Hypoxia occurs in many pathological conditions, including chronic inflammation and tumors, and is considered to be an inhibitor of T cell function. However, robust T cell responses occur at many hypoxic inflammatory sites, suggesting that functions of some subsets are stimulated under low oxygen conditions. Here, we investigated how hypoxic conditions influence human T cell functions and found that, in contrast to naive and central memory T cells (TN and TCM), hypoxia enhances the proliferation, viability, and cytotoxic action of effector memory T cells (TEM). Enhanced TEM expansion in hypoxia corresponded to high hypoxia-inducible factor 1α (HIF1α) expression and glycolytic activity compared with that observed in TN and TCM. We determined that the glycolytic enzyme GAPDH negatively regulates
Yang Xu, Arindam Chaudhury, Ming Zhang, Barbara Savoldo, Leonid S. Metelitsa, John Rodgers, Jason T. Yustein, Joel R. Neilson, Gianpietro Dotti
Successful bacterial pathogens produce an array of virulence factors that allow subversion of the immune system and persistence within the host. For example, uropathogenic
Anna Waldhuber, Manoj Puthia, Andreas Wieser, Christine Cirl, Susanne Dürr, Silke Neumann-Pfeifer, Simone Albrecht, Franziska Römmler, Tina Müller, Yunji Zheng, Sören Schubert, Olaf Groß, Catharina Svanborg, Thomas Miethke
The cross-reactivity of T cells with pathogen- and self-derived peptides has been implicated as a pathway involved in the development of autoimmunity. However, the mechanisms that allow the clonal T cell antigen receptor (TCR) to functionally engage multiple peptide–major histocompatibility complexes (pMHC) are unclear. Here, we studied multiligand discrimination by a human, preproinsulin reactive, MHC class-I–restricted CD8+ T cell clone (1E6) that can recognize over 1 million different peptides. We generated high-resolution structures of the 1E6 TCR bound to 7 altered peptide ligands, including a pathogen-derived peptide that was an order of magnitude more potent than the natural self-peptide. Evaluation of these structures demonstrated that binding was stabilized through a conserved lock-and-key–like minimal binding footprint that enables 1E6 TCR to tolerate vast numbers of substitutions outside of this so-called hotspot. Highly potent antigens of the 1E6 TCR engaged with a strong antipathogen-like binding affinity; this engagement was governed though an energetic switch from an enthalpically to entropically driven interaction compared with the natural autoimmune ligand. Together, these data highlight how T cell cross-reactivity with pathogen-derived antigens might break self-tolerance to induce autoimmune disease.
David K. Cole, Anna M. Bulek, Garry Dolton, Andrea J. Schauenberg, Barbara Szomolay, William Rittase, Andrew Trimby, Prithiviraj Jothikumar, Anna Fuller, Ania Skowera, Jamie Rossjohn, Cheng Zhu, John J. Miles, Mark Peakman, Linda Wooldridge, Pierre J. Rizkallah, Andrew K. Sewell
Cell ablation is a powerful tool for studying cell lineage and/or function; however, current cell-ablation models have limitations. Intermedilysin (ILY), a cytolytic pore-forming toxin that is secreted by
Dechun Feng, Shen Dai, Fengming Liu, Yosuke Ohtake, Zhou Zhou, Hua Wang, Yonggang Zhang, Alison Kearns, Xiao Peng, Faliang Zhu, Umar Hayat, Man Li, Yong He, Mingjiang Xu, Chunling Zhao, Min Cheng, Lining Zhang, Hong Wang, Xiaofeng Yang, Cynthia Ju, Elizabeth C. Bryda, Jennifer Gordon, Kamel Khalili, Wenhui Hu, Shuxin Li, Xuebin Qin, Bin Gao
A eubiotic microbiota influences many physiological processes in the metazoan host, including development and intestinal homeostasis. Here, we have shown that the intestinal microbiota modulates inflammatory responses caused by sex steroid deficiency, leading to trabecular bone loss. In murine models, sex steroid deficiency increased gut permeability, expanded Th17 cells, and upregulated the osteoclastogenic cytokines TNFα (TNF), RANKL, and IL-17 in the small intestine and the BM. In germ-free (GF) mice, sex steroid deficiency failed to increase osteoclastogenic cytokine production, stimulate bone resorption, and cause trabecular bone loss, demonstrating that the gut microbiota is central in sex steroid deficiency–induced trabecular bone loss. Furthermore, we demonstrated that twice-weekly treatment of sex steroid–deficient mice with the probiotics
Jau-Yi Li, Benoit Chassaing, Abdul Malik Tyagi, Chiara Vaccaro, Tao Luo, Jonathan Adams, Trevor M. Darby, M. Neale Weitzmann, Jennifer G. Mulle, Andrew T. Gewirtz, Rheinallt M. Jones, Roberto Pacifici
