The Era of Cytotoxic CD4 T Cells

Enhanced Antitumor Immunity by ASP1570, a Novel Diacylglycerol Kinase ζ Inhibitor, Offers a Potential Novel Immunotherapy for Treating Cancer

Studies of diacylglycerol kinase ζ (DGKζ) in DGKζ knockout mice have revealed its role as an intracellular immune checkpoint in T cells. Although enhancing antitumor immunity by pharmacologic inhibition of DGKζ is desirable, selective DGKζ inhibitors for clinical use remain largely unexplored. In this study, we report a novel, small-molecule DGKζ inhibitor, ASP1570, which is currently under phase 1 development (NCT05083481), and characterize its effect on potential resistance mechanisms against approved immune checkpoint inhibitors in multiple immunosuppressive conditions: not only TGF-β, prostaglandin E2, adenosine, and PD-1 but also cytotoxic T-lymphocyte antigen-4 and T-cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory motif. First, our findings indicated that ASP1570 exhibited an inhibitory effect on the kinase activity of DGKζ. Unexpectedly, we observed that DGKζ protein was degraded in cells treated with ASP1570 in a proteasome-dependent manner. ASP1570 enhanced T-cell activation with increased diacylglycerol downstream signaling and released anergic T cells from their hyporesponsive state. Furthermore, ASP1570 restored T-cell functions suppressed by multiple immunosuppressive signals (TGF-β, prostaglandin E2, adenosine, PD-1, cytotoxic T-lymphocyte antigen-4, and T-cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory motif) and induced tumor growth inhibition in two types of syngeneic mouse models: anti-PD-1 antibody-sensitive MC38 and anti-PD-1 antibody-insensitive B16F1/F10. The antitumor efficacy of ASP1570 was canceled by CD8+ T-cell depletion, indicating that its antitumor effect depends on CD8+ cytotoxic T-cell activation. Collectively, ASP1570 potentially improves antitumor efficacy in both anti-PD-1 therapy-resistant and anti-PD-1 therapy-responsive tumors by overcoming multiple immunosuppressive signals.

Combining Single-Cell RNA Sequencing and Mendelian Randomization to Explore Novel Drug Targets for Parkinson's Disease

Neuroinflammation is a key pathological factor of PD, and T cells play a central role in neuroinflammatory progression. However, the causal effect of T cell-related genes on the risk of PD is still unclear. We explored single-cell RNA sequencing (scRNA-Seq) datasets of the peripheral blood T cells of PD patients and healthy controls, and screened the differentially expressed genes (DEGs) in the cytotoxic CD4 + T cells relative to the other T cell subsets. Pseudo-time series analysis, cell-cell communication analysis, and metabolic pathway analysis was performed for the cytotoxic CD4 + T cells. The DEGs were also functionally annotated through GO and KEGG pathway enrichment analyses. The MR approach was used to establish causal effects of the DEGs (exposure) on PD risk (outcome), and explore new drug targets for PD. The findings of MR analysis were further validated by Steiger filtering, bidirectional MR, Bayesian colocalization analysis, and phenotype scanning, and the GWAS data from an independent PD case-control cohort was used for external validation of the results. Finally, differences in gene expression between PD patients and healthy controls were further validated in scRNA-Seq and bulk transcriptome sequencing data. We found that increased expression of IL-32, GNLY, MT2A, and ARPC2 was significantly associated with a higher risk of PD. In contrast, the increase in ARRB2 was closely related to a lower risk of PD. IL32, GNLY, MT2A, ARRB2, and ARPC2 are the causal genes and potential drug targets of PD. Cytotoxic CD4 + T cells are likely the key effectors of PD-related neuroinflammation. These findings provide new insights into the pathogenesis and treatment options for PD, and further research and clinical trials based on the five potential drug targets and neuroinflammation are necessary.

Enhanced interpretation of immune cell phenotype and function through a rhesus macaque single-cell atlas

Single-cell RNA sequencing (scRNA-seq) allows cell classification using genome-wide transcriptional state; however, high-dimensional transcriptomic profiles, and the unsupervised analyses employed to interpret them, provide a systematically different view of biology than well-established functional/lineage definitions of immunocytes. Understanding these differences and limits is essential for accurate interpretation of these rich data. We present the Rhesus Immune Reference Atlas (RIRA), the first immune-focused macaque single-cell multi-tissue atlas. We contrasted transcriptional profiles against immune lineages, using surface protein and marker genes as ground truth. While the pattern of clustering can align with cell type, this is not always true. Especially within T and natural killer (NK) cells, many functionally distinct subsets lack defining markers, and strong shared expression programs, such as cytotoxicity, result in systematic intermingling by unsupervised clustering. We identified gene programs with high discriminatory/diagnostic value, including multi-gene signatures that model T/NK cell maturation. Directly measuring these diagnostic programs complements unsupervised analyses.

T cell immunophenotypes and IgE responses in patients with moderate-to-severe atopic dermatitis receiving dupilumab

BACKGROUND

Targeting the interleukin-4 receptor alpha (IL-4Rα) subunit has proven clinical efficacy in atopic dermatitis (AD).

OBJECTIVE

This study assessed the peripheral phenotype and function of T-cells, but also levels of total and sIgE and its receptors in AD patients receiving dupilumab.

METHODS

AD patients were clinically assessed (n = 75) and peripheral blood samples were taken (n = 25). Multiparametric flow cytometry was performed to characterize T-cell subsets (before treatment and 6 months later). Total and specific IgE were measured by ImmunoCap, soluble CD23 and FcεR1 in serum by ELISA, and eosinophils by differential blood analysis.

RESULTS

SCORing Atopic Dermatitis scores and body surface area involvement decreased upon treatment after 6 months of treatment to 67% and 77% from baseline. At the T cell level, we observed a 0.55-fold reduction of Th2-cells and a mean 27% increase in regulatory T-cells from baseline, accompanied by shifts towards Th1 and Th17 phenotypes. Furthermore, circulating CD4+CXCR5+TFH17 and CD4+CXCR5+TFH17.1 positive cells (mean 40% and 42%) and T-cell-specific IL-2 (+0.96-fold) and IL-10 (+1.96-fold) secretion increased, whereas IL-4 (mean -55%) and IL-17A (mean -27%) were reduced. Eosinophil counts (mean -22%), total IgE (mean -47%) and House Dust Mite sIgE (mean -40%) decreased, whereas CD23 and FcεR1 remained unchanged.

CONCLUSIONS

The T-cell and cytokine profiles during anti-IL4-Ra treatment suggest that targeting this pathway promotes a systemic shift of the T-cell compartment by reducing the T helper type 2 and complementary IgE responses. The sustainability of these disease-modifying effects requires further investigation.

Type I IFNs contribute to upregulation of PD-L1 during Chlamydia trachomatis infection

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that if left untreated can cause reproductive harm. Failure of natural adaptive immunity results in chronic and repeat infections. In efforts to understand the failure of adaptive immunity, we have previously discovered that CD8+ T cells, normally integral for controlling intracellular pathogen infections, are misprogrammed by PD-1/PD-L1 signaling during in vivo C. trachomatis infection and fail to mount a protective response. Seeking to uncover the pathways and host factors involved in PD-L1 upregulation that may lead to CD8+ T-cell inhibition, we discovered that C. trachomatis triggers the secretion of host type I interferons (IFNs) that are necessary and sufficient to upregulate PD-L1 in vitro. Additionally, secretion of type I IFNs is dependent on C. trachomatis development and its type III secretion system. We have also validated that type I IFNs contribute to upregulation of PD-L1 during C. trachomatis infection in vivo using a mouse model of infection. Overall, these findings reveal that C. trachomatis induction of this host pathway may contribute to adaptive immune evasion.

Neoantigen peptide-pulsed dendritic cell vaccine therapy after surgical treatment of pancreatic cancer: a retrospective study

Introduction

Pancreatic cancer shows very poor prognosis and high resistance to conventional standard chemotherapy and immunotherapy; therefore, the development of new breakthrough therapies is highly desirable.

Method

We retrospectively evaluated the safety and efficacy of neoantigen peptide-pulsed dendritic cell (Neo-P DC) vaccine therapy after surgical treatment of pancreatic cancer.

Result

The result showed induction of neoantigen-specific T cells in 13 (81.3%) of the 16 patients who received Neo-P DC vaccines. In survival analysis of the nine patients who received Neo-P DC vaccines after recurrence, longer overall survival was observed in patients with neoantigen-specific T cell induction than those without T cell induction. Notably, only one of the seven patients who received Neo-P DC vaccines as adjuvant setting developed recurrence, and no patient died during median follow-up 61 months after surgery (range, 25-70 months). Furthermore, TCR repertoire analyses were performed in a case treated with Neo-P DC vaccine combined with long and short peptides, and one significantly dominant clone induced by the long peptide was detected among CD4+ T cell populations.

