivirals have shown success, their efficacy is limited by the rapid emergence of drug-resistant viral variants. Hence, there is an urgent need for additional broad spectrum antiviral therapeutic strategies. Here, we identify by phenotypic screening a set of stereochemically defined photoreactive small molecules (photo-stereoprobes) that stereoselectively suppress SARS-CoV-2 replication in human lung epithelial cells. Structure-activity relationship-guided chemical proteomics identified the eukaryotic translation termination factor 1 (ETF1) as a target of the photo-stereoprobes, and this interaction was recapitulated with recombinant purified ETF1. We found that the photo-stereoprobes modulate programmed ribosomal frameshifting mechanisms essential for SARS-CoV-2 infection without causing ETF1 degradation, thus distinguishing the photo-stereoprobes from other known ETF1-directed small molecules. We finally show that the photo-stereoprobes also inhibit the replication of additional viruses with non-canonical ribosomal frameshifting mechanisms. Our findings thus identify a mechanistically distinct class of ETF1 ligands that implicate host translation termination processes as a potential target for antiviral development. SIGNIFICANCE STATEMENTThe identification of broad-spectrum antivirals that target host proteins is a desirable strategy to combat emerging viral infections given the rapid escape potential of viruses and the need to develop new countermeasures for clinically significant pathogens. Here, we integrate phenotypic screening and chemical proteomics to identify photo-stereoprobe small molecules that inhibit the replication of multiple viruses. We show that these compounds bind the protein eukaryotic peptide chain release factor subunit 1 (ETF1) and modulate programmed ribosomal frameshifting. Unlike previously described ligands for ETF1, which lead to proteasomal destruction of the protein, we did not find that the photo-stereoprobes altered ETF1 content in cells. Our findings thus point to an opportunity to pharmacologically modulate a host protein implicated in programmed ribosomal frameshifting as a strategy to combat infection of viruses from different families.

microbiology↗

bioRxiv2024

Reshaping the tumor microenvironment by degrading glycoimmune checkpoints Siglec-7 and -9

Cancer treatment has been rapidly transformed by the development of immune checkpoint inhibitors targeting CTLA-4 and PD-1/PD-L1. However, many patients fail to respond, especially those with an immunosuppressive tumor microenvironment (TME), suggesting the existence of additional immune checkpoints that act through orthogonal mechanisms. Sialic acid-binding immunoglobulin-like lectin (Siglec)-7 and -9 are newly designated glycoimmune checkpoints that are abundantly expressed by tumor-infiltrating myeloid cells. We discovered that T cells express only basal levels of Siglec transcripts; instead, they acquire Siglec-7 and -9 from interacting myeloid cells in the TME via trogocytosis, which impairs their activation and effector function. Mechanistically, Siglec-7 and -9 suppress T cell activity by dephosphorylating T cell receptor (TCR)-related signaling cascades. Using sulfur fluoride exchange (SuFEx) click chemistry, we developed a ligand that binds to Siglec-7 and -9 with high-affinity and exclusive specificity. Using this ligand, we constructed a Siglec-7/9 degrader that targets membrane Siglec-7 and -9 to the lysosome for degradation. Administration of this degrader induced efficient Siglec degradation in both T cells and myeloid cells in the TME. We found that Siglec-7/9 degradation has a negligible effect on macrophage phagocytosis, but significantly enhances T cell anti-tumor immunity. The degrader, particularly when combined with anti-CTLA-4, enhanced macrophage antigen presentation, reshaped the TME, and resulted in long-lasting T cell memory and excellent tumor control in multiple murine tumor models. These findings underscore the need to consider exogenous checkpoints acquired by T cells in the TME when selecting specific checkpoint blockade therapy to enhance T cell immunity.

immunology↗

bioRxiv2023

Autoimmunity associated allele of tyrosine phosphatase gene PTPN22 enhances anti-viral immunity