Immune aging results in progressive loss of both protective immunity and T cell–mediated suppression, thereby conferring susceptibility to a combination of immunodeficiency and chronic inflammatory disease. Here, we determined that older individuals fail to generate immunosuppressive CD8+CCR7+ Tregs, a defect that is even more pronounced in the age-related vasculitic syndrome giant cell arteritis. In young, healthy individuals, CD8+CCR7+ Tregs are localized in T cell zones of secondary lymphoid organs, suppress activation and expansion of CD4 T cells by inhibiting the phosphorylation of membrane-proximal signaling molecules, and effectively inhibit proliferative expansion of CD4 T cells in vitro and in vivo. We identified deficiency of NADPH oxidase 2 (NOX2) as the molecular underpinning of CD8 Treg failure in the older individuals and in patients with giant cell arteritis. CD8 Tregs suppress by releasing exosomes that carry preassembled NOX2 membrane clusters and are taken up by CD4 T cells. Overexpression of NOX2 in aged CD8 Tregs promptly restored suppressive function. Together, our data support NOX2 as a critical component of the suppressive machinery of CD8 Tregs and suggest that repairing NOX2 deficiency in these cells may protect older individuals from tissue-destructive inflammatory disease, such as large-vessel vasculitis.
Zhenke Wen, Yasuhiro Shimojima, Tsuyoshi Shirai, Yinyin Li, Jihang Ju, Zhen Yang, Lu Tian, Jörg J. Goronzy, Cornelia M. Weyand
Inflammasomes form as the result of the intracellular presence of danger-associated molecular patterns and mediate the release of active IL-1β, which influences a variety of inflammatory responses. Excessive inflammasome activation results in severe inflammatory conditions, but physiological IL-1β secretion is necessary for intestinal homeostasis. Here, we have described a mechanism of NLRP3 inflammasome regulation by tyrosine phosphorylation of NLRP3 at Tyr861. We demonstrated that protein tyrosine phosphatase non-receptor 22 (PTPN22), variants in which are associated with chronic inflammatory disorders, dephosphorylates NLRP3 upon inflammasome induction, allowing efficient NLRP3 activation and subsequent IL-1β release. In murine models, PTPN22 deficiency resulted in pronounced colitis, increased NLRP3 phosphorylation, but reduced levels of mature IL-1β. Conversely, patients with inflammatory bowel disease (IBD) that carried an autoimmunity-associated PTPN22 variant had increased IL-1β levels. Together, our results identify tyrosine phosphorylation as an important regulatory mechanism for NLRP3 that prevents aberrant inflammasome activation.
Marianne R. Spalinger, Stephanie Kasper, Claudia Gottier, Silvia Lang, Kirstin Atrott, Stephan R. Vavricka, Sylvie Scharl, Petrus M. Gutte, Markus G. Grütter, Hans-Dietmar Beer, Emmanuel Contassot, Andrew C. Chan, Xuezhi Dai, David J. Rawlings, Florian Mair, Burkhard Becher, Werner Falk, Michael Fried, Gerhard Rogler, Michael Scharl
Adoptive immunotherapy with regulatory T cells (Tregs) is a promising treatment for allograft rejection and graft-versus-host disease (GVHD). Emerging data indicate that, compared with polyclonal Tregs, disease-relevant antigen-specific Tregs may have numerous advantages, such as a need for fewer cells and reduced risk of nonspecific immune suppression. Current methods to generate alloantigen-specific Tregs rely on expansion with allogeneic antigen-presenting cells, which requires access to donor and recipient cells and multiple MHC mismatches. The successful use of chimeric antigen receptors (CARs) for the generation of antigen-specific effector T cells suggests that a similar approach could be used to generate alloantigen-specific Tregs. Here, we have described the creation of an HLA-A2–specific CAR (A2-CAR) and its application in the generation of alloantigen-specific human Tregs. In vitro, A2-CAR–expressing Tregs maintained their expected phenotype and suppressive function before, during, and after A2-CAR–mediated stimulation. In mouse models, human A2-CAR–expressing Tregs were superior to Tregs expressing an irrelevant CAR at preventing xenogeneic GVHD caused by HLA-A2+ T cells. Together, our results demonstrate that use of CAR technology to generate potent, functional, and stable alloantigen-specific human Tregs markedly enhances their therapeutic potential in transplantation and sets the stage for using this approach for making antigen-specific Tregs for therapy of multiple diseases.
