Effector Memory Research Articles

PRDM1 is a key regulator of the natural killer T–cell central memory program and effector function

Abstract Natural killer T cells (NKTs) are a promising platform for cancer immunotherapy, but few genes involved in regulation of NKT therapeutic activity have been identified. To find regulators of NKT functional fitness, we developed a CRISPR/Cas9-based mutagenesis screen that employs a guide RNA (gRNA) library targeting 1,118 immune-related genes. Unmodified NKTs and NKTs expressing a GD2-specific chimeric antigen receptor (GD2.CAR) were transduced with the gRNA library and exposed to CD1d+ leukemia or CD1d–GD2+ neuroblastoma cells, respectively, over six challenge cycles in vitro. Quantification of gRNA abundance revealed enrichment of PRDM1-specific gRNAs in both NKTs and GD2.CAR NKTs, a result that was validated through targeted PRDM1 knockout. Transcriptional, phenotypic, and functional analyses demonstrated that CAR NKTs with PRDM1 knockout underwent central memory–like differentiation and resisted exhaustion. However, these cells downregulated the cytotoxic mediator granzyme B and showed reduced in vitro cytotoxicity and only moderate in vivo antitumor activity in a xenogeneic neuroblastoma model. In contrast, shRNA-mediated PRDM1 knockdown preserved effector function while promoting central memory differentiation, resulting in GD2.CAR NKTs with potent in vivo antitumor activity. Thus, we have identified PRDM1 as a regulator of NKT memory differentiation and effector function that can be exploited to improve the efficacy of NKT-based cancer immunotherapies.

Transcriptional signature of CD56bright NK cells predicts favourable prognosis in bladder cancer

Human natural killer (NK) cells can be sub-divided into two functional subsets but the clinical significance of these CD56bright and CD56dim NK cells in anti-tumour immunity remains largely unexplored. We determined the relative abundances of gene signatures for CD56bright and CD56dim NK cells along with 3 stromal and 18 other immune cell types in the patient tumour transcriptomes from the cancer genome atlas bladder cancer dataset (TCGA-BLCA). Using this computational approach, CD56bright NK cells were predicted to be the more abundant tumour-infiltrating NK subset which was also associated with improved patient prognosis. A similar favorable survival trend was projected using gene signatures for mature myeloid dendritic cells (mDC) and CD8+ effector memory T cells (TEM) and unveiled a potential CD56bright NK-mDC-CD8+T cell crosstalk in the BLCA tumour microenvironment. Expression of transcripts encoding the activating NK cell receptors, NKG2D, NKp44, CD2, and CD160, showed positive survival trends in combination with CD56bright NK cell infiltration. Transcription factors including HOBIT, IRF3, and STAT2 were also correlated with CD56bright NK cell abundance. Additionally, a HOBIT-dependent tissue-residency program correlated with the CD56bright NK and CD8+ TEM cell signatures was found to be associated with favourable BLCA patient survival. Overall, our study highlights the significance of CD56bright NK cells in BLCA patient prognosis. Our findings facilitate a better understanding of the NK cell anti-tumour responses that may ultimately lead to the development of promising NK and T cell-based therapies for BLCA.

Chromatin landscape alteration uncovers multiple transcriptional circuits during memory CD8+ T cell differentiation.

Extensive epigenetic reprogramming involves in memory CD8+ T-cell differentiation. The elaborate epigenetic rewiring underlying the heterogeneous functional states of CD8+ T cells remains hidden. Here, we profile single-cell chromatin accessibility and map enhancer-promoter interactomes to characterize the differentiation trajectory of memory CD8+ T cells. We reveal that under distinct epigenetic regulations, the early activated CD8+ T cells divergently originated for short-lived effector and memory precursor effector cells. We also uncover a defined epigenetic rewiring leading to the conversion from effector memory to central memory cells during memory formation. Additionally, we illustrate chromatin regulatory mechanisms underlying long-lasting versus transient transcription regulation during memory differentiation. Finally, we confirm the essential roles of Sox4 and Nrf2 in developing memory precursor effector and effector memory cells, respectively, and validate cell state-specific enhancers in regulating Il7r using CRISPR-Cas9. Our data pave the way for understanding the mechanism underlying epigenetic memory formation in CD8+ T-cell differentiation.