Discussion

The present study suggests the feasibility and efficacy of Neo-P DC vaccine therapy after surgical treatment of pancreatic cancer in both postoperative recurrence cases and adjuvant setting. A case analysis suggests the importance of combination with long peptides targeting CD4+ T cell.

Enhancing immunity during ageing by targeting interactions within the tissue environment

Immunity declines with age. This results in a higher risk of age-related diseases, diminished ability to respond to new infections and reduced response to vaccines. The causes of this immune dysfunction are cellular senescence, which occurs in both lymphoid and non-lymphoid tissue, and chronic, low-grade inflammation known as 'inflammageing'. In this Review article, we highlight how the processes of inflammation and senescence drive each other, leading to loss of immune function. To break this cycle, therapies are needed that target the interactions between the altered tissue environment and the immune system instead of targeting each component alone. We discuss the relative merits and drawbacks of therapies that are directed at eliminating senescent cells (senolytics) and those that inhibit inflammation (senomorphics) in the context of tissue niches. Furthermore, we discuss therapeutic strategies designed to directly boost immune cell function and improve immune surveillance in tissues.

Single-cell RNA sequencing reveals potential therapeutic targets in the tumor microenvironment of lung squamous cell carcinoma

Lung squamous cell carcinoma (LUSC), accounting for 30% of lung cancer cases, lacks adequate research due to limited understanding of its molecular abnormalities. Our study analyzed public LUSC datasets to explore the tumor microenvironment (TME) composition using scRNA-seq from two cohorts. Applying non-negative matrix factorization, we identified unique malignant cell phenotypes, or meta-programs (MPs), based on gene expression patterns. Survival analysis revealed the clinical relevance of these MPs. Findings illuminated a TME landscape enriched with immune cells-CD8 + T, exhausted T, CD4 + T, and naive T cells-and suggested roles for myeloid cells, like cDC1 and pDCs, in LUSC progression. Different MPs highlighted the heterogeneity of malignant cells and their clinical implications. Targeting MP-specific genes may enable personalized therapy, especially for early-stage LUSC. This study offers insights into immune cell function in tumor dynamics, identifies MPs, and paves the way for novel LUSC strategies, enhancing early intervention, personalized treatment, and prognosis, ultimately improving patient outcomes.

CD4 T cells take center stage during dengue infection

Ansari et al.1 identified a subset of CD4 T cells (CXCR5-PD-1+) resembling T follicular helper (Tfh) cells in patients with severe dengue. This subset helps B cell responses via IL-21 and can also differentiate into cytotoxic CD4 T cells.

Lymph-Node Inspired Hydrogels Enhance CAR Expression and Proliferation of CAR T Cells

Chimeric antigen receptor (CAR) T therapy has shown unprecedented results in clinical practice, including long-term complete responses. One of the current challenges of CAR T therapy is to optimize its production in order to lower its cost. Currently, the in vivo activation of T cells by dendritic cells is replicated ex vivo using polymeric magnetic beads coated with antibodies to induce polyclonal T cell activation. However, current practice overlooks the importance of the complex environment that constitutes the lymph nodes, in which T cells activate and proliferate in vivo. Hydrogels are an ideal candidate material for mimicking the properties of natural tissues such as lymph nodes. In this study, key conditions of the composition, stiffness, and microarchitecture of hydrogels were experimentally and theoretically investigated to optimize primary human CAR T cell culture, focusing on CAR expression and proliferation. Poly(ethylene glycol)-heparin hydrogels featuring interconnected pores of 120 μm and an intermediate stiffness of 3.1 kPa were identified as the most suitable conditions for promoting CAR T cell expression and expansion. Specifically, these hydrogels increased the percentage of CAR+ cells by 50% and doubled the replication index compared to suspension cultures. In conclusion, these newly engineered hydrogels are an interesting tool to help improve CAR T cell manufacture and ultimately advance toward a broader clinical implementation of CAR T cell therapy.

Blood and tissue HIV-1 reservoirs display plasticity and lack of compartmentalization in virally suppressed people

Characterizing the HIV-1 reservoir in blood and tissues is crucial for the development of curative strategies. Using an HIV Tat mRNA-containing lipid nanoparticle (Tat-LNP) in combination with panobinostat, we show that p24+ cells from blood and lymph nodes exhibit distinct phenotypes. Blood p24+ cells are found in both central/transitional (TCM/TTM) and effector memory subsets, mostly lack CXCR5 expression and are enriched in GZMA+ cells. In contrast, most lymph node p24+ cells display a TCM/TTM phenotype, with approximately 50% expressing CXCR5 and nearly all lacking GZMA expression. Furthermore, germinal center T follicular helper cells do not appear to harbor the translation-competent reservoir in long-term suppressed individuals. Near full-length HIV-1 sequencing in longitudinal samples from matched blood, lymph nodes, and gut indicates that clones of infected cells, including those carrying an inducible provirus, persist and spread across various anatomical compartments. Finally, uniform genetic diversity across sites suggests the absence of ongoing replication in tissues under treatment.

Emerging insights into the gut microbiota as a key regulator of immunity and response to immunotherapy in hepatocellular carcinoma

The gut microbiota, a complex microbial ecosystem closely connected to the liver via the portal vein, has emerged as a critical regulator of liver health and disease. Numerous studies have underscored its role in the onset and progression of liver disorders, including alcoholic liver disease, metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction-associated steatohepatitis (MASH), liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). This review provides a comprehensive overview of current insights into the influence of the gut microbiota on HCC progression, particularly its effects on immune cells within the HCC tumor microenvironment (TME). Furthermore, we explore the potential of gut microbiota-targeted interventions, such as antibiotics, probiotics, prebiotics, and fecal microbiota transplantation (FMT), to modulate the immune response and improve outcomes of immunotherapy in HCC. By synthesizing insights from recent studies, this review aims to highlight microbiota-based strategies that may enhance immunotherapy outcomes, advancing personalized approaches in HCC treatment.

CX3CR1+ age-associated CD4+ T cells contribute to synovial inflammation in late-onset rheumatoid arthritis

BACKGROUND

Recent evidence suggests that clonally expanded cytotoxic T cells play a role in various autoimmune diseases. Late-onset rheumatoid arthritis (LORA) exhibits unique characteristics compared to other RA forms, suggesting distinct immunological mechanisms. This study aimed to examine the involvement of cytotoxic T cells in LORA.

METHODS

Fresh peripheral blood samples were collected from 78 treatment-naïve active RA patients, 12 with difficult-to-treat RA, and 16 healthy controls. Flow cytometry was employed to measure the proportions of CX3CR1+cytotoxic CD4+ and CD8+ T cells in these samples. Additionally, immunohistochemical staining was performed on lymphoid node and synovial biopsy samples from patients with RA.

RESULTS

CX3CR1+cytotoxic CD4+ T cells were specifically increased in untreated, active patients with LORA, displaying features of CXCR3mid age-associated T helper cells known as "ThA". CX3CR1⁺CD4⁺ T cells were identified as a cytotoxic ThA subset, as nearly all of these cells specifically expressed granzyme B. These cells were observed in enlarged lymph nodes and were found to infiltrate synovial tissues from patients with LORA. The proportions of CX3CR1+CD4+ T cells positively correlated with arthritis activity in LORA. The number of cells decreased after treatment with methotrexate, tumor necrosis factor inhibitors, and interleukin-6 inhibitors, whereas T-cell activation modulators did not affect them. Moreover, PD-1+CD38+CX3CR1+CD4+ T cells were identified as a treatment-resistant T cell subset that was characteristically increased in difficult-to-treat RA. CX3CR1+CD8+ T cells showed no significant difference between RA patients and healthy individuals, and no correlation with disease activity was observed. However, a correlation with age was observed in RA patients.

CONCLUSIONS

Our findings suggest that the immunopathogenesis of RA differs by age of onset, with CX3CR1+ age-associated cytotoxic CD4+ T cells playing a significant role in LORA. Additionally, the presence of a specific CX3CR1+ T cell subset may be linked to treatment resistance.

Cytotoxic Response of CD4+ T Cells Orchestrated by SLAMF4 in Rheumatoid Arthritis

OBJECTIVE

This study aimed to assess whether signaling lymphocytic activation molecule family receptors (SLAMFs) are involved in the shaping of the pathologic response of CD4+ T cells in rheumatoid arthritis (RA).

METHODS

Peripheral blood (PB) and synovial fluid (SF) mononuclear cells from patients with RA were freshly isolated. In RA, we used a multimodal approach to determine the involvement of numerous subpopulations of CD4+ T cells expressing SLAMFs. Experimentally, multiple flow cytometry panels, RNA sequencing, and stimulations were used. Analyses involved high-dimensional unsupervised clustering of flow cytometry data and pathway enrichment analyses of transcriptomic data.