Katherine G. MacDonald, Romy E. Hoeppli, Qing Huang, Jana Gillies, Dan S. Luciani, Paul C. Orban, Raewyn Broady, Megan K. Levings
Alloreactive donor T cells are the driving force in the induction of graft-versus-host disease (GVHD), yet little is known about T cell metabolism in response to alloantigens after hematopoietic cell transplantation (HCT). Here, we have demonstrated that donor T cells undergo metabolic reprograming after allogeneic HCT. Specifically, we employed a murine allogeneic BM transplant model and determined that T cells switch from fatty acid β-oxidation (FAO) and pyruvate oxidation via the tricarboxylic (TCA) cycle to aerobic glycolysis, thereby increasing dependence upon glutaminolysis and the pentose phosphate pathway. Glycolysis was required for optimal function of alloantigen-activated T cells and induction of GVHD, as inhibition of glycolysis by targeting mTORC1 or 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) ameliorated GVHD mortality and morbidity. Together, our results indicate that donor T cells use glycolysis as the predominant metabolic process after allogeneic HCT and suggest that glycolysis has potential as a therapeutic target for the control of GVHD.
Hung D. Nguyen, Shilpak Chatterjee, Kelley M.K. Haarberg, Yongxia Wu, David Bastian, Jessica Heinrichs, Jianing Fu, Anusara Daenthanasanmak, Steven Schutt, Sharad Shrestha, Chen Liu, Honglin Wang, Hongbo Chi, Shikhar Mehrotra, Xue-Zhong Yu
Avian H7N9 influenza viruses are group 2 influenza A viruses that have been identified as the etiologic agent for a current major outbreak that began in China in 2013 and may pose a pandemic threat. Here, we examined the human H7-reactive antibody response in 75 recipients of a monovalent inactivated A/Shanghai/02/2013 H7N9 vaccine. After 2 doses of vaccine, the majority of donors had memory B cells that secreted IgGs specific for H7 HA, with dominant responses against single HA subtypes, although frequencies of H7-reactive B cells ranged widely between donors. We isolated 12 naturally occurring mAbs with low half-maximal effective concentrations for binding, 5 of which possessed neutralizing and HA-inhibiting activities. The 5 neutralizing mAbs exhibited narrow breadth of reactivity with influenza H7 strains. Epitope-mapping studies using neutralization escape mutant analysis, deuterium exchange mass spectrometry, and x-ray crystallography revealed that these neutralizing mAbs bind near the receptor-binding pocket on HA. All 5 neutralizing mAbs possessed low numbers of somatic mutations, suggesting the clones arose from naive B cells. The most potent mAb, H7.167, was tested as a prophylactic treatment in a mouse intranasal virus challenge study, and systemic administration of the mAb markedly reduced viral lung titers.
Natalie J. Thornburg, Heng Zhang, Sandhya Bangaru, Gopal Sapparapu, Nurgun Kose, Rebecca M. Lampley, Robin G. Bombardi, Yingchun Yu, Stephen Graham, Andre Branchizio, Sandra M. Yoder, Michael T. Rock, C. Buddy Creech, Kathryn M. Edwards, David Lee, Sheng Li, Ian A. Wilson, Adolfo García-Sastre, Randy A. Albrecht, James E. Crowe Jr.