Specific immune response to M. tuberculosis and ability to in vitro control mycobacterial replication are not impaired in subjects with immune-mediated inflammatory disease and tuberculosis infection

BackgroundSubjects with immune-mediated inflammatory diseases (IMID), such as rheumatoid arthritis, with tuberculosis infection (TBI), have a high probability of progressing to tuberculosis disease (TB). We aim to characterize the impact of IMID on the immune response to M. tuberculosis (Mtb) in patients with TBI and TB disease.MethodsWe enrolled TBI and TB patients with and without IMID. Peripheral blood mononuclear cells (PBMCs) were stimulated with Mtb-derived epitopes (MTB300). By flow-cytometry, we identified the Mtb-specific CD4+ T cells as cytokine-producing T cells or as CD25+ CD134+ CD4+ T cells. Memory and activation status of Mtb-specific T cells were assessed by evaluating: CD153, HLA-DR, CD45RA, CD27. Mycobacterial growth inhibition assay (MGIA) was used to evaluate the ability of PBMCs to inhibit mycobacteria growth. A long-term stimulation assay was used to detect a memory response.ResultsThe IMID status and therapy did not affect the magnitude of response to Mtb-antigen stimulation and the number of responders. TBI-IMID showed a cytokine profile like TBI and TB patients. The Mtb response of TBI-IMID patients was characterized by an effector memory and central memory phenotype as in TBI and TB groups. This memory phenotype allowed the increased IFN-γ production after 6 days of MTB300-stimulation. HLA-DR expression on Mtb-specific T cells was associated with TB, whereas CD153 was associated with TBI status. Finally, the TBI-IMID had an MGIA response like TBI and TB patients.ConclusionIMID condition does not affect key aspects of the immune response to Mtb, such as the cytokine response, memory and activation profile, and the ability to contain the mycobacteria replication. The immunological characterization of the fragile population of TBI-IMID patients is fundamental to understanding the correlation between protection and disease.

A distinct immunophenotype in children carrying the Blautia enterotype: The generation R study.

Studies in mouse models and human adults have shown that the intestinal microbiota composition can affect peripheral immune cells. We here examined whether the gut microbiota compositions affect B and T-cell subsets in children. The intestinal microbiota was characterized from stool samples of 344 10-year-old children from the Generation R Study by performing 16S rRNA sequencing. Bray-Curtis dissimilarity was used to cluster distinct microbiome compositions (enterotypes). B-cell and T-cell phenotypes were defined by 11-color-flow cytometry. Linear regression models with adjustment for lifestyle and child characteristics were performed to determine associations between enterotypes and immune cell numbers. Three enterotypes with distinct microbiota composition were found, characterized by high abundance of Prevotella, Bacteroides and Blautia. Children with the Blautia enterotype had decreased numbers of plasmablasts, CD4+ central memory (Tcm) T cells and follicular T-helper cells (Tfh), while Th22 cells and CD4+ effector memory (Tem) T cells, CD27-IgA+ memory B cells and CD27-IgE+ memory B cells, were increased in these children. In addition, in children with the Blautia enterotype CD4+ Tcm cell numbers expressing the β7 integrin, which can pair with α4 to mediate intestinal were also lower, while CD4+β7+ Tem cell numbers were higher than in the other enterotypes. The Blautia enterotype showed features beneficial for human health. Enterotypes were associated with differences in memory B- and T-cell compartments. This study is unique in the detailed analysis of the B and T-cell compartment and the intestinal microbiome in a large generic pediatric cohort, enabling correction for child and maternal covariates. These outcomes could guide further studies about the impact of intestinal microbiome intervention, for instance through diet and microbiota metabolites such as short chain fatty acid production.

Circular mRNA Vaccine against SARS-COV-2 Variants Enabled by Degradable Lipid Nanoparticles.

The emergence of mRNA vaccines offers great promise and a potent platform in combating various diseases, notably COVID-19. Nevertheless, challenges such as inherent instability and potential side effects of current delivery systems underscore the critical need for the advancement of stable, safe, and efficacious mRNA vaccines. In this study, a robust mRNA vaccine (cmRNA-1130) eliciting potent immune activation has been developed from a biodegradable lipid with eight ester bonds in the branched tail (AX4) and synthetic circular mRNA (cmRNA) encoding the trimeric Delta receptor binding domain of the SARS-CoV-2 spike protein. Notably, the cmRNA-1130 vaccine exhibits outstanding stability, remaining effective after six months of storage at 4 °C and multiple freeze-thaw cycles. In comparison with the commercial MC3 lipid, the nanoparticles formed from the degradable AX4 lipid revealed a much faster metabolic rate from the liver and spleen, affording negligible impairment to the hepatorenal function. Following intramuscular administration, cmRNA-1130 generates robust and sustained neutralizing antibodies and induces the activation of Delta RBD-specific CD4+ and CD8+ T effector memory cells (TEM) and Th1-biased T cells in mice. Featured with potent immune activation, high stability, and decent safety, vaccines formed from cmRNA and AX4 hold a huge clinical potential for the prophylaxis and treatment of different diseases.

