Integrative single-cell analysis of LUAD: elucidating immune cell dynamics and prognostic modeling based on exhausted CD8+ T cells.

Background: The tumor microenvironment (TME) plays a pivotal role in the progression and metastasis of lung adenocarcinoma (LUAD). However, the detailed characteristics of LUAD and its associated microenvironment are yet to be extensively explored. This study aims to delineate a comprehensive profile of the immune cells within the LUAD microenvironment, including CD8+ T cells, CD4+ T cells, and myeloid cells. Subsequently, based on marker genes of exhausted CD8+ T cells, we aim to establish a prognostic model for LUAD. Method: Utilizing the Seurat and Scanpy packages, we successfully constructed an immune microenvironment atlas for LUAD. The Monocle3 and PAGA algorithms were employed for pseudotime analysis, pySCENIC for transcription factor analysis, and CellChat for analyzing intercellular communication. Following this, a prognostic model for LUAD was developed, based on the marker genes of exhausted CD8+ T cells, enabling effective risk stratification in LUAD patients. Our study included a thorough analysis to identify differences in TME, mutation landscape, and enrichment across varying risk groups. Moreover, by integrating risk scores with clinical features, we developed a new nomogram. The expression of model genes was validated via RT-PCR, and a series of cellular experiments were conducted, elucidating the potential oncogenic mechanisms of GALNT2. Results: Our study developed a single-cell atlas for LUAD from scRNA-seq data of 19 patients, examining crucial immune cells in LUAD's microenvironment. We underscored pDCs' role in antigen processing and established a Cox regression model based on CD8_Tex-LAYN genes for risk assessment. Additionally, we contrasted prognosis and tumor environments across risk groups, constructed a new nomogram integrating clinical features, validated the expression of model genes via RT-PCR, and confirmed GALNT2's function in LUAD through cellular experiments, thereby enhancing our understanding and approach to LUAD treatment. Conclusion: The creation of a LUAD single-cell atlas in our study offered new insights into its tumor microenvironment and immune cell interactions, highlighting the importance of key genes associated with exhausted CD8+ T cells. These discoveries have enabled the development of an effective prognostic model for LUAD and identified GALNT2 as a potential therapeutic target, significantly contributing to the improvement of LUAD diagnosis and treatment strategies.

Advancements in Stimulus-Responsive Co-Delivery Nanocarriers for Enhanced Cancer Immunotherapy.

Cancer immunotherapy has emerged as a novel therapeutic approach against tumors, with immune checkpoint inhibitors (ICIs) making significant clinical practice. The traditional ICIs, PD-1 and PD-L1, augment the cytotoxic function of T cells through the inhibition of tumor immune evasion pathways, ultimately leading to the initiation of an antitumor immune response. However, the clinical implementation of ICIs encounters obstacles stemming from the existence of an immunosuppressive tumor microenvironment and inadequate infiltration of CD8+T cells. Considerable attention has been directed towards advancing immunogenic cell death (ICD) as a potential solution to counteract tumor cell infiltration and the immunosuppressive tumor microenvironment. This approach holds promise in transforming "cold" tumors into "hot" tumors that exhibit responsiveness to antitumor. By combining ICD with ICIs, a synergistic immune response against tumors can be achieved. However, the combination of ICD inducers and PD-1/PD-L1 inhibitors is hindered by issues such as poor targeting and uncontrolled drug release. An advantageous solution presented by stimulus-responsive nanocarrier is integrating the physicochemical properties of ICD inducers and PD-1/PD-L1 inhibitors, facilitating precise delivery to specific tissues for optimal combination therapy. Moreover, these nanocarriers leverage the distinct features of the tumor microenvironment to accomplish controlled drug release and regulate the kinetics of drug delivery. This article aims to investigate the advancement of stimulus-responsive co-delivery nanocarriers utilizing ICD and PD-1/PD-L1 inhibitors. Special focus is dedicated to exploring the advantages and recent advancements of this system in enabling the combination of ICIs and ICD inducers. The molecular mechanisms of ICD and ICIs are concisely summarized. In conclusion, we examine the potential research prospects and challenges that could greatly enhance immunotherapeutic approaches for cancer treatment.

TOB1 modulates neutrophil phenotypes to influence gastric cancer progression and immunotherapy efficacy.