RESULTS

In PB of patients with RA with active disease, SLAMF4+ effector memory CD4+ T cells (Tem) represented the only overrepresented subpopulation of CD4+ T cells expressing SLAMFs. This positive correlation between RA activity and SLAMF4+ Tem was restricted to those coexpressing the intracellular molecule SLAM-associated protein (SAP) and the tissue-homing receptor CCR5. Gene Set Enrichment Analysis of RNA sequencing data reveals that SLAMF4+ CCR5+ Tem display a cytotoxicity-related gene signature. Moreover, based on the differential expression of cytotoxicity markers (GPR56, CX3CR1, granzyme-B, perforin, and granulysin), unsupervised clustering of flow cytometry data identified distinct subpopulations of PB cytotoxic Tem. Among them, only SLAMF4high SAP+ CCR5+ Tem (Cytotox-F4high Tem) were correlated with RA activity. Remarkably, Cytotox-F4high Tem emerged as the only cytotoxic population of CD4+ T cells (CD4+ CTLs) present in SF of patients with active disease.

CONCLUSION

This study emphasizes that Cytotox-F4high Tem represent a significant CD4+ CTL subpopulation involved in RA, suggesting that their inhibition represent a promising therapeutic interest.

Oncolytic reprogramming of tumor microenvironment shapes CD4 T-cell memory via the IL6ra-Bcl6 axis for targeted control of glioblastoma

Oncolytic viruses (OVs) emerge as a promising cancer immunotherapy. However, the temporal impact on tumor cells and the tumor microenvironment, and the nature of anti-tumor immunity post-therapy remain largely unclear. Here we report that CD4+ T cells are required for durable tumor control in syngeneic murine models of glioblastoma multiforme after treatment with an oncolytic herpes simplex virus (oHSV) engineered to express IL-12. The upregulated MHCII on residual tumor cells facilitates programmed polyfunctional CD4+ T cells for tumor control and for recall responses. Mechanistically, the proper ratio of Bcl-6 to T-bet in CD4+ T cells navigates their enhanced anti-tumor capacity, and a reciprocal IL6ra-Bcl-6 regulatory axis in a memory CD4+ T-cell subset, which requires MHCII signals from reprogrammed tumor cells, tumor-infiltrating and resident myeloid cells, is necessary for the prolonged response. These findings uncover an OV-induced tumor/myeloid-CD4+ T-cell partnership, leading to long-term anti-tumor immune memory, and improved OV therapeutic efficacy.

Apheresis for the treatment of relapses in MS and NMOSD: reduced antibody reactivities, gene expression changes and potential clinical response indicators

Background

High-dose glucocorticoids are the standard treatment for acute relapses in patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD). Therapeutic apheresis can be considered for the escalation of relapse therapy, but some patients still do not recover sufficiently. We aimed to explore the effects of apheresis on humoral and cellular immune parameters and to identify features that correlate with beneficial clinical outcomes.

Methods

We studied two cohorts comprising a total of 63 patients with MS or NMOSD who were undergoing relapse therapy with either methylprednisolone or apheresis. Blood samples were collected immediately before and after therapy to isolate plasma or serum as well as immune cells. We then measured (1) concentrations of the immunoglobulin isotypes IgG, IgM and IgA, (2) antibody reactivities against 12 peptides derived from potential autoantigens and Epstein-Barr virus proteins, (3) frequencies of CD19+ B cells, CD3+ T cells and CD14+ monocytes, (4) transcriptome profiles of CD19+ B cells and CD4+ T cells and (5) mRNA levels of 7 cytotoxicity-related genes in CD4+ T cells. The data were compared with regard to changes under therapy and with regard to differences between clinical responders and non-responders.

Results

The initial therapy with methylprednisolone had no significant effect on immunoglobulin levels and (auto)antibody reactivities (n max=27 MS patients). In contrast, MS patients who underwent apheresis (n max=27) showed strong immunoglobulin reduction rates, especially for IgG, and decreased antibody reactivities against all tested peptides. EBNA1 (amino acids 391-410) was the only peptide that also reached the significance level in NMOSD patients (n=9). Non-responders to apheresis (n=12) had on average higher anti-EBNA1 (391-410) reactivities than responders (n=24) at baseline. Apheresis also led to a decrease in the proportion of monocytes, an increase in the proportion of T cells (n=29 patients with MS or NMOSD) and moderate transcriptome changes (n max=4 MS patients). A gene expression signature that is characteristic of CD4+ cytotoxic T lymphocytes (CD4-CTLs) was found to be elevated at baseline in non-responders to apheresis, although this could not be validated with statistical significance (n=19 MS patients).

Conclusion

Our data reveal that therapeutic apheresis in MS rapidly leads to a significant decrease in IgG reactivities against EBNA1 (391-410) and cross-reactive targets such as GlialCAM (370-389) and also has an impact on the gene expression of B cells and T cells. Further studies are required to verify whether anti-EBNA1 (391-410) antibody reactivities and the expression of CD4-CTL-related genes may be indicative of the individual clinical response to this therapy.

Expansion of peripheral cytotoxic CD4+ T cells in Alzheimer's disease: New insights from multi-omics evidence

The significance of the adaptive immune response in Alzheimer's disease (AD) is increasingly recognized. We analyzed scRNA-Seq data from AD patients, revealing a notable rise in CD4 cytotoxic T cells (CD4-CTLs) in peripheral blood mononuclear cells (PBMCs), validated in vivo and in vitro. This rise correlates with cognitive decline in AD patients. We also identified transcription factors TBX21 and MYBL1 as key drivers of CD4-CTL expansion. Further analyses indicate these cells are terminally differentiated, showing clonal expansion, metabolic changes, and unique communication patterns. Mendelian randomization identified risk genes SRGN and ITGB1, suggesting their genetic regulation in CD4-CTLs may contribute to AD. To summarize, our findings characterize the expansion of CD4-CTLs in the PBMCs of AD patients, providing valuable understanding into the possible mechanisms involved in the expansion of CD4-CTLs in AD.

Cancer-specific innate and adaptive immune rewiring drives resistance to PD-1 blockade in classic Hodgkin lymphoma

Hodgkin Reed-Sternberg (HRS) cells of classic Hodgkin lymphoma (cHL), like many solid tumors, elicit ineffective immune responses. However, patients with cHL are highly responsive to PD-1 blockade, which largely depends on HRS cell-specific retention of MHC class II and implicates CD4+ T cells and additional MHC class I-independent immune effectors. Here, we utilize single-cell RNA sequencing and spatial analysis to define shared circulating and microenvironmental features of the immune response to PD-1 blockade in cHL. Compared with non-responders, responding patients have more circulating CD4+ naïve and central memory T cells and B cells, as well as more diverse CD4+ T cell and B cell receptor repertoires. Importantly, a population of circulating and tumor-infiltrating IL1β+ monocytes/macrophages is detectable in patients with cHL but not healthy donors, and a proinflammatory, tumor-promoting signature of these circulating IL1β+ monocytes is associated with resistance to PD-1 blockade in cHL. Altogether, our findings reveal extensive immune rewiring and complementary roles of CD4+ T cells, B cells and IL1β+ monocytes in the response to PD-1 blockade and suggest that these features can be captured with a peripheral blood test.

Salivary Flow Rate in Patients with Sjögren's Syndrome: Correlations with Salivary Gland Ultrasound Findings and Biomarkers of Disease Activity

Sjögren's syndrome (SS) is a slowly progressive, chronic autoimmune inflammatory condition characterized by the affliction of the exocrine glands, with issues that derive from it markedly decreasing the quality of life of these patients. Salivary gland involvement can be identified through imaging methods. Among them, salivary gland ultrasonography (SGUS) is used as a diagnostic and prognostic tool in pSS. The aim of the present study was to assess the salivary flow rate and correlations between it and SGUS findings and markers of pSS activity. A total of 112 patients with pSS and 56 healthy subjects were included in this study. All patients underwent investigations including the measurement of serum autoantibodies, salivary flow rate determination, and ultrasonographic evaluation. SGUS modifications had a strong inverse correlation with salivary flow (r = -68.002, p < 0.0001) and a positive, strong correlation with IL-6 and Beta-2-microglobulin (r = -0.78 and r = -0.84, respectively, p < 0.001 in both cases). The SGUS findings were also strongly and positively correlated with the ESSDAI (r = -0.88, p < 0.0001) and Focus scores (r = -0.82, p < 0.0001). SGUS represents a non-invasive means of assessing the state of the salivary glands and, implicitly, the salivary flow of patients, offering valuable insights into disease progression and steps that can be taken in order to improve patients' quality of life.