AbstractThe 1858C>T allele of the tyrosine phosphatase PTPN22 is present in 5-10% of the North American population and is strongly associated with numerous autoimmune diseases. Although research has been done to define how this allele potentiates autoimmunity, the influence PTPN22 and its pro-autoimmune allele has in anti-viral immunity remains poorly defined. Here, we use single cell RNA- sequencing and functional studies to interrogate the impact of this pro- autoimmune allele on anti-viral immunity during Lymphocytic Choriomeningitis Virus clone 13 (LCMV-cl13) infection. Mice homozygous for this allele (PEP- 619WW) clear the LCMV-cl13 virus whereas wildtype (PEP-WT) mice cannot. This is associated with enhanced anti-viral CD4 T cell responses and a more immunostimulatory CD8- cDC phenotype. Adoptive transfer studies demonstrated that PEP-619WW enhanced anti-viral CD4 T cell function through virus-specific CD4 T cell intrinsic and extrinsic mechanisms. Taken together, our data show that the pro-autoimmune allele of Ptpn22 drives a beneficial anti-viral immune response thereby preventing what is normally a chronic virus infection. Author SummaryPTPN22 and its alternative allele, 1858C>T, has largely been studied in the context of autoimmunity. Through these studies, researchers defined roles for PTPN22 in regulating T lymphocyte activation, myeloid cell cytokine production, and macrophage polarization. Despite these immune pathways being critical for anti-viral immunity, little work has studied how this allele impacts virus infection. In this study, we examine gene expression and function of immune cell subsets to demonstrate how a common allelic variant of PTPN22, which strongly increases the risk of autoimmune disease, promotes successful clearance of an otherwise chronic viral infection.

immunology↗

bioRxiv2023

Covalent targeting as a common mechanism for inhibiting NLRP3 inflammasome assembly.

The NLRP3 inflammasome is a cytosolic protein complex important for the regulation and secretion of inflammatory cytokines including IL-1{beta} and IL-18. Aberrant overactivation of NLRP3 is implicated in numerous inflammatory disorders. However, the activation and regulation of NLRP3 inflammasome signaling remains poorly understood, limiting our ability to develop pharmacologic approaches to target this important inflammatory complex. Here, we developed and implemented a high-throughput screen to identify compounds that inhibit inflammasome assembly and activity. From this screen we identify and profile inflammasome inhibition of 20 new covalent compounds across 9 different chemical scaffolds, as well as many known inflammasome covalent inhibitors. Intriguingly, our results indicate that NLRP3 possesses numerous reactive cysteines on multiple domains whose covalent targeting blocks activation of this inflammatory complex. Specifically, focusing on compound VLX1570, which possesses multiple electrophilic moieties, we demonstrate that this compound allows covalent, intermolecular crosslinking of NLRP3 cysteines to inhibit inflammasome assembly. Our results, along with the recent identification of numerous covalent molecules that inhibit NLRP3 inflammasome activation, suggests that NLRP3 serves as a cellular electrophile sensor important for coordinating inflammatory signaling in response to redox stress. Further, our results support the potential for covalent cysteine modification of NLRP3 for regulating inflammasome activation and activity.

biochemistry↗

bioRxiv2022

Selective inhibitors of JAK1 targeting a subtype-restricted allosteric cysteine

The JAK family of non-receptor tyrosine kinases includes four subtypes (JAK1, JAK2, JAK3, and TYK2) and is responsible for signal transduction downstream of diverse cytokine receptors. JAK inhibitors have emerged as important therapies for immuno(onc)ological disorders, but their use is limited by undesirable side effects presumed to arise from poor subtype selectivity, a common challenge for inhibitors targeting the ATP-binding pocket of kinases. Here, we describe the chemical proteomic discovery of a druggable allosteric cysteine present in the non-catalytic pseudokinase domain of JAK1 (C817) and TYK2 (C838), but absent from JAK2 or JAK3. Electrophilic compounds selectively engaging this site block JAK1-dependent transphosphorylation and cytokine signaling, while appearing to act largely as "silent" ligands for TYK2. Importantly, the allosteric JAK1 inhibitors do not impair JAK2-dependent cytokine signaling and are inactive in cells expressing a C817A JAK1 mutant. Our findings thus reveal an allosteric approach for inhibiting JAK1 with unprecedented subtype selectivity.

pharmacology and toxicology↗

bioRxiv2022

Engineering SARS-CoV-2 neutralizing antibodies for increased potency and reduced viral escape

The rapid spread of SARS-CoV-2 variants poses a constant threat of escape from monoclonal antibody and vaccine countermeasures. Mutations in the ACE2 receptor binding site on the surface S protein have been shown to disrupt antibody binding and prevent viral neutralization. Here, we use a directed evolution-based approach to engineer three neutralizing antibodies for enhanced binding to S protein. The engineered antibodies showed increased in vitro functional activity in terms of neutralization potency and/or breadth of neutralization against viral variants. Deep mutational scanning revealed that higher binding affinity reduced the total number of viral escape mutations. Studies in the Syrian hamster model showed two examples where the affinity matured antibody provided superior protection compared to the parental antibody. These data suggest that monoclonal antibodies for anti-viral indications could benefit from in vitro affinity maturation to reduce viral escape pathways and appropriate affinity maturation in vaccine immunization could help resist viral variation.

