Immunology
Abstract
Neonatal life is marked by rapid antigen exposure, necessitating establishment of peripheral immune tolerance via conversion of naïve CD4+ T cells into regulatory T cells (Tregs). Here, we demonstrated heightened capacity for FOXP3 expression and tolerogenic function among cord blood versus adult blood naive CD4+ T cells and showed that this is linked to their unique metabolic profile and elevated expression of the NADase, CD38. Early-life naïve CD4+ T cells demonstrated a metabolic preference for glycolysis, which directly facilitated their differentiation trajectory. We revealed an age-dependent gradient in CD38 levels on naïve CD4+ T cells and showed that high CD38 expression contributes to both the glycolytic state and tolerogenic potential of neonatal CD4+ T cells, effects that were mediated at least in part via the NAD-dependent deacetylase SIRT1. Thus, the early-life window for peripheral tolerance in humans is critically enabled by the immunometabolic state of the naïve CD4+ compartment.
Authors
Laura R. Dwyer, Andrea M. DeRogatis, Sean Clancy, Victoire Gouirand, Charles Chien, Elizabeth E. Rogers, Scott P. Oltman, Laura L. Jelliffe-Pawlowski, Theo van den Broek, Femke van Wijk, Susan V. Lynch, Rachel L. Rutishauser, Allon Wagner, Alexis J. Combes, Tiffany C. Scharschmidt
Abstract
Integrin-targeted therapies are under investigation for HIV associated neuroinflammation, yet their impact on CNS anti-viral immunity remains undefined. We examined the role of α4 integrin in T cell mediated neuroimmune surveillance using SIV-infected macaques with α4 blockade and T cell-specific α4-deficient mice. In macaques, α4 blockade preserved CD4 Th1 cell access to the brain parenchyma but impaired CD8 effector recruitment, disrupting antiviral control. Despite stable cerebrospinal fluid viral loads, hippocampal SIV RNA increased under blockade. Single-cell analyses revealed α4 enrichment in CD8 effector memory (TEM) cells; blockade reduced inferred CD8 TEM-monocyte interactions and heightened innate immune activation in the hippocampus. Microscopy demonstrated persistent SIV-induced microglial simplification despite treatment. Th1 CD4 effectors correlated positively with gray matter viral RNA, whereas α4β7⁺ CD8 T cells correlated inversely, implicating impaired CD8 TEM recruitment in elevated parenchymal viral burden. In mice, α4 proved dispensable for CD4 trafficking to inflamed brain but essential for CD8 effector access across CNS compartments and for both subsets to reach skull marrow. These findings establish that α4 integrin governs CD8-mediated neuroimmune surveillance through coordinated cellular positioning, with blockade enabling viral seeding while disrupting spatially organized antiviral defense.
Authors
Pabitra B. Pal, Sonny R. Elizaldi, Giovanne B. Diniz, Ravi Prakash Rai, Yashavanth Shaan Lakshmanappa, Anil Verma, Daniel Rossmiller, Jesse Kaufman, Rahul Srivastava, Sean Ott, Carissa T. Erices, Kayla Schwartz, Danielle Beckman, Zhong-Min Ma, Alex Petkov, Daniel Newhouse, Dhivyaa Rajasundaram, John H. Morrison, Reben Raeman, Smita S. Iyer
Abstract
Metabolic-inflammatory crosstalk orchestrates muscle repair. Although pyroptosis typically aggravates sterile injury, we demonstrated that GSDME-dependent pyroptotic signaling associated with recruited myeloid cells paradoxically supported regeneration. GSDME expression was induced in post-surgical human muscle injury and murine damage models. Gsdme deficiency delayed functional recovery and exacerbated injury-induced myosteatosis, a pathological form of intramuscular ectopic fat deposition. Time-series and single-cell RNA-sequencing analyses revealed that GSDME loss shifted the transcriptional program from oxidative metabolism toward lipid storage and adipogenesis. Lipidomics confirmed aberrant accumulation of triacylglycerols and sphingolipids in Gsdme-deficient muscle. Single-cell profiling further identified divergent fibro-adipogenic progenitors (FAPs) states skewed toward adipogenesis, accompanied by impaired expansion of restorative Lyve1⁺Cd163⁺Txnip⁺ tissue-resident macrophages (TRMs)—validated by multiplex flow cytometry. Blocking CCR2-dependent monocyte recruitment produced regenerative defects comparable to those caused by Gsdme deficiency. Myeloid-specific Gsdme reintroduction rescued TRM expansion and function, curbed FAP adipogenic reprogramming, whereas FAP-specific expression proved ineffective. Mechanistically, IL-18 downstream of GSDME-dependent signaling engaged KLF4/JUN signaling in TRMs, sustaining their reparative and lipid-clearing capacity. This GSDME–IL-18–TRMs axis was compromised in aged muscle, yet exogenous IL-18 reversed myosteatosis and accelerated regeneration. Together, these findings suggest that GSDME-dependent pyroptotic signaling can act as a metabolic checkpoint that sustains TRM-driven lipid homeostasis to support muscle regeneration.