Implications of accumulation of clonally expanded and senescent CD4+GNLY+ T cells in immunological non-responders of HIV-1 infection

Increased CD4+GNLY+ T cells have been confirmed to be inversely associated with CD4+ T cell count in immunological non-responders (INRs), however, the underlying mechanisms are unknown. This study aimed to elucidate the characteristics of CD4+GNLY+ T cells and their relationship with immune restoration. Single-cell RNA sequencing, single-cell TCR sequencing, and flow cytometry were used to analyze the frequency, phenotypes, and function of CD4+GNLY+ T cells. Moreover, Enzyme linked immunosorbent assay was performed to detect plasma cytokines production in patients. CD4+GNLY+ T cells were found to be highly clonally expanded, characterized by higher levels of cytotoxicity, senescence, P24, and HIV-1 DNA than CD4+GNLY- T cells. Additionally, the frequency of CD4+GNLY+ T cells increased after ART, and further increased in INRs, and were positively associated with the antiretroviral therapy duration in INR. Furthermore, increased IL-15 levels in INRs positively correlated with the frequency and senescence of CD4+GNLY+ T cells, suggesting that CD4+GNLY+ T cells may provide new insights for understanding the poor immune reconstitution of INRs. In conclusion, increased, highly clonally expanded, and senescent CD4+GNLY+ T cells may contribute to poor immune reconstitution in HIV-1 infection.

Chlorella vulgaris as a food substitute: Applications and benefits in the food industry

Chlorella vulgaris, a freshwater microalga, is gaining attention for its potential as a nutritious food source and dietary supplement. This review aims to provide a comprehensive discussion on C. vulgaris, evaluating its viability as a food substitute in the industry by exploring the nutritional value and application of C. vulgaris in the food industry. Rich in protein, lipids, carbohydrates, vitamins, and minerals, Chlorella offers substantial nutritional benefits, positioning it as a valuable food substitute. Its applications in the food industry include incorporation into smoothies, snacks, and supplements, enhancing the nutritional profile of various food products. The health benefits of Chlorella encompass antioxidant activity, immune system support, and detoxification, contributing to overall well-being. Despite these advantages, the commercialization of Chlorella faces significant challenges. These include variability in antibacterial activity due to strain and growth conditions, high production costs, contamination risks, and sensory issues such as unpleasant taste and smell. Additionally, Chlorella can accumulate heavy metals from its environment, necessitating stringent quality control measures. Future prospects involve improving Chlorella strains through genetic manipulation to enhance nutrient content, developing cost-effective culture systems, and exploring advanced processing techniques like pulsed electric fields for better digestibility. Addressing sensory issues through flavor-masking strategies and employing environmental management practices will further support Chlorella's integration into the food industry. Although C. vulgaris shows great potential as a nutritious food ingredient, overcoming existing challenges and optimizing production methods would be crucial for its successful adoption and widespread use.

SARS-CoV-2 infection elucidates features of pregnancy-specific immunity

Pregnancy is a risk factor for increased severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory infections, but the mechanisms underlying this risk are poorly understood. To gain insight into the role of pregnancy in modulating immune responses at baseline and upon SARS-CoV-2 infection, we collected peripheral blood mononuclear cells and plasma from 226 women, including 152 pregnant individuals and 74 non-pregnant women. We find that SARS-CoV-2 infection is associated with altered T cell responses in pregnant women, including a clonal expansion of CD4-expressing CD8+ T cells, diminished interferon responses, and profound suppression of monocyte function. We also identify shifts in cytokine and chemokine levels in the sera of pregnant individuals, including a robust increase of interleukin-27, known to drive T cell exhaustion. Our findings reveal nuanced pregnancy-associated immune responses, which may contribute to the increased susceptibility of pregnant individuals to viral respiratory infection.

Characterization of CD3+ T Lymphocytes in Human Coronary Thrombi with ST-segment Elevation Myocardial Infarction

BACKGROUND

 The occurrence and development of ST-segment elevation myocardial infarction (STEMI) are accompanied by coronary atherothrombosis and occlusion, and immune responses play prominent roles in their pathogeneses. However, the causes of atherothrombosis remain elusive, and a comprehensive study of T cell-mediated immune responses in coronary thrombi from STEMI patients is lacking.

OBJECTIVES

 The aim of this study was to determine the heterogeneity and clonality of CD3+ T lymphocytes in STEMI patients at the single-cell level.

METHODS

 Paired single-cell RNA and T cell receptor (TCR) sequencing was performed on CD3+ T lymphocytes in the coronary thrombi and peripheral blood of STEMI patients, as well as the blood from control subjects without coronary artery disease (CAD).

RESULTS

 Compared with those in the peripheral blood of STEMI patients, the activation, cytotoxicity, proinflammatory, and prothrombotic characteristics of CD3+ T lymphocytes in coronary thrombi were decreased, and the clonality of CD3+ T cells was increased. Compared with those from non-CAD controls, T lymphocytes from STEMI patients exhibited an upregulation of genes related to recent TCR engagement, suggesting antigen-specific stimulation in STEMI. Antigen specificity prediction using an algorithm indicated the probability of T cells from different patients binding to similar antigens for clonal expansion during STEMI.

CONCLUSION

 This study provides a basis for exploring the cellular heterogeneity of CD3+ T lymphocytes in the coronary thrombi and peripheral blood of STEMI patients. Identifying the precise adaptive immune mechanisms driving atherothrombosis may lead to innovative therapies that selectively target the aberrant immune response, resulting in more effective treatments for STEMI.

Lesional senescent CD4+ T cells mediate bystander cytolysis and contribute to the skin pathology of human cutaneous leishmaniasis

Cytotoxic activity is a hallmark of the immunopathogenesis in human cutaneous leishmaniasis (CL). In this study, we identified accumulation of CD4+ granzyme B producing T cells with increased cytotoxic capacity in CL lesions. These cells showed enhanced expression of activating NK receptors (NKG2D and NKG2C), diminished expression of inhibitory NKG2A, along with the upregulation of the senescence marker CD57. Notably, CD4+ T cells freshly isolated from CL lesions demonstrated remarkable capacity to mediate NL-like bystander cytolysis. Phenotypic analyses revealed that lesional CD4+ T cells are mainly composed of late-differentiated effector (CD27-CD45RA-) and terminally differentiated (senescent) TEMRA (CD27-CD45RA+) subsets. Interestingly, the TEMRA CD4+ T cells exhibited higher expression of granzyme B and CD107a. Collectively, our results provide the first evidence that senescent cytotoxic CD4+ T cells may support the skin pathology of human cutaneous leishmaniasis and, together with our previous findings, support the notion that multiple subsets of cytotoxic senescent cells may be involved in inducing the skin lesions in these patients.

State of the Field: Cytotoxic Immune Cell Responses in C. neoformans and C. deneoformans Infection

Cryptococcus neoformans is an environmental pathogen that causes life-threatening disease in immunocompromised persons. The majority of immunological studies have centered on CD4+ T-cell dysfunction and associated cytokine signaling pathways, optimization of phagocytic cell function against fungal cells, and identification of robust antigens for vaccine development. However, a growing body of literature exists regarding cytotoxic cells, specifically CD8+ T-cells, Natural Killer cells, gamma/delta T-cells, NK T-cells, and Cytotoxic CD4+ T-cells, and their role in the innate and adaptive immune response during C. neoformans and C. deneoformans infection. In this review, we (1) provide a comprehensive report of data gathered from mouse and human studies on cytotoxic cell function and phenotype, (2) discuss harmonious and conflicting results on cellular responses in mice models and human infection, (3) identify gaps of knowledge in the field ripe for exploration, and (4) highlight how innovative immunological tools could enhance the study of cytotoxic cells and their potential immunomodulation during cryptococcosis.

Sorting nexin 27-dependent regulation of Lck and CD4 tunes the initial stages of T-cell activation

Sorting nexin 27 is a unique member of the sorting nexin family of proteins that mediates the endosome-to-plasma membrane trafficking of cargos bearing a PSD95/Dlg1/ZO-1 (PDZ)-binding motif. In brain, sorting nexin 27 regulates synaptic plasticity, and its dysregulation contributes to cognitive impairment and neuronal degeneration. In T lymphocytes, sorting nexin 27 partners with diacylglycerol kinase ζ to facilitate polarized traffic and signaling at the immune synapse. By silencing sorting nexin 27 expression in a human T-cell line, we demonstrate that sorting nexin 27 is a key regulator of the early T-cell tyrosine-based signaling cascade. Sorting nexin 27 transcriptionally controls CD4 abundance in resting conditions and that of its associated molecule, Lck. This guarantees the adequate recruitment of Lck at the immune synapse, which is indispensable for subsequent activation of tyrosine phosphorylation-regulated events. In contrast, reduced sorting nexin 27 expression enhances NF-κB-dependent induction of CXCR4 and triggers production of lytic enzymes and proinflammatory cytokines. These results provide mechanistic explanation to previously described sorting nexin 27 function in the control of immune synapse organization and indicate that impaired sorting nexin 27 expression contributes to CD4 T-cell dysfunction.

