Immunologies
Abstract
Maternal SARS-CoV-2 infection triggers placental inflammation and alters cord blood immune cell composition. However, most studies focus on outcomes of severe maternal infection. Therefore, we analyzed cord blood and chorionic villi from newborns of unvaccinated mothers who experienced mild/asymptomatic SARS-CoV-2 infection during pregnancy. We investigated immune cell rewiring using flow cytometry, single-cell RNA sequencing, and functional readouts using ex vivo stimulation with TLR agonists and pathogens. Maternal infection was associated with increased frequency of memory T- and B-cells, and non-classical monocytes in cord blood. Ex vivo T- and B-cell responses to stimulation were attenuated, suggesting a tolerogenic state. Maladaptive responses were also observed in cord blood monocytes, where antiviral responses were dampened but responses to bacterial TLRs were increased. Maternal infection was also associated with expansion and activation of placental Hofbauer cells, secreting elevated levels of myeloid cell recruiting chemokines. Moreover, we reported increased activation of maternal-derived monocytes/macrophages in the fetal placenta that are transcriptionally primed for antiviral responses. Our data indicate that even in the absence of vertical transmission or symptoms in the neonate, mild/asymptomatic maternal COVID-19 altered the transcriptional and functional state in fetal immune cells in circulation and in the placenta.
Authors
Brianna M. Doratt, Suhas Sureshchandra, Heather True, Monica Rincon, Nicole E. Marshall, Ilhem Messaoudi
Abstract
Pathogenic mutations in mitochondrial (mt) tRNA genes that compromise oxidative phosphorylation (OXPHOS) exhibit heteroplasmy and cause a range of multisyndromic conditions. Although mitochondrial disease patients are known to suffer from abnormal immune responses, how heteroplasmic mtDNA mutations affect the immune system at the molecular level is largely unknown. Here, in mice carrying pathogenic C5024T in mt-tRNAAla and in patients with mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS) syndrome carrying A3243G in mt-tRNALeu, we found memory T and B cells to have lower pathogenic mtDNA mutation burdens than their antigen-inexperienced naive counterparts, including after vaccination. Pathogenic burden reduction was less pronounced in myeloid compared with lymphoid lineages, despite C5024T compromising macrophage OXPHOS capacity. Rapid dilution of the C5024T mutation in T and B cell cultures could be induced by antigen receptor–triggered proliferation and was accelerated by metabolic stress conditions. Furthermore, we found C5024T to dysregulate CD8+ T cell metabolic remodeling and IFN-γ production after activation. Together, our data illustrate that the generation of memory lymphocytes shapes the mtDNA landscape, wherein pathogenic variants dysregulate the immune response.
Authors
Jingdian Zhang, Camilla Koolmeister, Jinming Han, Roberta Filograna, Leo Hanke, Monika Àdori, Daniel J. Sheward, Sina Teifel, Shreekara Gopalakrishna, Qiuya Shao, Yong Liu, Keying Zhu, Robert A. Harris, Gerald McInerney, Ben Murrell, Mike Aoun, Liselotte Bäckdahl, Rikard Holmdahl, Marcin Pekalski, Anna Wedell, Martin Engvall, Anna Wredenberg, Gunilla B. Karlsson Hedestam, Xaquin Castro Dopico, Joanna Rorbach
Abstract
Maternal decidual CD8+ T cells must integrate the antithetical demands of providing immunity to infection while maintaining immune tolerance for fetal and placental antigens. Human decidual CD8+ T cells were shown to be highly differentiated memory T cells with mixed signatures of dysfunction, activation, and effector function. However, no information is present on how specificity for microbial or fetal antigens relates to their function or dysfunction. In addition, a key question, whether decidual CD8+ T cells include unique tissue-resident memory T cells (Trm) or also effector memory T cell (Tem) types shared with peripheral blood populations, is unknown. Here, high-dimensional flow cytometry of decidual and blood CD8+ T cells identified 2 Tem populations shared in blood and decidua and 9 functionally distinct Trm clusters uniquely found in decidua. Interestingly, fetus- and virus-specific decidual CD8+ Trm cells had similar features of inhibition and cytotoxicity, with no significant differences in their expression of activation, inhibitory, and cytotoxic molecules, suggesting that not all fetus-specific CD8+ T cell responses are suppressed at the maternal-fetal interface. Understanding how decidual CD8+ T cell specificity relates to their function and tissue residency is crucial in advancing understanding of their contribution to placental inflammation and control of congenital infections.
Authors
Shweta Mahajan, Aria Alexander, Zachary Koenig, Nicholas Saba, Nina Prasanphanich, David A. Hildeman, Claire A. Chougnet, Emily DeFranco, Sandra Andorf, Tamara Tilburgs
Abstract
Pyrin, a protein encoded by the MEFV gene, plays a vital role in innate immunity by sensing modifications in Rho GTPase and assembling the pyrin inflammasome, which in turn activates downstream immune responses. We identified a novel and de novo MEFV p.E583A dominant variant in three patients from a family, distinct from the previously reported S242 and E244 sites. These patients exhibited a phenotype that diverged from those resulting from classical MEFV gene mutations, characterized by the absence of recurrent fever but the presence of recurrent chest and abdominal pain. Colchicine effectively controlled the phenotype, and the mutation was found to induce pyrin inflammasome assembly and activation in patients' peripheral blood mononuclear cells (PBMCs) and cell lines. Mechanistically, truncation experiments revealed that the E583A variant impacted the autoinhibitory structure of pyrin. Our study offers new insights into the mechanisms underlying pyrin inflammasome activation.