bioengineering↗

bioRxiv2021

A protective broadly cross-reactive human antibody defines a conserved site of vulnerability on beta-coronavirus spikes

Broadly neutralizing antibodies (bnAbs) to coronaviruses (CoVs) are valuable in their own right as prophylactic and therapeutic reagents to treat diverse CoVs and, importantly, as templates for rational pan-CoV vaccine design. We recently described a bnAb, CC40.8, from a coronavirus disease 2019 (COVID-19)-convalescent donor that exhibits broad reactivity with human beta-coronaviruses ({beta}-CoVs). Here, we showed that CC40.8 targets the conserved S2 stem-helix region of the coronavirus spike fusion machinery. We determined a crystal structure of CC40.8 Fab with a SARS-CoV-2 S2 stem-peptide at 1.6 [A] resolution and found that the peptide adopted a mainly helical structure. Conserved residues in {beta}-CoVs interacted with CC40.8 antibody, thereby providing a molecular basis for its broad reactivity. CC40.8 exhibited in vivo protective efficacy against SARS-CoV-2 challenge in two animal models. In both models, CC40.8-treated animals exhibited less weight loss and reduced lung viral titers compared to controls. Furthermore, we noted CC40.8-like bnAbs are relatively rare in human COVID-19 infection and therefore their elicitation may require rational structure-based vaccine design strategies. Overall, our study describes a target on {beta}-CoV spike proteins for protective antibodies that may facilitate the development of pan-{beta}-CoV vaccines. SUMMARYA human mAb isolated from a COVID-19 donor defines a protective cross-neutralizing epitope for pan-{beta}-CoV vaccine design strategies

immunology↗

bioRxiv2021

Sialic acid ligands of CD28 block co-stimulation of T cells

Effector T cells comprise the cellular arm of the adaptive immune system and are essential for mounting immune responses against pathogens and cancer. To reach effector status, co-stimulation through CD28 is required. Here, we report that sialic acid-containing glycans on the surface of both T cells and APCs are alternative ligands of CD28 that compete with binding to its well-documented activatory ligand CD80 on the APC, resulting in attenuated co-stimulation. Removal of sialic acids enhances T cell activation and enhances the activity of effector T cells made hypofunctional via chronic viral infection through a mechanism that is synergistic with antibody blockade of the inhibitory PD-1 axis. These results reveal a previously unrecognized role for sialic acids in attenuation of CD28 mediated co-stimulation of T cells. One Sentence SummarySialic acids attenuate the second signal required for T cell activation.

immunology↗

bioRxiv2020

Identification of an N-acetylneuraminic acid-presenting bacteria isolated from a healthy human microbiome

N-acetylneuraminic acid is the most abundant sialic acid in humans and is generally expressed as the terminal sugar on intestinal mucus glycans. Several pathogenic bacterial species harvest sialic acid from the mucus, diet, as well as other intestinal sources and display this sugar on their own surface to evade sialic acid-binding immunoglobulin-type lectin (Siglec)-mediated host immune surveillance. While previous studies have identified bacterial enzymes associated with sialic acid catabolism, no reported methods permit the selective labeling, tracking, and quantitation of sialic acid-presenting microbes within complex multi-microbial systems. Here, we apply an interdisciplinary approach combining metabolic labeling, click chemistry, metagenomic, and whole-genome sequencing to selectively track and identify sialic acid-presenting microbes from a cultured healthy human fecal microbiome. We isolated and identified a new strain of Escherichia coli that incorporates sialic acid onto its own surface. Analysis of the sequence data reveals that this E. coli strain encodes for the NanT, NeuA, and NeuS genes necessary for harvesting environmental sialic acid and generating the capsular polysialic acid. We envision that this method is applicable to the detection and quantitation of sialic acid-presenting bacteria from human, animal, and environmental microbiomes, as well as investigating the importance of other carbohydrates to commensal and pathogenic bacteria.

microbiology↗

bioRxiv2020

TLR9-activated B cells improve their regulatory function by endogenously produced catecholamines