Opportunities and challenges for T cell-based influenza vaccines

Vaccination remains our main defence against influenza, which causes substantial annual mortality and poses a serious pandemic threat. Influenza virus evades immunity by rapidly changing its surface antigens but, even when the vaccine is well matched to the current circulating virus strains, influenza vaccines are not as effective as many other vaccines. Influenza vaccine development has traditionally focused on the induction of protective antibodies, but there is mounting evidence that T cell responses are also protective against influenza. Thus, future vaccines designed to promote both broad T cell effector functions and antibodies may provide enhanced protection. As we discuss, such vaccines present several challenges that require new strategic and economic considerations. Vaccine-induced T cells relevant to protection may reside in the lungs or lymphoid tissues, requiring more invasive assays to assess the immunogenicity of vaccine candidates. T cell functions may contain and resolve infection rather than completely prevent infection and early illness, requiring vaccine effectiveness to be assessed based on the prevention of severe disease and death rather than symptomatic infection. It can be complex and costly to measure T cell responses and infrequent clinical outcomes, and thus innovations in clinical trial design are needed for economic reasons. Nevertheless, the goal of more effective influenza vaccines justifies renewed and intensive efforts.

Tissue-specific features of innate lymphoid cells in antiviral defense

Innate lymphocytes (ILCs) rapidly respond to and protect against invading pathogens and cancer. ILCs include natural killer (NK) cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer (LTi) cells and include type I, type II, and type III immune cells. While NK cells have been well recognized for their role in antiviral immunity, other ILC subtypes are emerging as players in antiviral defense. Each ILC subset has specialized functions that uniquely impact the antiviral immunity and health of the host depending on the tissue microenvironment. This review focuses on the specialized functions of each ILC subtype and their roles in antiviral immune responses across tissues. Several viruses within infection-prone tissues will be highlighted to provide an overview of the extent of the ILC immunity within tissues and emphasize common versus virus-specific responses.

West Nile virus triggers intestinal dysmotility via T cell-mediated enteric nervous system injury

Intestinal dysmotility syndromes have been epidemiologically associated with several antecedent bacterial and viral infections. To model this phenotype, we previously infected mice with the neurotropic flavivirus West Nile virus (WNV) and demonstrated intestinal transit defects. Here, we found that within 1 week of WNV infection, enteric neurons and glia became damaged, resulting in sustained reductions of neuronal cells and their networks of connecting fibers. Using cell-depleting antibodies, adoptive transfer experiments, and mice lacking specific immune cells or immune functions, we show that infiltrating WNV-specific CD4+ and CD8+ T cells damaged the enteric nervous system (ENS) and glia, which led to intestinal dysmotility; these T cells used multiple and redundant effector molecules including perforin and Fas ligand. In comparison, WNV-triggered ENS injury and intestinal dysmotility appeared to not require infiltrating monocytes, and damage may have been limited by resident muscularis macrophages. Overall, our experiments support a model in which antigen-specific T cell subsets and their effector molecules responding to WNV infection direct immune pathology against enteric neurons and supporting glia that results in intestinal dysmotility.

Cytotoxic CD4+ T Cells Are Induced during Infection with Chlamydia trachomatis

Chlamydia trachomatis is the most common cause of bacterial sexually transmitted infection in both men and women. Immunity to C. trachomatis involves many cell types, but CD4+ T cells play a key role in protecting the host during natural infection. Specifically, IFN-γ production by CD4+ T cells is the main effector responsible for bacterial clearance, yet the exact mechanism by which IFN-γ confers protection is poorly defined. In our efforts to define the specific mechanisms for bacterial clearance, we now show that IFN-γ upregulates expression of MHC class II (MHCII) on nonhematopoietic cells during C. trachomatis infection in vivo. We also find that MHCII expression on epithelial cells of the upper genital tract contributes to the efficient clearance of bacteria mediated by pathogen-specific CD4+ Th1 cells. As we further cataloged the protective mechanisms of C. trachomatis-specific CD4+ T cells, we found that the T cells also express granzyme B (GzmB) when coincubated with infected cells. In addition, during C. trachomatis infection of mice, primed activated-naive CD4+ Th1 cells displayed elevated granzyme transcripts (GzmA, GzmB, GzmM, GzmK, GzmC) compared with memory CD4+ T cells in vivo. Finally, using intracellular cytokine staining and a GzmB-/- mouse strain, we show that C. trachomatis-specific CD4+ Th1 cells express GzmB upon Ag stimulation, and that this correlates with Chlamydia clearance in vivo. Together these results have led us to conclude that Chlamydia-specific CD4+ Th1 cells develop cytotoxic capacity through engagement with nonhematopoietic MHCII, and this correlates to C. trachomatis clearance.

In-depth cross-validation of human and mouse CD4-specific minibodies for noninvasive PET imaging of CD4+ cells and response prediction to cancer immunotherapy

Increasing evidence emphasizes the pivotal role of CD4+ T cells in orchestrating cancer immunity. Noninvasive in vivo imaging of the temporal dynamics of CD4+ T cells and their distribution patterns might provide novel insights into their effector and regulator cell functions during cancer immunotherapy (CIT). Methods: We conducted a comparative analysis of 89Zr-labeled anti-mouse (m) and anti-human (h) CD4-targeting minibodies (Mbs) for in vivo positron emission tomography (PET)/magnetic resonance imaging (MRI) of CD4+ T cells in human xenografts, syngeneic tumor-bearing wild-type (WT), and human CD4+ knock-in (hCD4-KI) mouse models. Results: Both 89Zr-CD4-Mbs yielded high radiolabeling efficiencies of >90%, immunoreactivities of >70%, and specific in vitro binding to their target antigens. The specificity of in vivo targeting of 89Zr-hCD4-Mb was confirmed by PET/MRI, revealing ~4-fold greater 89Zr-hCD4-Mb uptake in subcutaneous hCD4+ hematopoietic peripheral blood acute lymphoblastic leukemia tumors (HPB-ALL) than in solid hCD4- diffuse histiocytic lymphomas (DHL) and 89Zr-mCD4-Mb uptake in hCD4+ HPB-ALL tumors. In a comparative cross-validation study in anti-programmed death ligand (αPD-L1)/anti-4-1BB-treated orthotopic PyMT mammary carcinoma-bearing hCD4-KI and WT mice, we detected 2- to 3-fold enhanced species-specific 89Zr-hCD4-Mb or 89Zr-mCD4-Mb uptake within CD4+ cell-enriched secondary lymphatic organs (lymph nodes and spleens). The 89Zr-hCD4-Mb uptake in the PyMT tumors was more pronounced in hCD4-KI mice compared to the WT control littermates. Most importantly, MC38 adenocarcinoma-bearing mice treated with a combination of αPD-L1 and anti-lymphocyte-activation gene 3 (αLag-3) antibodies exhibited ~1.4-fold higher 89Zr-mCD4-Mb uptake than mice that were not responsive to therapy or sham-treated mice. Conclusion: CD4 PET/MRI enabled monitoring of the CD4+ cell distribution in secondary lymphatic organs and the tumor microenvironment, capable of predicting sensitivity to CIT. Our imaging approach will provide deeper insights into the underlying molecular mechanisms of CD4-directed cancer immunotherapies in preclinical mouse models and is applicable for clinical translation.

Recurrent fever of unknown origin and unexplained bacteremia in a patient with a novel 4.5 Mb microdeletion in Xp11.23-p11.22

Fever of unknown origin (FUO) remains a formidable diagnostic challenge in the field of medicine. Numerous studies suggest an association between FUO and genetic factors, including chromosomal abnormalities. Here, we report a female patient with a 4.5 Mb Xp microdeletion, who presented with recurrent FUO, bacteremia, colitis, and hematochezia. To elucidate the underlying pathogenic mechanism, we employed a comprehensive approach involving single cell RNA sequencing, T cell receptor sequencing, and flow cytometry to evaluate CD4 T cells. Analysis of peripheral blood mononuclear cells revealed augmented Th1, Th2, and Th17 cell populations, and elevated levels of proinflammatory cytokines in serum. Notably, the patient exhibited impaired Treg cell function, possibly related to deletion of genes encoding FOPX3 and WAS. Single cell analysis revealed specific expansion of cytotoxic CD4 T lymphocytes, characterized by upregulation of various signature genes associated with cytotoxicity. Moreover, interferon-stimulated genes were upregulated in the CD4 T effector memory cluster. Further genetic analysis confirmed maternal inheritance of the Xp microdeletion. The patient and her mother exhibited X chromosome-skewed inactivation, a potential protective mechanism against extensive X chromosome deletions; however, the mother exhibited complete skewing and the patient exhibited incomplete skewing (85:15), which may have contributed to emergence of immunological symptoms. In summary, this case report describes an exceptional instance of FUO stemming from an incompletely inactivated X chromosome microdeletion, thereby increasing our understanding of the genetics underpinning FUO.

