Human T cells coordinate adaptive immunity in diverse anatomic compartments through production of cytokines and effector molecules, but it is unclear how tissue site influences T cell persistence and ...function. Here, we use single cell RNA-sequencing (scRNA-seq) to define the heterogeneity of human T cells isolated from lungs, lymph nodes, bone marrow and blood, and their functional responses following stimulation. Through analysis of >50,000 resting and activated T cells, we reveal tissue T cell signatures in mucosal and lymphoid sites, and lineage-specific activation states across all sites including distinct effector states for CD8
T cells and an interferon-response state for CD4
T cells. Comparing scRNA-seq profiles of tumor-associated T cells to our dataset reveals predominant activated CD8
compared to CD4
T cell states within multiple tumor types. Our results therefore establish a high dimensional reference map of human T cell activation in health for analyzing T cells in disease.
Immune response dynamics in coronavirus disease 2019 (COVID-19) and their severe manifestations have largely been studied in circulation. Here, we examined the relationship between immune processes ...in the respiratory tract and circulation through longitudinal phenotypic, transcriptomic, and cytokine profiling of paired airway and blood samples from patients with severe COVID-19 relative to heathy controls. In COVID-19 airways, T cells exhibited activated, tissue-resident, and protective profiles; higher T cell frequencies correlated with survival and younger age. Myeloid cells in COVID-19 airways featured hyperinflammatory signatures, and higher frequencies of these cells correlated with mortality and older age. In COVID-19 blood, aberrant CD163+ monocytes predominated over conventional monocytes, and were found in corresponding airway samples and in damaged alveoli. High levels of myeloid chemoattractants in airways suggest recruitment of these cells through a CCL2-CCR2 chemokine axis. Our findings provide insights into immune processes driving COVID-19 lung pathology with therapeutic implications for targeting inflammation in the respiratory tract.
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•Airways show localized immune responses correlating to age and outcome in COVID-19•Airway T cells are activated and resident, while myeloid cells are hyperinflammatory•Aberrant CD163hi and HLA-DRlo monocytes predominate in COVID-19 blood•Monocytes infiltrate airways and lung alveoli potentially through a CCL2-CCR2 axis
Through longitudinal profiling of paired airways and blood from patients with severe COVID-19, Szabo et al. reveal airway immune responses that correlate with age and outcome. They further identify coordinate roles for T and myeloid cells in the respiratory tract and circulation in perpetuating lung pathology and disease pathogenesis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Antigen-independent homeostasis of memory CD8 T cells is vital for sustaining long-lived T cell-mediated immunity. In this study, we report that maintenance of human memory CD8 T cell effector ...potential during in vitro and in vivo homeostatic proliferation is coupled to preservation of acquired DNA methylation programs. Whole-genome bisulfite sequencing of primary human naive, short-lived effector memory (T
), and longer-lived central memory (T
) and stem cell memory (T
) CD8 T cells identified effector molecules with demethylated promoters and poised for expression. Effector-loci demethylation was heritably preserved during IL-7- and IL-15-mediated in vitro cell proliferation. Conversely, cytokine-driven proliferation of T
and T
memory cells resulted in phenotypic conversion into T
cells and was coupled to increased methylation of the CCR7 and Tcf7 loci. Furthermore, haploidentical donor memory CD8 T cells undergoing in vivo proliferation in lymphodepleted recipients also maintained their effector-associated demethylated status but acquired T
-associated programs. These data demonstrate that effector-associated epigenetic programs are preserved during cytokine-driven subset interconversion of human memory CD8 T cells.
The thymus is a central lymphoid organ primarily responsible for the development of T cells. A small proportion of B cells, however, also reside in the thymus to assist negative selection of ...self-reactive T cells. Here we show that the thymus of human neonates contains a consistent contingent of CD138
plasma cells, producing all classes and subclasses of immunoglobulins with the exception of IgD. These antibody-secreting cells are part of a larger subset of B cells that share the expression of signature genes defining mouse B1 cells, yet lack the expression of complement receptors CD21 and CD35. Data from single-cell transcriptomic, clonal correspondence and in vitro differentiation assays support the notion of intrathymic CD138
plasma cell differentiation, alongside other B cell subsets with distinctive molecular phenotypes. Lastly, neonatal thymic plasma cells also include clones reactive to commensal and pathogenic bacteria that commonly infect children born with antibody deficiency. Thus, our findings point to the thymus as a source of innate humoral immunity in human neonates.
IL-15 has shown preclinical activity by enhancing the functional maturation of natural killer (NK) cells. Clinical evaluation of the potential anticancer activity of most cytokines, including IL-15, ...has been limited by low tolerability and rapid
clearance. Efbalropendekin Alfa (XmAb24306) is a soluble IL15/IL15-receptor alpha heterodimer complex fused to a half-life extended Fc domain (IL15/IL15Rα-Fc), engineered with mutations to reduce IL-15 affinity for CD122. Reduced affinity drives lower potency, leading to prolonged pharmacodynamic response in cynomolgus monkeys. We show that
, human NK cells treated with XmAb24306 demonstrate enhanced cytotoxicity against various tumor cell lines. XmAb24306-treated NK cells also exhibit enhanced killing of 3D colorectal cancer spheroids. Daratumumab (dara), a monoclonal antibody (mAb) that targets CD38 results in antibody-dependent cellular cytotoxicity (ADCC) of both multiple myeloma (MM) cells and NK cells. Addition of XmAb24306 increases dara-mediated NK cell ADCC against various MM cell lines
. Because NK cells express CD38, XmAb24306 increases dara-mediated NK cell fratricide, but overall does not negatively impact the ADCC activity against a MM cell line likely due to increased NK cell activity of the surviving cells. These data show that XmAb24306 increases direct and ADCC-mediated human NK cell cytotoxicity
.