Authors
Qintao Wang, Taijie Jin, Shan Jian, Xu Han, Hongmei Song, Qing Zhou, Xiaomin Yu
Abstract
Regulatory T cells (Tregs) expressing Chimeric Antigen Receptors (CARs) are a promising tool to promote transplant tolerance. The relationship between CAR structure and Treg function was studied in xenogeneic, immunodeficient mice, revealing advantages of CD28-encoding CARs. However, these models could underrepresent interactions between CAR-Tregs, antigen-presenting cells (APCs) and donor-specific antibodies. We generated Tregs expressing HLA-A2-specific CARs with different costimulatory domains and compared their function in vitro and in vivo using an immunocompetent model of transplantation. In vitro, the CD28-encoding CAR had superior antigen-specific suppression, proliferation and cytokine production. In contrast, in vivo, Tregs expressing CARs encoding CD28, ICOS, PD1 and GITR, but not 41BB or OX40, all extended skin allograft survival. To reconcile in vitro and in vivo data, we analyzed effects of a CAR encoding CD3ζ but no co-stimulatory domain. These data revealed that exogenous co-stimulation from APCs can compensate for the lack of a CAR-encoded CD28 domain. Thus, Tregs expressing a CAR with or without CD28 are functionally equivalent in vivo, mediating similar extension of skin allograft survival and controlling the generation of anti-HLA-A2 alloantibodies. This study reveals a new dimension of CAR-Treg biology and has important implications for the design of CARs for clinical use in Tregs.
Authors
Isaac Rosado-Sánchez, Manjurul Haque, Kevin Salim, Madeleine Speck, Vivian C.W. Fung, Dominic A. Boardman, Majid Mojibian, Giorgio Raimondi, Megan K. Levings
Abstract
Engineered cytokine-based approaches for immunotherapy of cancer are poised to enter the clinic, with IL-12 being at the forefront. However, little is known about potential mechanisms of resistance to cytokine therapies. We found that orthotopic murine lung tumors were resistant to systemically delivered IL-12 fused to murine serum albumin (MSA, IL12-MSA) due to low IL-12R expression on tumor-reactive CD8+ T cells. IL2-MSA increased binding of IL12-MSA by tumor-reactive CD8+ T cells, and combined administration of IL12-MSA and IL2-MSA led to enhanced tumor-reactive CD8+ T cell effector differentiation, decreased numbers of tumor-infiltrating CD4+ regulatory T (Treg) cells, and increased survival of lung tumor-bearing mice. Predictably, the combination of IL-2 and IL-12 at therapeutic doses led to significant dose-limiting toxicity. Administering IL-12 and IL-2 analogs with preferential binding to cells expressing IL12rb1 and CD25, respectively, led to a significant extension of survival in mice with lung tumors while abrogating dose-limiting toxicity. These findings suggest that IL-12 and IL-2 represent a rational approach to combination cytokine therapy whose dose-limiting toxicity can be overcome with engineered cytokine variants.
Authors
Brendan L. Horton, Alicia D. D'Souza, Maria Zagorulya, Chloe V. McCreery, Gita C. Abhiraman, Lora K. Picton, Allison Sheen, Yash Agarwal, Noor Momin, Karl Dane Wittrup, Forest M. White, K. Christopher Garcia, Stefani Spranger
Abstract
CD8+ T cells can recognize tumor antigens displayed by HLA class I molecules and eliminate tumor cells. Despite their low tumor mutation burden, immune checkpoint blockade (ICB) is often beneficial in patients with renal cell carcinoma (RCC). Here, using a proteogenomic approach, we directly and comprehensively explored the HLA class I–presenting peptidome of RCC tissues and demonstrated that the immunopeptidomes contain a small subset of peptides derived from human endogenous retroviruses (hERV). A comparison between tumor and normal kidney tissues revealed tumor-associated hERV antigens, one of which was immunogenic and recognized by host tumor-infiltrating lymphocytes (TIL). Stimulation with the hERV antigen induced reactive CD8+ T cells in healthy donor–derived (HD-derived) peripheral blood mononuclear cells (PBMC). These results highlight the presence of antitumor CD8+ T cell surveillance against hERV3895 antigens, suggesting their clinical applications in patients with RCC.