Lysine methylation modifications in tumor immunomodulation and immunotherapy: regulatory mechanisms and perspectives

Lysine methylation is a crucial post-translational modification (PTM) that significantly impacts gene expression regulation. This modification not only influences cancer development directly but also has significant implications for the immune system. Lysine methylation modulates immune cell functions and shapes the anti-tumor immune response, highlighting its dual role in both tumor progression and immune regulation. In this review, we provide a comprehensive overview of the intrinsic role of lysine methylation in the activation and function of immune cells, detailing how these modifications affect cellular processes and signaling pathways. We delve into the mechanisms by which lysine methylation contributes to tumor immune evasion, allowing cancer cells to escape immune surveillance and thrive. Furthermore, we discuss the therapeutic potential of targeting lysine methylation in cancer immunotherapy. Emerging strategies, such as immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell (CAR-T) therapy, are being explored for their efficacy in modulating lysine methylation to enhance anti-tumor immune responses. By targeting these modifications, we can potentially improve the effectiveness of existing treatments and develop novel therapeutic approaches to combat cancer more effectively.

Correction of age-associated defects in dendritic cells enables CD4+ T cells to eradicate tumors

Defective host defenses later in life are associated with changes in immune cell activities, suggesting that age-specific considerations are needed in immunotherapy approaches. In this study, we found that PD-1 and CTLA4-based cancer immunotherapies are unable to eradicate tumors in elderly mice. This defect in anti-tumor activity correlated with two known age-associated immune defects: diminished abundance of systemic naive CD8+ T cells and weak migratory activities of dendritic cells (DCs). We identified a vaccine adjuvant, referred to as a DC hyperactivator, which corrects DC migratory defects in the elderly. Vaccines containing tumor antigens and DC hyperactivators induced T helper type 1 (TH1) CD4+ T cells with cytolytic activity that drive anti-tumor immunity in elderly mice. When administered early in life, DC hyperactivators were the only adjuvant identified that elicited anti-tumor CD4+ T cells that persisted into old age. These results raise the possibility of correcting age-associated immune defects through DC manipulation.

Tumor immune microenvironment permissive to metastatic progression of ING4-deficient breast cancer

Deficiencies in the ING4 tumor suppressor are associated with advanced stage tumors and poor patient survival in cancer. ING4 was shown to inhibit NF-kB in several cancers. As NF-kB is a key mediator of immune response, the ING4/NF-kB axis is likely to manifest in tumor-immune modulation but has not been investigated. To characterize the tumor immune microenvironment associated with ING4-deficient tumors, three approaches were employed in this study: First, tissue microarrays composed of 246 primary breast tumors including 97 ING4-deficient tumors were evaluated for the presence of selective immune markers, CD68, CD4, CD8, and PD-1, using immunohistochemical staining. Second, an immune-competent mouse model of ING4-deficient breast cancer was devised utilizing CRISPR-mediated deletion of Ing4 in a Tp53 deletion-derived mammary tumor cell line; mammary tumors were evaluated for immune markers using flow cytometry. Lastly, the METABRIC gene expression dataset was evaluated for patient survival related to the immune markers associated with Ing4-deleted tumors. The results showed that CD68, CD4, CD8, or PD-1, was not significantly associated with ING4-deficient breast tumors, indicating no enrichment of macrophages, T cells, or exhausted T cell types. In mice, Ing4-deleted mammary tumors had a growth rate comparable to Ing4-intact tumors but showed increased tumor penetrance and metastasis. Immune marker analyses of Ing4-deleted tumors revealed a significant increase in tumor-associated macrophages (Gr-1loCD11b+F4/80+) and a decrease in granzyme B-positive (GzmB+) CD4+ T cells, indicating a suppressive and/or less tumoricidal immune microenvironment. The METABRIC data analyses showed that low expression of GZMB was significantly associated with poor patient survival, as was ING4-low expression, in the basal subtype of breast cancer. Patients with GZMB-low/ING4-low tumors had the worst survival outcomes (HR = 2.80, 95% CI 1.36-5.75, p = 0.0004), supportive of the idea that the GZMB-low immune environment contributes to ING4-deficient tumor progression. Collectively, the study results demonstrate that ING4-deficient tumors harbor a microenvironment that contributes to immune evasion and metastasis.

Deciphering CD4+ T cell-mediated responses against cancer

It's been long thought that CD8+ cytotoxic T cells play a major role in T cell-mediated antitumor responses, whereas CD4+ T cells merely provide some assistance to CD8+ T cells as the "helpers." In recent years, numerous studies support the notion that CD4+ T cells play an indispensable role in antitumor responses. Here, we summarize and discuss the current knowledge regarding the roles of CD4+ T cells in antitumor responses and immunotherapy, with a focus on the molecular and cellular mechanisms behind these observations. These new insights on CD4+ T cells may pave the way to further optimize cancer immunotherapy.

Dynamic Changes in the Immune Microenvironment in Tumor-Draining Lymph Nodes of a Lewis Lung Cancer Mouse Model After Microwave Ablation

PURPOSE

Microwave ablation (MWA) is a minimally invasive technique for treating lung cancer. It can induce immune response; however, its effect on the immune microenvironment in tumor-draining lymph nodes (TdLN) is not well understood. This study aims to identify changes in the immune microenvironment in TdLN following MWA in a Lewis lung cancer (LLC) mouse model.

METHODS

LLC mouse model was established and followed by MWA. TdLN were collected at various time points, including pre-MWA and days 1, 2, 4, and 8 post-MWA. Flow cytometry was used to determine the frequencies of CD4+ T cells, CD8+ T cells, regulatory T (Treg) cells, natural killer (NK) cells, dendritic cells (DCs) and other immune cells in the TdLN. Certain cytokines were also detected.

RESULTS

Compared with pre-MWA, the frequency of CD4+ T cells significantly increased from day 1 to day 8 post-MWA. The frequency of CD8+ T cells decreased significantly on days 2 and 4, but no significant changes occurred on days 1 and 8. Significant decreases in the frequencies of Treg cells and Klrg1+ Treg cells were observed from day 1 to day 4. On days 4 and 8, there was a significant increase in the frequency of NK cells. The frequency of resident cDC2 significantly increased on day 4, whereas CD11b+ migratory cDCs increased on day 1. Additionally, on day 4, a notable rise was observed in the frequency of NK cells secreting IFN-γ, while on day 8, there was a significant increase in the frequency of CD8+ T cells secreting both IFN-γ and TNF-α.

CONCLUSION

MWA of lung cancer can alter the immune microenvironment in the TdLN, triggering immune responses. These changes are particularly evident and intricate within the initial 4 days post-MWA. Treatment combined with MWA within a certain period may significantly enhance anti-tumor immunity.

TimiGP-Response: the pan-cancer immune landscape associated with response to immunotherapy

Accumulating evidence suggests that the tumor immune microenvironment (TIME) significantly influences the response to immunotherapy, yet this complex relationship remains elusive. To address this issue, we developed TimiGP-Response (TIME Illustration based on Gene Pairing designed for immunotherapy Response), a computational framework leveraging single-cell and bulk transcriptomic data, along with response information, to construct cell-cell interaction networks associated with responders and estimate the role of immune cells in treatment response. This framework was showcased in triple-negative breast cancer treated with immune checkpoint inhibitors targeting the PD-1:PD-L1 interaction, and orthogonally validated with imaging mass cytometry. As a result, we identified CD8+ GZMB+ T cells associated with responders and its interaction with regulatory T cells emerged as a potential feature for selecting patients who may benefit from these therapies. Subsequently, we analyzed 3,410 patients with seven cancer types (melanoma, non-small cell lung cancer, renal cell carcinoma, metastatic urothelial carcinoma, hepatocellular carcinoma, breast cancer, and esophageal cancer) treated with various immunotherapies and combination therapies, as well as several chemo- and targeted therapies as controls. Using TimiGP-Response, we depicted the pan-cancer immune landscape associated with immunotherapy response at different resolutions. At the TIME level, CD8 T cells and CD4 memory T cells were associated with responders, while anti-inflammatory (M2) macrophages and mast cells were linked to non-responders across most cancer types and datasets. Given that T cells are the primary targets of these immunotherapies and our TIME analysis highlights their importance in response to treatment, we portrayed the pan-caner landscape on 40 T cell subtypes. Notably, CD8+ and CD4+ GZMK+ effector memory T cells emerged as crucial across all cancer types and treatments, while IL-17-producing CD8+ T cells were top candidates associated with immunotherapy non-responders. In summary, this study provides a computational method to study the association between TIME and response across the pan-cancer immune landscape, offering resources and insights into immune cell interactions and their impact on treatment efficacy.