Authors
Qi Cao, Jian Liu, Gang Huang, Su-Yuan Wang, Guo-Dong Lu, Yong Huang, Yi-Ting Chen, Zhen Zhang, Jiang-Tao Fu, Si-Jia Sun, Xiaofei Chen, Chunlin Zhuang, Chunquan Sheng, Fu-Ming Shen, Dong-Jie Li, Pei Wang
Abstract
Interstitial lung disease (ILD) is a major cause of morbidity and mortality in systemic sclerosis (SSc); however, the immunopathologic mechanisms driving lung disease in SSc are unclear. T cells have been implicated as a likely driver of lung injury in SSc. Here, we have evaluated T cells in the blood of patients with SSc-ILD and identified a specific population of cytotoxic CD8 T cells that is expanded in SSc-ILD patients. Cytotoxic effector memory CD8 T cells marked by CD57 expression are preferentially expanded in SSc-ILD patients compared to SSc patients without ILD and controls and show prominent clonal expansion. These CD57+ T effector memory (TEM) cells differ from T effector memory cells re-expressing CD45RA (TEMRA) transcriptomically and functionally, with cytotoxic function that is enhanced by CD155 engagement of the costimulatory receptor CD226. We performed immunostaining of lung tissue samples obtained from independent SSc-ILD patients (biopsy or explant) and confirmed the presence of CD57+ TEM. In parallel, we analyzed publicly available lung scRNA-seq datasets from multiple ILD cohorts and identified endothelial cells as a likely source of CD155 to activate CD57+ cytotoxic T cells. Together, the results implicate a CD57+ cytotoxic CD8 T cell population as a potential mediator of lung injury in SSc-ILD.
Authors
Takanori Sasaki, Ye Cao, John M. Sowerby, Kazuhiko Higashioka, Kathryne E. Marks, Mehreen Elahee, Mari Kamiya, Paul F. Dellaripa, Richard I. Ainsworth, Kimberly E. Taylor, Nunzio Bottini, Paul Wolters, Edy Y. Kim, Francesco Boin, Deepak A. Rao
Abstract
Single-cell analysis of human triple-negative breast cancer revealed heterogeneous macrophage populations with opposing phenotypes—pro-inflammatory and pro-resolution of inflammation. Paradoxically, both subsets accumulated in therapy-refractory residual tumors but showed inverse correlations across patients, suggesting mutually exclusive resistance mechanisms. Inflammatory macrophages localized preferentially to epithelial-like tumors, whereas pro-resolution macrophages were enriched in mesenchymal-like tumors. Mouse models faithfully recapitulated these patterns. After immuno-chemotherapy, mesenchymal-like tumors expanded pro-resolution macrophages through phagocytosis/efferocytosis, ω-3 fatty-acid uptake, and resolvin production. Macrophage-secreted C1q emerged as a principal antagonist of T-cell function by targeting mitochondria and inducing metabolic dysfunction. By contrast, epithelial-like tumors accumulated inflammatory macrophages and neutrophils that produced prostaglandins via ω-6 fatty-acid pathways. Knocking down ELOVL5—an elongase involved in ω-3 and ω-6 metabolism—mitigated both neutrophil- and macrophage-mediated immunosuppression. These distinct axes, driven by dysregulated inflammation and resolution programs, converged to undermine therapy-induced immunosurveillance; however, targeting their shared upstream regulators may overcome these resistance mechanisms.