Polyfunctional CD8+CD226+RUNX2hi effector Tcells are diminished in advanced stages of chronic lymphocytic leukemia.

CD8+ Tcells, a subset of Tcells identified by the surface glycoprotein CD8, particularly those expressing the co-stimulatory molecule CD226, play a crucial role in the immune response to malignancies. However, their role in chronic lymphocytic leukemia (CLL), an immunosuppressive disease, has not yet been explored. We studied 64 CLL patients and 25 age- and sex-matched healthy controls (HCs). We analyzed the proportion of CD226-expressing cells among different CD8+ Tcell subsets (including naïve, central memory, effector memory, and effectors) in CLL patients, stratified by Rai stage and immunoglobulin heavy-chain variable region gene (IgHV) mutation status. Additionally, we compared the effector functions of CD8+CD226+ cells and their CD226- counterparts. We also quantified cytokine and chemokine levels in the plasma of CLL and HCs. Furthermore, we reanalyzed the publicly available bulk RNA-seq on CD226+ and CD226-CD8+ Tcells. Finally, we evaluated the impact of elevated cytokines/chemokines on CD226 expression. Our results showed that CD226-expressing cells were significantly decreased within the effector memory and effector CD8+ Tcell subsets in CLL patients with advanced Rai stages and unmutated IgHV, a marker of poor prognosis. These cells displayed robust effector functions, including cytokine production, cytolytic activity, degranulation, proliferation, and migration capacity. In contrast, CD8+CD226- Tcells displayed an exhausted phenotype with reduced Runt-related transcription factor 2 (RUNX2) expression. Elevated levels of interleukin-6 (IL-6) and macrophage inflammatory protein-1 beta (MIP-1β) were inversely correlated with the frequency of CD8+CD226+ Tcells and may contribute to the downregulation of CD226, possibly leading to Tcell dysfunction in CLL. Our findings highlight the critical role of CD8+CD226+RUNX2hi Tcells in CLL and suggest that their reduction is associated with disease progression and poor clinical outcomes. This study also underscores the potential of targeting IL-6 and MIP-1β to preserve polyfunctional CD8+CD226+ Tcells as a promising immunotherapy strategy.

Subunit protein CD40.SARS.CoV2 vaccine induces SARS-CoV-2-specific stem cell-like memory CD8+ T cells

Ideally, vaccination should induce protective long-lived humoral and cellular immunity. Current licensed COVID-19 mRNA vaccines focused on the spike (S) region induce neutralizing antibodies that rapidly wane. Herein, we show that a subunit vaccine (CD40.CoV2) targeting spike and nucleocapsid antigens to CD40-expressing cells elicits broad specific human (hu)Th1 CD4+ and CD8+ T cells in humanized mice. CD40.CoV2 vaccination selectively enriched long-lived spike- and nucleocapsid-specific CD8+ progenitors with stem-cell-like memory (Tscm) properties, whereas mRNA BNT162b2 induced effector memory CD8+ T cells. CD8+ Tscm cells produced IFNγ and TNF upon antigenic restimulation and showed a high proliferation rate. We demonstrate that CD40 activation is specifically required for the generation of huCD8+ Tscm cells. These results support the development of a CD40-vaccine platform capable of eliciting long-lasting T-cell immunity. This work was supported by Inserm, Université Paris-Est Créteil, and the Investissements d'Avenir program, Vaccine Research Institute (VRI), managed by the ANR.

Bioinformatics-Based Analysis and Verification of Chromatin Regulators and the Mechanism of Immune Infiltration Associated with Myocardial Infarction.