Non-recirculating tissue-resident memory T cells (TRMs) are the predominant T cell subset in diverse tissue sites, where they mediate protective immune responses in situ. Here, we reveal a role for ...TRM in maintaining immune homeostasis in the human pancreas through interactions with resident macrophages and the PD-1/PD-L1 inhibitory pathway. Using tissues obtained from organ donors, we identify that pancreas T cells comprise CD8+PD-1hi TRMs, which are phenotypically, functionally, and transcriptionally distinct compared to TRMs in neighboring jejunum and lymph node sites. Pancreas TRMs cluster with resident macrophages throughout the exocrine areas; TRM effector functions are enhanced by macrophage-derived co-stimulation and attenuated by the PD-1/PD-L1 pathways. Conversely, in samples from chronic pancreatitis, TRMs exhibit reduced PD-1 expression and reduced interactions with macrophages. These findings suggest important roles for PD-1 and TRM-macrophage interactions in controlling tissue homeostasis and immune dysfunctions underlying inflammatory disease, with important implications for PD-1-based immunotherapies.
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•The human pancreas contains CD8+ TRMs exhibiting tissue-specific molecular signatures•Pancreas TRMs express high levels of PD-1 yet maintain strong effector function•During homeostasis, pancreas TRMs are regulated by PD-L1+ tissue macrophages•In chronic pancreatitis, TRM PD-1 levels and PD-L1+ macrophage density are reduced
Non-recirculating tissue-resident memory T cells (TRMs) mediate immune responses in non-lymphoid tissues. Using a human organ donor tissue resource, Weisberg et al. reveal that PD-1hi pancreas TRMs are regulated by PD-L1+ macrophages during homeostasis. Comparison with chronic pancreatitis patient samples shows how pancreas TRM regulation is altered during inflammation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Adaptive immune responses to SARS-CoV-2 infection have been extensively characterized in blood; however, most functions of protective immunity must be accomplished in tissues. Here, we report from ...examination of SARS-CoV-2 seropositive organ donors (ages 10 to 74) that CD4
T, CD8
T, and B cell memory generated in response to infection is present in the bone marrow, spleen, lung, and multiple lymph nodes (LNs) for up to 6 months after infection. Lungs and lung-associated LNs were the most prevalent sites for SARS-CoV-2–specific memory T and B cells with significant correlations between circulating and tissue-resident memory T and B cells in all sites. We further identified SARS-CoV-2–specific germinal centers in the lung-associated LNs up to 6 months after infection. SARS-CoV-2–specific follicular helper T cells were also abundant in lung-associated LNs and lungs. Together, the results indicate local tissue coordination of cellular and humoral immune memory against SARS-CoV-2 for site-specific protection against future infectious challenges.
NLRP3 inflammasome in SK pathogenesis.
Herpes simplex 1 infection of the eye can cause blindness with lesions in the corneal stroma largely attributable to inflammatory events that include components ...of both adaptive and innate immunity. Several innate immune responses are triggered by herpes simplex 1, but it is unclear how such innate events relate to the subsequent development of stromal keratitis. In this study, we compared the outcome of herpes simplex 1 ocular infection in mice unable to express NLRP3 because of gene knockout (NLRP3−/−) to that of wild‐type mice. The NLRP3−/− mice developed more‐severe and earlier stromal keratitis lesions and had higher angiogenesis scores than did infected wild‐type animals. In addition, NLRP3−/− mice generated an increased early immune response with heightened chemokines and cytokines, including interleukin‐1β and interleukin‐18, and elevated recruitment of neutrophils. Increased numbers of CD4+ T cells were seen at later stages of the disease in NLRP3−/− animals. Reduction in neutrophils prevented early onset of the disease in NLRP3−/− animals and lowered levels of bioactive interleukin‐1β but did not lower bioactive interleukin‐18. In conclusion, our results indicate that NLRP3 has a regulatory and beneficial role in herpetic stromal keratitis pathogenesis.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Human cytomegalovirus (HCMV) infection can lead to congenital hearing loss and mental retardation. Upon immune suppression, reactivation of latent HCMV or primary infection increases morbidity in ...cancer, transplantation, and late stage AIDS patients. Current treatments include nucleoside analogues, which have significant toxicities limiting their usefulness. In this study we screened a panel of synthetic heparin-binding peptides for their ability to prevent CMV infection in vitro. A peptide designated, p5+14 exhibited ~ 90% reduction in murine CMV (MCMV) infection. Because negatively charged, cell-surface heparan sulfate proteoglycans (HSPGs), serve as the attachment receptor during the adsorption phase of the CMV infection cycle, we hypothesized that p5+14 effectively competes for CMV adsorption to the cell surface resulting in the reduction in infection. Positively charged Lys residues were required for peptide binding to cell-surface HSPGs and reducing viral infection. We show that this inhibition was not due to a direct neutralizing effect on the virus itself and that the peptide blocked adsorption of the virus. The peptide also inhibited infection of other herpesviruses: HCMV and herpes simplex virus 1 and 2 in vitro, demonstrating it has broad-spectrum antiviral activity. Therefore, this peptide may offer an adjunct therapy for the treatment of herpes viral infections and other viruses that use HSPGs for entry.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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