Authors
Liqun Yu, Charlotte Rivas, Fengshuo Liu, Yichao Shen, Ling Wu, Zhan Xu, Yunfeng Ding, Xiaoxin Hao, Weijie Zhang, Hilda L. Chan, Jun Liu, Bo Wei, Yang Gao, Luis Becerra-Dominguez, Yi-Hsuan Wu, Siyue Wang, Tobie D. Lee, Xuan Li, Xiang Chen, David G. Edwards, Xiang H.-F. Zhang
Abstract
Authors
Jana Blazkova, Brooke D. Kennedy, Jesse S. Justement, Victoria Shi, Adeline Sewack, Maegan R. Manning, Sonali S. Dasari, Kathleen Gittens, Susan Moir, Mark Connors, Stephen A. Migueles, Tae-Wook Chun
Abstract
Radiation therapy (RT) is the standard of care for glioblastoma but is not curative. Triggering the cGAS/stimulator of interferon genes (STING) pathway with potent agonists, such as 8803, exerts activity across high-grade glioma preclinical models. To determine if the combination of 8803 with RT warrants consideration in the up-front treatment setting and to clarify the underlying mechanisms of therapeutic activity, C57BL/6J mice harboring intracerebral CT-2A or QPP8v gliomas were treated with RT, intratumoral 8803, or both. The treatment with the combination resulted in 80% long-term survival in the CT-2A model but not in the radiation-resistant QPP8v model. This therapeutic effect was maintained in Sting–/– CT-2A cells, highlighting the direct role of the immune system in mediating the survival benefit. Single-cell RNA-Seq identified increased nitric oxide synthase 2 (Nos2) in inflammatory tumor-associated macrophages; however, the therapeutic effect was maintained in Nos2–/– mice. Additionally, 8803 reprogrammed the blood-brain barrier (BBB) by altering the Pecam and Cd147 pathways in endothelial cells; intracranial injection of 8803 induced bihemispheric BBB opening for up to 24 hours. Sting activation was visualized longitudinally using 3’-deoxy-3’-[18F]-fluorothymidine ([18F]-FLT) PET, which peaked 72–96 hours after 8803 administration. In summary, 8803 combined with RT triggers distinctive antiglioma immune reactivity, facilitates BBB opening, and warrants consideration for up-front clinical trials in glioblastoma, where treatment effects can be monitored using [18F]-FLT PET imaging.
Authors
Shashwat Tripathi, Hinda Najem, Lisa Hurley, Ruochen Du, Crismita Dmello, Heba Ali, Kathleen McCortney, Karl J. Habashy, Peng Zhang, Craig M. Horbinski, Lara Leoni, Ryan J. Avery, Rimas V. Lukas, Timothy L. Sita, David R. Raleigh, Sean Sachdev, Roger Stupp, Maciej S. Lesniak, David M. Ashley, Daniele Procissi, Michael A. Curran, Irina Balyasnikova, Amy B. Heimberger
Abstract
Anaphylaxis is a life-threatening hypersensitivity reaction. Clinical observations suggest heightened susceptibility during viral infections, yet the mechanisms remain poorly defined. Here, we show that both active and passive IgG-mediated anaphylaxis were exacerbated in the setting of acute viral infection. In mice, this enhancement was driven predominantly by FcγRIV, the homolog of human FcγRIIIa. FcγRIV crosslinking induced anaphylactic symptoms selectively in infected animals, with no effect in naive conditions. Among leukocytes, inflammatory monocytes emerged as the principal drivers of this lethal reaction. Viral infection triggered a strong upregulation of FcγRIV on inflammatory monocytes, an effect absent in type I IFN receptor–deficient (Ifnar1-deficient) mice. Extending these findings, we observed increased frequencies of CD16-expressing classical monocytes in patients with acute COVID-19, and murine SARS-CoV-2 infection recapitulated this phenotype. Mechanistically, FcγRIV crosslinking during infection promoted the production of platelet-activating factor, the key mediator of mortality, in a type I IFN–dependent (IFN-I–dependent) manner. Together, these findings indicate that viral infection creates an immune milieu that heightens monocyte sensitivity to Fcγ receptor engagement, positioning these cells as major effectors of IgG-mediated hypersensitivity in the infected host. They further suggest that Fc receptor pathway modulation merits further investigation in contexts with heightened IFN-I responses, such as in systemic lupus erythematosus.