Recent studies have shown that dysfunction in chromatin regulators (CRs) may be an important mechanism of myocardial infarction (MI). They are thus expected to become a new target in the diagnosis and treatment of MI. However, the diagnostic value of CRs in MI and the mechanisms are not clear. CRs-related differentially expressed genes (DEGs) were screened between healthy controls and patients with MI via GSE48060, GSE60993, and GSE66360 datasets. DEGs were further analyzed for enrichment analysis. Hub genes were screened by least absolute shrinkage and selection operator (LASSO) regression and weighted gene co-expression network analysis (WGCNA). GSE61144 datasets were further used to validate hub genes. RT-qPCR examined peripheral blood mononuclear cells (PBMCs) to verify expressions of hub genes. In addition, a correlation between hub genes and immune cell infiltration was identified by CIBERSORT and single-sample gene set enrichment analysis (ssGSEA). Finally, we constructed a diagnostic nomogram and ceRNA network and found possible therapeutic medicines which were based on hub genes. Firstly, 16 CR-related DEGs were identified. Next, Dual-specificity phosphatase 1 (DUSP1), growth arrest and DNA damage-inducible 45 (GADD45A), and transcriptional regulator Jun dimerization protein 2 (JDP2) were selected as hub genes by LASSO and WGCNA. Receiver operating characteristic curves in the training and test data sets verified the reliability of hub genes. Results of RT-qPCR confirmed the upregulation of hub genes in MI. Subsequently, the immune infiltration analysis indicated that DUSP1, GADD45A, and JDP2 were correlated with plasmacytoid dendritic cells, natural killer cells, eosinophils, effector memory CD4 T cells, central memory CD4 T cells, activated dendritic cells, and activated CD8 T cells. Furthermore, a nomogram that included DUSP1, GADD45A, and JDP2 was created. The calibration curve, decision curve analysis, and the clinical impact curve indicated that the nomogram could predict the occurrence of MI with high efficacy. The results of the ceRNA network suggest that hub genes may be cross-regulated by various lncRNAs and miRNAs. In addition, 10 drugs, including 2H-1-benzopyran, Nifuroxazide, and Bepridil, were predicted to be potential therapeutic agents for MI. Our study identifies three promising genes associated with the progression of chromatin regulators (CRs)-related myocardial infarction (MI) and immune cell infiltration, including Dual-specificity phosphatase 1 (DUSP1), growth arrest and DNA damage-inducible 45 (GADD45A), and Jun dimerization protein 2 (JDP2), which might be worthy of further study.

Depletion of regulatory T cells enhances the T cell response induced by the neoantigen vaccine with weak immunogenicity.

The neoantigen vaccine has remarkable potential in treating advanced cancer due to its tumor specificity and ability to bypass central tolerance mechanisms. However, numerous neoantigens show poor immunogenicity, and the immune inhibitory factors of present in both tumors and tumor-draining lymph nodes impair the efficacy of cancer neoantigen vaccine. Eliminating immunosuppressive cells will improve the priming and expansion of anti-tumor immune cells induced by the vaccine. In this study, a Treg-depleting regimen (consisting of CD25mAb and low-dose cyclophosphamide (LD-CTX)) was used in conjunction with a neoantigen vaccine for treating mice with solid tumors. We constructed two types of tumor models and investigated differences in therapy efficacy in the four groups (PBS, vaccine, CD25mAb+CTX and combination) at the genetic and protein levels. ELISPOT and TCR sequencing were applied to detect the expansion of neoantigen reactive T cells (NRT) and tumor antigen spreading. In the combinational group, the ELISPOT results showed an obvious expansion of NRT cells induced by weak immunogenic peptides. The combinational group exhibited significant improvement in inhibiting the tumor growth extended the survival time of tumor-bearing mice, and promoted T cells infiltration into tumors. Besides, compared to the Vac group, more neoantigen-targeted and TAA-targeted T cells were detected in the combinational group by TCR sequencing. The results of transcriptomic sequencing and flow cytometry showed that the number of Tregs in the combinational group was lower, while the proportions of memory effector T cells and effector T cells were higher than those in the vaccine group. An increase in mature DCs was also observed in vaccinated mice after receiving this Treg-depleting strategy. Our research first revealed that inhibiting the normal function of Tregs transformed "weaker" neoantigens into "stronger" ones, while also contributing to the proliferation of NRT cells. This Treg-depleting strategy allowed neoantigens with poor immunogenicity to elicit a robust immune response, thereby augmenting the efficacy of the neoantigen vaccine in delaying tumor growth and prolonging the survival of the hosts.