Neutrophil-mediated hypoxia drives pathogenic CD8+ T cell responses in cutaneous leishmaniasis

Cutaneous leishmaniasis caused by Leishmania parasites exhibits a wide range of clinical manifestations. Although parasites influence disease severity, cytolytic CD8+ T cell responses mediate disease. Although these responses originate in the lymph node, we found that expression of the cytolytic effector molecule granzyme B was restricted to lesional CD8+ T cells in Leishmania-infected mice, suggesting that local cues within inflamed skin induced cytolytic function. Expression of Blimp-1 (Prdm1), a transcription factor necessary for cytolytic CD8+ T cell differentiation, was driven by hypoxia within the inflamed skin. Hypoxia was further enhanced by the recruitment of neutrophils that consumed oxygen to produce ROS and ultimately increased the hypoxic state and granzyme B expression in CD8+ T cells. Importantly, lesions from patients with cutaneous leishmaniasis exhibited hypoxia transcription signatures that correlated with the presence of neutrophils. Thus, targeting hypoxia-driven signals that support local differentiation of cytolytic CD8+ T cells may improve the prognosis for patients with cutaneous leishmaniasis, as well as for other inflammatory skin diseases in which cytolytic CD8+ T cells contribute to pathogenesis.

Remodeling of T-cell mitochondrial metabolism to treat autoimmune diseases

T cells are key drivers of the pathogenesis of autoimmune diseases by producing cytokines, stimulating the generation of autoantibodies, and mediating tissue and cell damage. Distinct mitochondrial metabolic pathways govern the direction of T-cell differentiation and function and rely on specific nutrients and metabolic enzymes. Metabolic substrate uptake and mitochondrial metabolism form the foundational elements for T-cell activation, proliferation, differentiation, and effector function, contributing to the dynamic interplay between immunological signals and mitochondrial metabolism in coordinating adaptive immunity. Perturbations in substrate availability and enzyme activity may impair T-cell immunosuppressive function, fostering autoreactive responses and disrupting immune homeostasis, ultimately contributing to autoimmune disease pathogenesis. A growing body of studies has explored how metabolic processes regulate the function of diverse T-cell subsets in autoimmune diseases such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), autoimmune hepatitis (AIH), inflammatory bowel disease (IBD), and psoriasis. This review describes the coordination of T-cell biology by mitochondrial metabolism, including the electron transport chain (ETC), oxidative phosphorylation, amino acid metabolism, fatty acid metabolism, and one‑carbon metabolism. This study elucidated the intricate crosstalk between mitochondrial metabolic programs, signal transduction pathways, and transcription factors. This review summarizes potential therapeutic targets for T-cell mitochondrial metabolism and signaling in autoimmune diseases, providing insights for future studies.

Immune cell infiltration and inflammatory landscape in primary brain tumours

BACKGROUND

Primary malignant brain tumours are more than one-third of all brain tumours and despite the molecular investigation to identify cancer driver mutations, the current therapeutic options available are challenging due to high intratumour heterogeneity. In addition, an immunosuppressive and inflammatory tumour microenvironment strengthens cancer progression. Therefore, we defined an immune and inflammatory profiling of meningioma and glial tumours to elucidate the role of the immune infiltration in these cancer types.

METHODS

Using tissue microarrays of 158 brain tumour samples, we assessed CD3, CD4, CD8, CD20, CD138, Granzyme B (GzmB), 5-Lipoxygenase (5-LOX), Programmed Death-Ligand 1 (PD-L1), O-6-Methylguanine-DNA Methyltransferase (MGMT) and Transglutaminase 2 (TG2) expression by immunohistochemistry (IHC). IHC results were correlated using a Spearman correlation matrix. Transcript expression, correlation, and overall survival (OS) analyses were evaluated using public datasets available on GEPIA2 in Glioblastoma (GBM) and Lower Grade Glioma (LGG) cohorts.

RESULTS

Seven out of ten markers showed a significantly different IHC expression in at least one of the evaluated cohorts whereas CD3, CD4 and 5-LOX were differentially expressed between GBMs and astrocytomas. Correlation matrix analysis revealed that 5-LOX and GzmB expression were associated in both meningiomas and GBMs, whereas 5-LOX expression was significantly and positively correlated to TG2 in both meningioma and astrocytoma cohorts. These findings were confirmed with the correlation analysis of TCGA-GBM and LGG datasets. Profiling of mRNA levels indicated a significant increase in CD3 (CD3D, CD3E), and CD138 (SDC1) expression in GBM compared to control tissues. CD4 and 5-LOX (ALOX5) mRNA levels were significantly more expressed in tumour samples than in normal tissues in both GBM and LGG. In GBM cohort, GzmB (GZMB), SDC1 and MGMT gene expression predicted a poor overall survival (OS). Moreover, in LGG cohort, an increased expression of CD3 (CD3D, CD3E, CD3G), CD8 (CD8A), GZMB, CD20 (MS4A1), SDC1, PD-L1, ALOX5, and TG2 (TGM2) genes was associated with worse OS.

CONCLUSIONS

Our data have revealed that there is a positive and significant correlation between the expression of 5-LOX and GzmB, both at RNA and protein level. Further evaluation is needed to understand the interplay of 5-LOX and immune infiltration in glioma progression.

T-Cell-Based Platform for Functional Screening of T-Cell Receptors Identified in Single-Cell RNA Sequencing Data Sets of Tumor-Infiltrating T-Cells

The advent of single-cell RNA sequencing (scRNAseq) has enabled in-depth gene expression analysis of several thousand cells isolated from tissues. We recently reported the application of scRNAseq toward the dissection of the tumor-infiltrating T-cell repertoire in human pancreatic cancer samples. In this study, we demonstrated that combined whole transcriptome and T-cell receptor (TCR) sequencing provides an effective way to identify tumor-reactive TCR clonotypes on the basis of gene expression signatures. An important aspect in this respect was the experimental validation of TCR-mediated anti-tumor reactivity by means of an in vitro functional assay, which is the subject of the present protocol. This assay involves the transient transfection of mRNA gene constructs encoding TCRα/β pairs into a well-defined human T-cell line, followed by co-cultivation with the tumor cells of interest and detection of T-cell activation by flow cytometry. Due to the high transfectability and the low background reactivity of the mock-transfected T-cell line to a wide variety of tumor cells, this assay offers a highly robust and versatile platform for the functional screening of large numbers of TCR clonotypes as identified in scRNAseq data sets. Whereas the assay was initially developed to test TCRs of human origin, it was more recently also applied successfully for the screening of TCRs of murine origin. Key features • Efficient functional screening of-and discrimination between-TCRs isolated from tumor-reactive vs. bystander T-cell clones. • Applicable to TCRs from CD8+ and CD4+ tumor-infiltrating T-cells originating from patient-derived tumor samples and syngeneic mouse tumor models. • Rapid flow cytometric detection of T-cell activation by means of TNFα and CD107a expression after a 5 h T-cell/tumor cell co-cultivation.

Dual molecule targeting HDAC6 leads to intratumoral CD4+ cytotoxic lymphocytes recruitment through MHC-II upregulation on lung cancer cells

BACKGROUND

Despite the current therapeutic treatments including surgery, chemotherapy, radiotherapy and more recently immunotherapy, the mortality rate of lung cancer stays high. Regarding lung cancer, epigenetic modifications altering cell cycle, angiogenesis and programmed cancer cell death are therapeutic targets to combine with immunotherapy to improve treatment success. In a recent study, we uncovered that a molecule called QAPHA ((E)-3-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxyacrylamide) has a dual function as both a tubulin polymerization and HDAC inhibitors. Here, we investigate the impact of this novel dual inhibitor on the immune response to lung cancer.

METHODS

To elucidate the mechanism of action of QAPHA, we conducted a chemical proteomics analysis. Using an in vivo mouse model of lung cancer (TC-1 tumor cells), we assessed the effects of QAPHA on tumor regression. Tumor infiltrating immune cells were characterized by flow cytometry.

RESULTS

In this study, we first showed that QAPHA effectively inhibited histone deacetylase 6, leading to upregulation of HSP90, cytochrome C and caspases, as revealed by proteomic analysis. We confirmed that QAPHA induces immunogenic cell death (ICD) by expressing calreticulin at cell surface in vitro and demonstrated its efficacy as a vaccine in vivo. Remarkably, even at a low concentration (0.5 mg/kg), QAPHA achieved complete tumor regression in approximately 60% of mice treated intratumorally, establishing a long-lasting anticancer immune response. Additionally, QAPHA treatment promoted the infiltration of M1-polarized macrophages in treated mice, indicating the induction of a pro-inflammatory environment within the tumor. Very interestingly, our findings also revealed that QAPHA upregulated major histocompatibility complex class II (MHC-II) expression on TC-1 tumor cells both in vitro and in vivo, facilitating the recruitment of cytotoxic CD4+T cells (CD4+CTL) expressing CD4+, NKG2D+, CRTAM+, and Perforin+. Finally, we showed that tumor regression strongly correlates to MHC-II expression level on tumor cell and CD4+ CTL infiltrate.