The sympathetic nervous system (SNS) contributes to immune balance by promoting anti-inflammatory B cells. However, whether B cells possess a self-regulating mechanism by which they modulate regulatory B cell (Breg) function is not well understood. In this study, we investigated the ability of B cells to synthesize catecholamines upon stimulation with different B cell activators. We found, that expression of the enzymes required to generate catecholamines, is upregulated by TLR9. TLR-9-specific expression of tyrosine hydroxylase (TH) correlated with upregulation of adrenergic receptors, enhanced IL-10 production, and with an overexpression of the co-inhibitory ligands PD-L1 and FasL. Moreover, concomitant stimulation of {beta}1-3-adrenergic receptors together with a BCR/TLR9 stimulus enhances the anti-inflammatory potential of Bregs to suppress CD4 T cells, a crucial population in the pathogenesis of autoimmune diseases, like rheumatoid arthritis. In conclusion, our data show that B cells possess autonomous mechanisms to modulate their regulatory function. These findings help to better understand the function of Bregs in autoimmune diseases and the interplay of sympathetic nervous system and B cell function.

immunology↗

bioRxiv2020

Rapid isolation of potent SARS-CoV-2 neutralizing antibodies and protection in a small animal model

The development of countermeasures to prevent and treat COVID-19 is a global health priority. In under 7 weeks, we enrolled a cohort of SARS-CoV-2-recovered participants, developed neutralization assays to interrogate serum and monoclonal antibody responses, adapted our high throughput antibody isolation, production and characterization pipeline to rapidly screen over 1000 antigen-specific antibodies, and established an animal model to test protection. We report multiple highly potent neutralizing antibodies (nAbs) and show that passive transfer of a nAb provides protection against high-dose SARS-CoV-2 challenge in Syrian hamsters. The study suggests a role for nAbs in prophylaxis, and potentially therapy, of COVID-19. The nAbs define protective epitopes to guide vaccine design.

immunology↗

bioRxiv2020

ISG15 drives immune pathology and respiratory failure during viral infection

Cytokine storm during respiratory viral infection is an indicator of disease severity and poor prognosis. Type 1 interferon (IFN-I) production and signaling has been reported to be causal in cytokine storm-associated pathology in several respiratory viral infections, however, the mechanisms by which IFN-I promotes disease pathogenesis remain poorly understood. Here, using Usp18-deficient, USP18 enzymatic-inactive and Isg15-deficient mouse models, we report that lack of deISGylation during persistent viral infection leads to severe immune pathology characterized by hematological disruptions, cytokine amplification, lung vascular leakage and death. This pathology requires T cells but not T cell-intrinsic deletion of Usp18. However, lack of Usp18 in myeloid cells mimicked the pathological manifestations observed in Usp18-/- or Usp18C61A mice which were dependent on Isg15. We further mechanistically demonstrate that interrupting the ISGylation/deISGylation circuit increases extracellular levels of ISG15 which is accompanied by inflammatory neutrophil accumulation to the lung. Importantly, neutrophil depletion reversed morbidity and mortality in Usp18C61A mice. In summary, we reveal that the enzymatic function of Usp18 is crucial for regulating extracellular release of ISG15. This is accompanied by altered neutrophil differentiation, cytokine amplification and mortality following persistent viral infection. Moreover, our results suggest that extracellular ISG15 may drive the inflammatory pathology observed and could be both a prospective predictor of disease outcome and a therapeutic target during severe respiratory viral infections.

immunology↗

bioRxiv2020

Detecting Tumor Specific Antigen-Reactive T cells from Tumor Infiltrating Lymphocytes via Interaction Dependent Fucosyl-biotinylation

Re-activation and clonal expansion of tumor specific antigen (TSA)-reactive T cells are critical to the success of checkpoint blockade and adoptive transfer of tumor-infiltrating lymphocyte (TIL) based therapies. There are no reliable markers to specifically identify the repertoire of TSA-reactive T cells due to their heterogeneous composition. Here we introduce FucoID as a general platform to detect endogenous antigen-specific T cells and study their biology. Through this interaction dependent labeling approach, TSA-reactive T cells can be detected and separated from bystander T cells in primary tumor digests based on their cell-surface enzymatic fucosyl-biotinylation. Compared to bystander TILs, TSA-reactive TILs possess a distinct TCR repertoire and unique gene features. Though exhibiting a dysfunctional phenotype, this subset of TILs possesses substantial capabilities of proliferation and tumor specific killing. FucoID features genetic manipulation-free procedures and a quick turnover cycle, and therefore should have the potential of accelerating the pace of personalized cancer treatment. HighlightsInteraction dependent fucosylation enables the detection and isolation of bona fide intratumoral tumor specific antigen-reactive T cells Tumor specific antigen-reactive CD8+ T cells possess capabilities to be expanded and adoptively transferred for tumor control Tumor specific antigen-reactive CD8+ T cells feature oligoclonal expansion and upregulate genes for the steroid biosynthesis and metabolic process Intratumoral bystander CD8+ T cells can be separated into two groups based on PD-1 expression that feature distinct gene modules

immunology↗