Enhancing antibody levels and T cell activity of quadrivalent influenza vaccine by combining it with CpG HP021

Influenza virus infections are a serious danger to people’s health worldwide as they are responsible for seasonal flu outbreaks. There is an urgent need to improve the effectiveness and durability longevity of the immune response to influenza vaccines. We synthesized the CpG HP021 and examined the impact of it on the immune response to an influenza vaccine. In BALB/c mice, hemagglutination inhibition (HI) titers to the vaccine were increased four- to eightfold against H1N1, H3N2, BV, and BY viruses by 3 μg IIV4 + 40 μg CpG HP021 compared with those of the non-adjuvanted IIV4 group, and the CpG HP021 group had a broader HI activity. Additionally, the immune response was directed towards Type 1 T helper (Th1) cells due to the CpG HP021 adjuvant. The CpG HP021-adjuvanted IIV4 induced a higher number of T cells secreting interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α), and increased the percentage of effector memory T cells in mice. In SD rats, the immune responses induced by IIV4 with CpG HP021 were similar to those in BALB/c mice. The development of CpG HP021 may expand the options for adjuvants in vaccines against infectious diseases.

CD57+ EMRA CD8+ T cells in cancer patients over 70: associations with prior chemotherapy and response to anti-PD-1/PD-L1 therapy

BackgroundImmune ageing complicates cancer treatment in older individuals. While immunotherapy targeting the PD-1/PD-L1 pathway can reinvigorate T cells, these cells tend to become senescent with age. This study investigates different CD8+ T cell subsets usually associated with senescence, in cancer patients over 70 years old who are undergoing anti-PD-1/PD-L1 immunotherapy, and examines the relationship between these senescent cells and prior chemotherapy exposure. We analyzed data from the Elderly Cancer Patient (ELCAPA) cohort, which included 35 patients enrolled between March 2018 and March 2021.ResultsFlow cytometry and unsupervised analysis were employed to characterize Effector Memory CD45RA+ (EMRA) and CD8+ T cell senescence at baseline, before initiating PD-1/PD-L1 therapy. EMRA cells were found to overexpress CD57 and KLRG1 compared to overall CD8+ T cells. Chemotherapy prior to anti-PD-1/PD-L1 was associated with an increased proportion of CD57+ EMRA CD8+ T cells (p = 0.009) and its granzyme B (GRZB) subset (p = 0.007). Using a 10% cut-off to define positivity, the six-month non-response tends to be associated with the CD57+ GRZB+ EMRA positivity (p = 0.097). Other CD8+ T cell subsets (EMRA, CD57+, or KLRG1+), usually associated with senescence, showed no significant association with previous chemotherapy or response to anti-PD-1/anti-PD-L1 therapy.ConclusionsThese findings underscore the impact of prior chemotherapy on expanding the pool of senescent T cells, particularly CD57+ EMRA CD8+ T and CD57+ GRZB+ EMRA CD8+ T cells, whose expansion could potentially affect the effectiveness of anti-PD-1/PD-L1 immunotherapy in elderly patients. This highlights the need for tailored approaches in this population.

Deciphering long-term immune effects of HIV-1/SARS-CoV-2 co-infection: a longitudinal study

IntroductionWhile the general immune response to Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) is well-understood, the long-term effects of Human Immunodeficiency Virus-1/Severe Acute Respiratory Syndrome-Coronavirus-2 (HIV-1/SARS-CoV-2) co-infection on the immune system remain unclear. This study investigates the immune response in people with HIV-1 (PWH) co-infected with SARS-CoV-2 to understand its long-term health consequences.MethodsA retrospective longitudinal study of PWH with suppressed viral load and SARS-CoV-2 infection was conducted. Cryopreserved peripheral blood mononuclear cells and plasma samples were collected at three time-points: HIV-1/pre-SARS-CoV-2 (n = 18), HIV-1/SARS-CoV-2 (n = 46), and HIV-1/post-SARS-CoV-2 (n = 36). Plasma levels of 25 soluble cytokines and chemokines, and anti-S/anti-N-IgG-SARS-CoV-2 antibodies were measured. Immunophenotyping of innate and adaptive immune components and HIV-1 and SARS-CoV-2-specific T/B-cell responses were assessed by flow cytometry.ResultsHIV-1/SARS-CoV-2 co-infection was associated with long-lasting immune dysfunction, characterized by elevated levels of pro-inflammatory cytokines and a decrease in the MIG-IP10-ITAC chemokine axis at the HIV/SARS-CoV-2 time-point, which persisted one year later. Additionally, alterations in the distribution of subsets and increased activation (NKG2D/NKG2C) and maturation (TIM3) markers of NK and dendritic cells were observed at the HIV-1/SARS-CoV-2 time-point, persisting throughout the study. Effector memory CD4 T-cell subsets were decreased, while exhaustion/senescence (PD1/TIM3/CD57) markers were elevated at all three time-points. SARS-CoV-2-specific T/B-cell responses remained stable throughout the study, while HIV-1-specific T-cell responses decreased at the HIV-1/SARS-CoV-2 time-point and remained so.ConclusionsPersistent immune dysfunction in HIV-1/SARS-CoV-2 co-infection increases the risk of future complications, even in PWH with mild symptoms. Exacerbated inflammation and alterations in immune cells may contribute to reduce vaccine efficacy and potential reinfections.