Introduction: The ErbB-2.1(TOB1) signaling transducer protein is a tumor-suppressive protein that actively suppresses the malignant phenotype of gastric cancer cells. Yet, TOB1 negatively regulates the activation and growth of different immune cells. Understanding the expression and role of TOB1 in the gastric cancer immune environment is crucial to maximize its potential in targeted immunotherapy. Methods: This study employed multiplex immunofluorescence analysis to precisely delineate and quantify the expression of TOB1 in immune cells within gastric cancer tissue microarrays. Univariate and multivariate Cox analyses were performed to assess the influence of clinical-pathological parameters, immune cells, TOB1, and double-positive cells on the prognosis of gastric cancer patients. Subsequent experiments included co-culture assays of si-TOB1-transfected neutrophils with AGS or HGC-27 cells, along with EdU, invasion, migration assays, and bioinformatics analyses, aimed at elucidating the mechanisms through which TOB1 in neutrophils impacts the prognosis of gastric cancer patients. Results: We remarkably revealed that TOB1 exhibits varying expression levels in both the nucleus (nTOB1) and cytoplasm (cTOB1) of diverse immune cell populations, including CD8+ T cells, CD66b+ neutrophils, FOXP3+ Tregs, CD20+ B cells, CD4+ T cells, and CD68+ macrophages within gastric cancer and paracancerous tissues. Significantly, TOB1 was notably concentrated in CD66b+ neutrophils. Survival analysis showed that a higher density of cTOB1/nTOB1+CD66b+ neutrophils was linked to a better prognosis. Subsequent experiments revealed that, following stimulation with the supernatant of tumor tissue culture, the levels of TOB1 protein and mRNA in neutrophils decreased, accompanied by enhanced apoptosis. HL-60 cells were successfully induced to neutrophil-like cells by DMSO. Neutrophils-like cells with attenuated TOB1 gene expression by si-TOB1 demonstrated heightened apoptosis, consequently fostering a malignant phenotype in AGS and HCG-27 cells upon co-cultivation. The subsequent analysis of the datasets from TCGA and TIMER2 revealed that patients with high levels of TOB1 combined neutrophils showed better immunotherapy response. Discussion: This study significantly advances our comprehension of TOB1's role within the immune microenvironment of gastric cancer, offering promising therapeutic targets for immunotherapy in this context.

Exercise accelerates recruitment of CD8+ T cell to promotes anti-tumor immunity in lung cancer via epinephrine.

BACKGROUND AND PURPOSE: In recent years, there has been extensive research on the role of exercise as an adjunctive therapy for cancer. However, the potential mechanisms underlying the anti-tumor therapy of exercise in lung cancer remain to be fully elucidated. As such, our study aims to confirm whether exercise-induced elevation of epinephrine can accelerate CD8+ T cell recruitment through modulation of chemokines and thus ultimately inhibit tumor progression. METHOD: C57BL/6 mice were subcutaneously inoculated with Lewis lung cancer cells (LLCs) to establish a subcutaneous tumor model. The tumor mice were randomly divided into different groups to performed a moderate-intensity exercise program on a treadmill for 5 consecutive days a week, 45 min a day. The blood samples and tumor tissues were collected after exercise for IHC, RT-qPCR, ELISA and Western blot. In addition, another group of mice received daily epinephrine treatment for two weeks (0.05 mg/mL, 200 µL i.p.) (EPI, n = 8) to replicate the effects of exercise on tumors in vivo. Lewis lung cancer cells were treated with different concentrations of epinephrine (0, 5, 10, 20 µM) to detect the effect of epinephrine on chemokine levels via ELISA and RT-qPCR. RESULTS: This study reveals that both pre- and post-cancer exercise effectively impede the tumor progression. Exercise led to an increase in EPI levels and the infiltration of CD8+ T cell into the lung tumor. Exercise-induced elevation of EPI is involved in the regulation of Ccl5 and Cxcl10 levels further leading to enhanced CD8+ T cell infiltration and ultimately inhibiting tumor progression. CONCLUSION: Exercise training enhance the anti-tumor immunity of lung cancer individuals. These findings will provide valuable insights for the future application of exercise therapy in clinical practice.

Experimental trials of predicted CD4+ and CD8+ T-cell epitopes of respiratory syncytial virus.