Authors
Shin Kobayashi, Serina Tokita, Keigo Moniwa, Katsuyuki Kitahara, Hiromichi Iuchi, Kazuhiko Matsuo, Hidehiro Kakizaki, Takayuki Kanaseki, Toshihiko Torigoe
Abstract
The endosomal Toll-like receptor 7 (TLR7) is a major driver of murine and human systemic lupus erythematosus (SLE). The role of TLR7 in lupus pathogenesis is enhanced when the regulatory role of TLR9 is absent. TLR7 signaling in plasmacytoid DCs (pDC) is generally thought to be a major driver of the IFN response and disease pathology; however, the cell types in which TLR7 acts to mediate disease have not been distinguished. To address this, we selectively deleted TLR7 in either CD11c+ cells or CD19+ cells; using a TLR7-floxed allele, we created on the lupus-prone MRL/lpr background, along with a BM chimera strategy. Unexpectedly, TLR7 deficiency in CD11c+ cells had no impact on disease, while TLR7 deficiency in CD19+ B cells yielded mild suppression of proteinuria and a trend toward reduced glomerular disease. However, in TLR9-deficient MRL/lpr mice with accelerated SLE, B cell–specific TLR7 deficiency greatly improved disease. These results support revision of the mechanism by which TLR7 drives lupus and highlight a cis regulatory interaction between the protective TLR9 and the pathogenic TLR7 within the B cell compartment. They suggest B cell–directed, dual TLR7 antagonism/TLR9 agonism or dual TLR7/9 antagonism as a potential future therapeutic strategy to treat SLE.
Authors
Haylee A. Cosgrove, Sebastien Gingras, Minjung Kim, Sheldon Bastacky, Jeremy S. Tilstra, Mark J. Shlomchik
Abstract
Risk of severe disease and death due to COVID-19 is increased in certain patient demographic groups, including those of advanced age, male sex, and obese body mass index. Investigations of the biological variations that contribute to this risk have been hampered by heterogeneous severity, with immunologic features of critical disease potentially obscuring differences between risk groups. To examine immune heterogeneity related to demographic risk factors, we enrolled 38 patients hospitalized with clinically homogeneous COVID-19 pneumonia — defined as oxygen saturation less than 94% on room air without respiratory failure, septic shock, or multiple organ dysfunction — and performed single-cell RNA-Seq of leukocytes collected at admission. Examination of individual risk factors identified strong shifts within neutrophil and monocyte/dendritic cell (Mo/DC) compartments, revealing altered immune cell type–specific responses in higher risk COVID-19 patient subgroups. Specifically, we found transcriptional evidence of altered neutrophil maturation in aged versus young patients and enhanced cytokine responses in Mo/DCs of male versus female patients. Such innate immune cell alterations may contribute to outcome differences linked to these risk factors. They also highlight the importance of diverse patient cohorts in studies of therapies targeting the immune response in COVID-19.
Authors
Allison C. Billi, Rachael Wasikowski, Feiyang Ma, Srilakshmi Yalavarthi, Claire K. Hoy, Yu Zuo, Matthew T. Patrick, Neha Shah, Christine Parker, Chad Aaronson, Alyssa Harbaugh, Matthew F. Lucido, Kerby Shedden, Krishna Rao, Heidi B. IglayReger, Charles F. Burant, J. Michelle Kahlenberg, Lam C. Tsoi, Johann E. Gudjonsson, Jason S. Knight, Yogendra Kanthi
Abstract
Systemic lupus erythematosus (SLE) affects 1 in 537 Black women, which is >2-fold more than White women. Black patients develop the disease at a younger age, have more severe symptoms, and have a greater chance of early mortality. We used a multiomics approach to uncover ancestry-associated immune alterations in patients with SLE and healthy controls that may contribute biologically to disease disparities. Cell composition, signaling, epigenetics, and proteomics were evaluated by mass cytometry; droplet-based single-cell transcriptomics and proteomics; and bead-based multiplex soluble mediator levels in plasma. We observed altered whole blood frequencies and enhanced activity in CD8+ T cells, B cells, monocytes, and DCs in Black patients with more active disease. Epigenetic modifications in CD8+ T cells (H3K27ac) could distinguish disease activity level in Black patients and differentiate Black from White patient samples. TLR3/4/7/8/9-related gene expression was elevated in immune cells from Black patients with SLE, and TLR7/8/9 and IFN-α phospho-signaling and cytokine responses were heightened even in immune cells from healthy Black control patients compared with White individuals. TLR stimulation of healthy immune cells recapitulated the ancestry-associated SLE immunophenotypes. This multiomic resource defines ancestry-associated immune phenotypes that differ between Black and White patients with SLE, which may influence the course and severity of SLE and other diseases.
Authors
Samantha Slight-Webb, Kevin Thomas, Miles Smith, Catriona A. Wagner, Susan Macwana, Aleksandra Bylinska, Michele Donato, Mai Dvorak, Sarah E. Chang, Alex Kuo, Peggie Cheung, Laurynas Kalesinskas, Ananthakrishnan Ganesan, Denis Dermadi, Carla J. Guthridge, Wade DeJager, Christian Wright, Mariko H. Foecke, Joan T. Merrill, Eliza Chakravarty, Cristina Arriens, Holden T. Maecker, Purvesh Khatri, Paul J. Utz, Judith A. James, Joel M. Guthridge
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