Activated/Cycling Treg Deficiency and Mitochondrial Alterations in Immunological Non-Responders to Antiretroviral Therapy.

Regulatory T-cells (Tregs) play a crucial role in maintaining immune homeostasis, but their dynamics are altered in a subset of people living with Human Immunodeficiency Virus (HIV) known as immunological non-responders (INRs). INRs fail to reconstitute CD4+ T-cell counts despite viral suppression. This study aimed to examine Treg dysregulation in INRs, comparing them to immunological responders (IRs) and healthy controls (HCs). The study included 40 INRs, 42 IRs, and 23 HCs. Peripheral blood mononuclear cells were isolated and analyzed by flow cytometry. Conventional CD4+ T-cells (Tconvs) were identified as CD25-/loFOXP3- cells, while Tregs were identified as CD25+CD127loFOXP3+ CD4+ T-cells. Cells were further divided into naive, central memory, effector memory, and effector memory cells re-expressing CD45RA (TEMRA) subsets. Activated/cycling cells were identified as CD71+ and quiescent cells were CD71-. Mitochondrial mass and transmembrane potential were measured using MitoTracker Green and MitoTracker Orange dyes, respectively. Statistical comparisons were made using the Kruskal-Wallis test with Dunn's post-hoc analysis and Mann-Whitney U-test. INRs exhibited the highest frequencies of activated/cycling CD4+ T-cells. The proportion of activated/cycling cells was higher in Tregs compared to Tconvs in all groups. Cycling rates of Tregs and Tconvs were correlated, suggesting Tregs help control Tconv proliferation. Despite high overall Treg frequencies in INRs, they showed a Treg deficiency in activated/cycling CD4+ T-cells, specifically in naive and central memory subsets, causing an imbalance in the Tconv/Treg ratio. This deficiency was hidden by increased Treg frequencies in quiescent effector memory CD4+ T-cells. Activated/cycling naive and memory Tregs from INRs had normal forkhead box P3 (FOXP3) and CD25 expression, but activated/cycling memory Tregs showed decreased ability to regulate mitochondrial transmembrane potential, indicating impaired mitochondrial fitness. These mitochondrial abnormalities were similar to those observed in memory conventional T-cells. The complex Treg dysregulation in immunological non-responders involves quantitative and functional alterations, including a Treg deficiency within activated/cycling naive and central memory CD4+ T-cells, impaired mitochondrial fitness of activated/cycling memory Tregs, and functional disorders of the parent conventional T-lymphocytes. These findings underscore the need for a nuanced understanding of Treg dynamics in suboptimal CD4+ T-cell reconstitution during HIV-infection.

Type I interferon and mitochondrial dysfunction are associated with dysregulated cytotoxic CD8+ T cell responses in juvenile systemic lupus erythematosus

Abstract Juvenile systemic lupus erythematosus (JSLE) is an autoimmune condition which causes significant morbidity in children and young adults and is more severe in its presentation than adult-onset SLE. While many aspects of immune dysfunction have been studied extensively in adult-onset SLE, there is limited and contradictory evidence of how cytotoxic CD8+ T cells contribute to disease pathogenesis and studies exploring cytotoxicity in JSLE are virtually non-existent. Here, we report that CD8+ T cell cytotoxic capacity is reduced in JSLE versus healthy controls, irrespective of treatment or disease activity. Transcriptomic and serum metabolomic analysis identified that this reduction in cytotoxic CD8+ T cells in JSLE was associated with upregulated type I interferon (IFN) signalling, mitochondrial dysfunction, and metabolic disturbances when compared to controls. Greater interrogation of the influence of these pathways on altered cytotoxic CD8+ T cell function demonstrated that JSLE CD8+ T cells had enlarged mitochondria and enhanced sensitivity to IFN-α leading to selective apoptosis of effector memory (EM) CD8+ T cells, which are enriched for cytotoxic mediator-expressing cells. This process ultimately contributes to the observed reduction in CD8+ T cell cytotoxicity in JSLE, reinforcing the growing evidence that mitochondrial dysfunction is a key pathogenic factor affecting multiple immune cell populations in type I IFN-driven rheumatic diseases.