Authors
Abdelrahman Elwy, Hossam Abdelrahman, Julia Specht, Gina M. Ewert, Justa Friebus-Kardash, Swati Dhiman, Julia Falkenstein, Theresa Charlotte Christ, Elisa Wiebeck, Arzoo Shamoon, Nils B. Leimkühler, Thomas Gramberg, Alina Russ, Ulrich Kalinke, Fei Kuang, Kathrin Sutter, Manfred Kopf, Matthias Mack, Wiebke Hansen, Falk Nimmerjahn, Karl S. Lang
Abstract
Broadly neutralizing antibodies (bnAbs) are evaluated as possible alternatives to standard antiretroviral treatment (ART) for maintaining control of HIV-1 replication and may enhance immune responses to reduce or control the viral reservoir. However, the immunological and virological effects of bnAbs in infants and children are unknown. We conducted a detailed analysis of proviral reservoir dynamics and antiviral immune responses in a unique group of young children from Botswana who started ART at birth and then stopped standard ART while receiving the bnAbs 10-1074 and VRC01-LS in a subsequent clinical trial. No quantitative changes in frequencies of proviral sequences were observed during bnAb treatment, but selection of genome-intact proviruses in transcriptionally repressive heterochromatin regions occurred in some study participants. Faster viral rebound following standard ART cessation was linked to elevated proportions of KIR2DL1-positive NK cells. In contrast, delayed viral rebound and more limited viral reservoir size were associated with elevated proportions of NKG2A-positive NK cells and with the HLA-B-21M signal peptide polymorphism. HIV-specific T cell responses were low in all study participants and unrelated to viral reservoir sizes or clinical outcomes following ART interruption. These results suggest that, in young children, specific NK cell subsets and KIR-HLA interactions might be linked to HIV-1 rebound kinetics after substitution of standard ART with bnAbs.
Authors
Aischa Niesar, Melanie Lancien, Seohyun Hong, Chloe Naasz, Gbolahan Ajibola, Kenneth Maswabi, Maureen Sakoi-Mosetlhi, Oganne Batlang, Sikhulile Moyo, Terence Mohammed, Comfort Maphorisa, Leah Carrere, Isabelle Roseto, Ciputra Adijaya Hartana, Toong Seng Tan, Ce Gao, Elizabeth Parsons, Renee Hua, Molly Pretorius Holme, Shahin Lockman, Kathleen M. Powis, Mary Carrington, Joseph Makhema, Xu G. Yu, Daniel R. Kuritzkes, Roger L. Shapiro, Mathias Lichterfeld
Abstract
BACKGROUND. Susceptibility to human immunodeficiency virus type 1 (HIV-1) infection varies between individuals, but the biological determinants of acquisition risk remain poorly defined. METHODS. We conducted a case-control study nested within a high-risk cohort in Kenya. We compared the plasma extracellular RNA collected before HIV-1 acquisition with matched uninfected controls to identify immunological processes linked to infection risk. RESULTS. Individuals who later acquired HIV-1 exhibited upregulation of immune processes that facilitate viral infection, including T cell suppression, type II interferon and Th2 immune responses. In contrast, processes associated with antiviral defence and tissue repair, such as neutrophil and natural killer cell responses, type I interferon responses, wound healing, and angiogenesis, were downregulated. CONCLUSION. These findings highlight dampened antiviral immunity prior to exposure as a correlate of increased risk for subsequent HIV-1 acquisition. TRIAL NUMBERS. Not applicable. FUNDING. This work was supported by a Wellcome Trust Award (209289/Z/17/Z) and the Sub-Saharan African Network for TB/HIV Research Excellence (SANTHE) through the DELTAS Africa programme [Del-22-007], supported by the Science for Africa Foundation, Wellcome Trust, the UK Foreign, Commonwealth & Development Office, and the European Union. Additional support was provided by the Bill & Melinda Gates Foundation, Gilead Sciences Inc., Aidsfonds, and the Ragon Institute of Mass General, MIT, and Harvard. The cohort study was supported by PEPFAR through USAID. The views expressed are those of the authors.
Authors
Mwikali Kioko, Shaban Mwangi, Lynn Fwambah, Amin S. Hassan, Jason T. Blackard, Philip Bejon, Eduard J. Sanders, Thumbi Ndung'u, Eunice W. Nduati, Abdirahman I. Abdi
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ISSN: 0021-9738 (print), 1558-8238 (online)