CONCLUSION

Collectively, our findings shed light on the discovery of a new multitarget inhibitor able to induce ICD and MHC-II upregulation in TC-1 tumor cell. These two processes participate in enhancing a specific CD4+ cytotoxic T cell-mediated antitumor response in vivo in our model of lung cancer. This breakthrough suggests the potential of QAPHA as a promising agent for cancer treatment.

Cytotoxic Programming of CD4+ T Cells Is Regulated by Opposing Actions of the Related Transcription Factors Eos and Aiolos

In contrast to the "helper" activities of most CD4+ T effector subsets, CD4+ cytotoxic T lymphocytes (CD4-CTLs) perform functions normally associated with CD8+ T and NK cells. Specifically, CD4-CTLs secrete cytotoxic molecules and directly target and kill compromised cells in an MHC class II-restricted fashion. The functions of these cells have been described in diverse immunological contexts, including their ability to provide protection during antiviral and antitumor responses, as well as being implicated in autoimmunity. Despite their significance to human health, the complete mechanisms that govern their programming remain unclear. In this article, we identify the Ikaros zinc finger transcription factor Eos (Ikzf4) as a positive regulator of CD4-CTL differentiation during murine immune responses against influenza virus infection. We find that the frequency of Eos+ cells is elevated in lung CD4-CTL populations and that the cytotoxic gene program is compromised in Eos-deficient CD4+ T cells. Consequently, we observe a reduced frequency and number of lung-residing, influenza virus-responsive CD4-CTLs in the absence of Eos. Mechanistically, we determine that this is due, at least in part, to reduced expression of IL-2 and IL-15 cytokine receptor subunits on the surface of Eos-deficient CD4+ T cells, both of which support the CD4-CTL program. Finally, we find that Aiolos, a related Ikaros family member and known CD4-CTL antagonist, represses Eos expression by antagonizing STAT5-dependent activation of the Ikzf4 promoter. Collectively, our findings reveal a mechanism wherein Eos and Aiolos act in opposition to regulate cytotoxic programming of CD4+ T cells.

Age-associated CD4+ T cells with B cell-promoting functions are regulated by ZEB2 in autoimmunity

Aging is a significant risk factor for autoimmunity, and many autoimmune diseases tend to onset during adulthood. We conducted an extensive analysis of CD4+ T cell subsets from 354 patients with autoimmune disease and healthy controls via flow cytometry and bulk RNA sequencing. As a result, we identified a distinct CXCR3midCD4+ effector memory T cell subset that expands with age, which we designated "age-associated T helper (THA) cells." THA cells exhibited both a cytotoxic phenotype and B cell helper functions, and these features were regulated by the transcription factor ZEB2. Consistent with the highly skewed T cell receptor usage of THA cells, gene expression in THA cells from patients with systemic lupus erythematosus reflected disease activity and was affected by treatment with a calcineurin inhibitor. Moreover, analysis of single-cell RNA sequencing data revealed that THA cells infiltrate damaged organs in patients with autoimmune diseases. Together, our characterization of THA cells may facilitate improved understanding of the relationship between aging and autoimmune diseases.

Advancements in technology for characterizing the tumor immune microenvironment

Immunotherapy plays a key role in cancer treatment, however, responses are limited to a small number of patients. The biological basis for the success of immunotherapy is the complex interaction between tumor cells and tumor immune microenvironment (TIME). Historically, research on tumor immune constitution was limited to the analysis of one or two markers, more novel technologies are needed to interpret the complex interactions between tumor cells and TIME. In recent years, major advances have already been made in depicting TIME at a considerably elevated degree of throughput, dimensionality and resolution, allowing dozens of markers to be labeled simultaneously, and analyzing the heterogeneity of tumour-immune infiltrates in detail at the single cell level, depicting the spatial landscape of the entire microenvironment, as well as applying artificial intelligence (AI) to interpret a large amount of complex data from TIME. In this review, we summarized emerging technologies that have made contributions to the field of TIME, and provided prospects for future research.

CTLs heterogeneity and plasticity: implications for cancer immunotherapy

Cytotoxic T lymphocytes (CTLs) play critical antitumor roles, encompassing diverse subsets including CD4+, NK, and γδ T cells beyond conventional CD8+ CTLs. However, definitive CTLs biomarkers remain elusive, as cytotoxicity-molecule expression does not necessarily confer cytotoxic capacity. CTLs differentiation involves transcriptional regulation by factors such as T-bet and Blimp-1, although epigenetic regulation of CTLs is less clear. CTLs promote tumor killing through cytotoxic granules and death receptor pathways, but may also stimulate tumorigenesis in some contexts. Given that CTLs cytotoxicity varies across tumors, enhancing this function is critical. This review summarizes current knowledge on CTLs subsets, biomarkers, differentiation mechanisms, cancer-related functions, and strategies for improving cytotoxicity. Key outstanding questions include refining the CTLs definition, characterizing subtype diversity, elucidating differentiation and senescence pathways, delineating CTL-microbe relationships, and enabling multi-omics profiling. A more comprehensive understanding of CTLs biology will facilitate optimization of their immunotherapy applications. Overall, this review synthesizes the heterogeneity, regulation, functional roles, and enhancement strategies of CTLs in antitumor immunity, highlighting gaps in our knowledge of subtype diversity, definitive biomarkers, epigenetic control, microbial interactions, and multi-omics characterization. Addressing these questions will refine our understanding of CTLs immunology to better leverage cytotoxic functions against cancer.

Flublok Quadrivalent Vaccine Adjuvanted with R-DOTAP Elicits a Robust and Multifunctional CD4 T Cell Response That Is of Greater Magnitude and Functional Diversity Than Conventional Adjuvant Systems

It is clear that new approaches are needed to promote broadly protective immunity to viral pathogens, particularly those that are prone to mutation and escape from antibody-mediated immunity. CD4+ T cells, known to target many viral proteins and highly conserved peptide epitopes, can contribute greatly to protective immunity through multiple mechanisms. Despite this potential, CD4+ T cells are often poorly recruited by current vaccine strategies. Here, we have analyzed a promising new adjuvant (R-DOTAP), as well as conventional adjuvant systems AddaVax with or without an added TLR9 agonist CpG, to promote CD4+ T cell responses to the licensed vaccine Flublok containing H1, H3, and HA-B proteins. Our studies, using a preclinical mouse model of vaccination, revealed that the addition of R-DOTAP to Flublok dramatically enhances the magnitude and functionality of CD4+ T cells specific for HA-derived CD4+ T cell epitopes, far outperforming conventional adjuvant systems based on cytokine EliSpot assays and multiparameter flow cytometry. The elicited CD4+ T cells specific for HA-derived epitopes produce IL-2, IFN-γ, IL-4/5, and granzyme B and have multifunctional potential. Hence, R-DOTAP, which has been verified safe by human studies, can offer exciting opportunities as an immune stimulant for next-generation prophylactic recombinant protein-based vaccines.

Challenges in developing personalized neoantigen cancer vaccines

The recent success of cancer immunotherapies has highlighted the benefit of harnessing the immune system for cancer treatment. Vaccines have a long history of promoting immunity to pathogens and, consequently, vaccines targeting cancer neoantigens have been championed as a tool to direct and amplify immune responses against tumours while sparing healthy tissue. In recent years, extensive preclinical research and more than one hundred clinical trials have tested different strategies of neoantigen discovery and vaccine formulations. However, despite the enthusiasm for neoantigen vaccines, proof of unequivocal efficacy has remained beyond reach for the majority of clinical trials. In this Review, we focus on the key obstacles pertaining to vaccine design and tumour environment that remain to be overcome in order to unleash the true potential of neoantigen vaccines in cancer therapy.

Single-cell insights into immune dysregulation in rheumatoid arthritis flare versus drug-free remission

Immune-mediated inflammatory diseases (IMIDs) are typically characterised by relapsing and remitting flares of inflammation. However, the unpredictability of disease flares impedes their study. Addressing this critical knowledge gap, we use the experimental medicine approach of immunomodulatory drug withdrawal in rheumatoid arthritis (RA) remission to synchronise flare processes allowing detailed characterisation. Exploratory mass cytometry analyses reveal three circulating cellular subsets heralding the onset of arthritis flare - CD45RO+PD1hi CD4+ and CD8+ T cells, and CD27+CD86+CD21- B cells - further characterised by single-cell sequencing. Distinct lymphocyte subsets including cytotoxic and exhausted CD4+ memory T cells, memory CD8+CXCR5+ T cells, and IGHA1+ plasma cells are primed for activation in flare patients. Regulatory memory CD4+ T cells (Treg cells) increase at flare onset, but with dysfunctional regulatory marker expression compared to drug-free remission. Significant clonal expansion is observed in T cells, but not B cells, after drug cessation; this is widespread throughout memory CD8+ T cell subsets but limited to the granzyme-expressing cytotoxic subset within CD4+ memory T cells. Based on our observations, we suggest a model of immune dysregulation for understanding RA flare, with potential for further translational research towards novel avenues for its treatment and prevention.