How do immune cells shape type 1 diabetes? Insights from Mendelian randomization.

The role of immune cells in type 1 diabetes (T1D) is unclear. The aim of this study was to assess the causal effect of different immune cells on T1D using Mendelian randomization (MR). A dataset of immune cell phenotypes (numbered from GCST0001391 to GCST0002121) was obtained from the European Bioinformatics Institute, while a T1D dataset (numbered finngen_R10_T1D) was obtained from FinnGen. Single nucleotide polymorphisms meeting the conditions were screened stepwise according to the assumptions of association, independence, and exclusivity. Inverse variance weighted was used as the main method for the MR analysis. MR-Egger was used to assess the horizontal pleiotropy of the results. Cochran's Q and the leave-one-out method were respectively used for the heterogeneity analysis and the sensitivity analysis of the results. MR analysis showed that effector memory (EM) double-negative (DN) (CD4-CD8-) %T cells [odds ratio (OR) = 1.157, 95% confidence interval (95% CI) = 1.016-1.318, p = 0.028, false discovery rate (FDR) = 0.899], EM CD8br %T cells (OR = 1.049, 95% CI = 1.003-1.098, p = 0.037, FDR = 0.902), CD28 on CD28+CD45RA+CD8br (OR = 1.334, 95% CI = 1.132-1.571, p = 0.001, FDR = 0.044), IgD+CD38dim %lymphocytes (OR = 1.045, 95% CI = 1.002-1.089, p = 0.039, FDR = 0.902), CD80 on monocytes (OR = 1.084, 95% CI = 1.013-1.161, p = 0.020, FDR = 0.834), SSC-A on plasmacytoid dendritic cells (pDCs) (OR = 1.174, 95% CI = 1.004-1.372, p = 0.044, FDR = 0.902), and FSC-A on pDCs (OR = 1.182, 95% CI = 1.011-1.382, p = 0.036, FDR = 0.902) were associated with an increased genetic susceptibility to T1D. Cochran's Q showed that there was heterogeneity for CD28 on the CD28+CD45RA+CD8br results (p = 0.043), whereas there was no heterogeneity for the other results (p ≥ 0.05). The sensitivity analysis showed that the MR analysis results were robust. The MR analysis demonstrated that seven immune cell phenotypes were associated with an increased genetic susceptibility to T1D. These findings provide a new direction for the pathogenesis of and the drug development for T1D.

Targeting ACAT1 for Precision Chemo‐Immunoprevention in Lung Cancer

AbstractLung cancer (LC) is a leading cause of cancer‐related deathworldwide, and altered cholesterol metabolism is a hallmark of cancer cells. Acyl‐CoA:cholesterol acyltransferase 1(ACAT1), or Sterol O‐acyltransferase 1 (SOAT1), isa key cholesterol esterification enzyme. Its overexpression promotes tumorprogression by accumulating cholesterol esters. Inhibition of ACAT1 also potentiatesCD8+ T cells medicated anti‐tumor immunity by increasing plasma membranecholesterol level. This study, as the first of its kind, shows the ACAT1/SOAT1 overexpressioncorrelates with poor prognosis in early‐stage lung adenocarcinoma (LUAD) patients.Long‐term treatment with ACAT1 inhibitor avasimibe suppresses tumorigenesis inboth Kirsten rat sarcoma viral oncogene homolog (KRAS) and epidermal growthfactor receptor (EGFR) mutation‐induced LC mouse models without overttoxicity. ACAT1 inhibition reduces tumor cell proliferation, migration, andinvasion and causes G0/G1 cell cycle arrest, while boosting CD8+ T cells'effector function and memory phenotype. Single‐cell RNA sequencing reveals thatACAT1 inhibition downregulates cholesterol biosynthesis and central carbon andnitrogen metabolism pathways in tumor cells, while upregulating genes relatedto oxidative phosphorylation and fatty acid oxidation in CD8+ T cells. Finally, avasimibe improves the efficacy of a human EGFR vaccine in preventing LCprogression. These novel findings suggest potential strategies for cancer preventionand therapy.

Coupling of response biomarkers between tumor and peripheral blood in patients undergoing chemoimmunotherapy.

Platinum-based chemotherapy in combination with anti-PD-L1 antibodies has shown promising results in mesothelioma. However, the immunological mechanisms underlying its efficacy are not well understood and there are no predictive biomarkers to guide treatment decisions. Here, we combine time course RNA sequencing (RNA-seq) of peripheral blood mononuclear cells with pre-treatment tumor transcriptome data from the single-arm, phase 2 DREAM trial (N= 54). Single-cell RNA-seq and Tcell receptor sequencing (TCR-seq) reveal that CD8+ T effector memory (TEM) cells with stem-like properties are more abundant in peripheral blood of responders and that this population expands upon treatment. These peripheral blood changes are linked to the transcriptional state of the tumor microenvironment. Combining information from both compartments, rather than individually, is most predictive of response. Our study highlights complex interactions between the tumor and immune cells in peripheral blood during objective tumor responses to chemoimmunotherapy. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12616001170415.

Patterns and cofactors of polyfunctional mycobacteria-specific T cell response restoration following 6-month antiretroviral treatment in children living with HIV.

Despite immune restoration after initiation of antiretroviral treatment (ART), the risk of tuberculosis (TB) persists in children living with HIV (CLHIV). We determined patterns of immune restoration of mycobacteria-specific T cells following ART in CLHIV. CD4 and CD8 T cell activation and memory phenotype and functional profiles before and 6 months after ART were evaluated in peripheral blood mononuclear cells (PBMCs) from CLHIV enrolled in the PUSH study (NCT02063880) in Nairobi, Kenya. T cell expression of cytokines and activation induced markers (AIM) were measured following stimulation of PBMCs with a pool of 300 peptides from TB (MTB300) or staphylococcal enterotoxin B (SEB). Among 47 CLHIV of median age 1.5 years, SEB-induced Th1 cytokine+ and AIM+ CD4 cell frequencies increased significantly after 6 months ART. Although MTB300-specific CD4 and CD8 cell frequency did not increase after ART, polyfunctional capacity of MTB300-specific CD4 cells expressing combinations of Th1 cytokines with CD40L increased significantly after ART. Baseline age, immune activation, and effector memory CD4 levels were associated with less restoration of MTB300-specific polyfunctional CD4 cells, whereas CD4% and levels of naïve CD4 cells following ART were associated with improved MTB300-specific polyfunctional capacity. Despite increases in Th1 cytokine production, deficits in mycobacteria-specific CD4 cells persisted 6 months after ART, with higher deficits in older CLHIV with more immunosuppression, higher immune activation, and lower proportion of naïve CD4 cells. These findings may explain persistent TB risk during early ART among CLHIV and identify those at highest risk.

Enhancing protective immunity against SARS-CoV-2 with a self-amplifying RNA lipid nanoparticle vaccine.

RNA-based vaccines against SARS-CoV-2 have demonstrated promising protective immunity against the global COVID-19 epidemic. Enhancing the intensity and duration of mRNA antigen expression is anticipated to markedly boost antiviral immune responses. Self-amplifying RNA (saRNA) represents a next-generation platform for RNA-based vaccines, amplifying transcripts in situ to augment the expression of encoded immunogens. Here, we develop a saRNA nanovaccine, formulated with a mutated saRNA encoding the receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein, encapsulated within a lipid nanoparticle (LNP-saRNA-RBD). This LNP-saRNA vaccine platform enables efficient delivery of saRNA-RBD, inducing enhanced and prolonged expression of the RBD antigen. LNP-saRNA-RBD vaccination stimulated the generation of antigen-specific T cells, promoting their differentiation into a long-lived effector memory phenotype. Immunization with LNP-saRNA-RBD induced a germinal center response in draining lymph nodes, leading to the production of anti-RBD IgG antibodies with the ability to neutralize SARS-CoV-2 pseudovirus. Furthermore, prime-boost immunizations with LNP-saRNA-RBD conferred protection to mice against SARS-CoV-2 challenge by suppressing viral infection and replication, as well as pulmonary inflammatory responses and associated damage. Taken together, these findings provide strong support for advancing the development of LNP-saRNA-RBD as a safe and efficacious vaccine candidate against SARS-CoV-2 infection.