Background: Respiratory syncytial virus (RSV) is the most common cause of viral lower respiratory tract infections (LRTIs) in young children around the world and an important cause of LRTI in the elderly. The available treatments and FDA-approved vaccines for RSV only lessen the severity of the infection and are recommended for infants and elderly people. Methods: We focused on developing a broad-spectrum vaccine that activates the immune system to directly combat RSV. The objective of this study is to identify CD4+ and CD8+ T-cell epitopes using an immunoinformatics approach to develop RSV vaccines. The efficacy of these peptides was validated through in-vitro and in-vivo studies involving healthy and diseased animal models. Results: For each major histocompatibility complex (MHC) class-I and II, we found three epitopes of RSV proteins including F, G, and SH with an antigenic score of >0.5 and a projected SVM score of <5. Experimental validation of these peptides on female BALB/c mice was conducted before and after infection with the RSV A2 line 19f. We found that the 3RVMHCI (CD8+) epitope of the F protein showed significant results of white blood cells (19.72 × 103 cells/µl), neutrophils (6.01 × 103 cells/µl), lymphocytes (12.98 × 103 cells/µl), IgG antibodies (36.9 µg/ml), IFN-γ (86.96 ng/L), and granzyme B (691.35 pg/ml) compared to control at the second booster dose of 10 µg. Similarly, 4RVMHCII (CD4+) of the F protein substantially induced white blood cells (27.08 × 103 cells/µl), neutrophils (6.58 × 103 cells/µl), lymphocytes (16.64 × 103 cells/µl), IgG antibodies (46.13 µg/ml), IFN-γ (96.45 ng/L), and granzyme B (675.09 pg/ml). In-vitro studies showed that 4RVMHCII produced a significant level of antibodies in sera on day 45 comparable to mice infected with the virus. 4RVMHCII also induced high IFN-γ and IL-2 secretions on the fourth day of the challenge compared to the preinfectional stage. Conclusion: In conclusion, epitopes of the F protein showed considerable immune response and are suitable for further validation.

TLR5 agonist in combination with anti-PD-1 treatment enhances anti-tumor effect through M1/M2 macrophage polarization shift and CD8+ T cell priming.

Immune checkpoint inhibitors have revolutionized anti-tumor therapy, notably improving treatment responses in various tumors. However, many patients remain non-responsive and do not experience benefits. Given that Toll-like receptors (TLRs) can counteract tumor immune tolerance by stimulating both innate and adaptive immune responses, TLR agonists are being explored as potential immune adjuvants for cancer treatment. In this study, we assessed the potential of enhancing the efficacy of immune checkpoint inhibitors by activating innate immunity with a TLR5 agonist. In a mouse tumor model, combination therapy with TLR5 agonist and anti-PD-1 significantly inhibited tumor growth. The TLR5 agonist shifted the balance from M2-like to M1-like macrophages and upregulated the expression of co-stimulatory molecules in macrophages. Furthermore, TLR5 agonist promoted the activation and tumor infiltration of CD8+ T cells. As a result, the TLR5 agonist augmented the anti-tumor efficacy of anti-PD-1, suggesting its potential in modulating the tumor microenvironment to enhance the anti-tumor response. Our findings point toward the possibility of optimizing immune checkpoint inhibitor therapy using TLR5 agonists.

Enhanced Therapeutic Potential of Hybrid Exosomes Loaded with Paclitaxel for Cancer Therapy.

The advancement of exosome studies has positioned engineered exosomes as crucial biomaterials for the development of advanced drug delivery systems. This study focuses on developing a hybrid exosome system by fusing mesenchymal stem cells (MSCs) exosomes with folate-targeted liposomes. The aim was to improve the drug loading capacity and target modification of exosome nanocarriers for delivering the first-line chemotherapy drug paclitaxel (PTX) and its effectiveness was assessed through cellular uptake studies to evaluate its ability to deliver drugs to tumor cells in vitro. Additionally, in vivo experiments were conducted using a CT26 tumor-bearing mouse model to assess the therapeutic efficacy of hybrid exosomes loaded with PTX (ELP). Cellular uptake studies demonstrated that ELP exhibited superior drug delivery capabilities to tumor cells in vitro. Moreover, in vivo experiments revealed that ELP significantly suppressed tumor growth in the CT26 tumor-bearing mouse model. Notably, for the first time, we examined the tumor microenvironment following intratumoral administration of ELP. We observed that ELP treatment activated CD4+ and CD8+ T cells, reduced the expression of M2 type tumor-associated macrophages (TAMs), polarized TAMs towards the M1 type, and decreased regulatory T cells (Tregs). Our research highlights the considerable therapeutic efficacy of ELP and its promising potential for future application in cancer therapy. The development of hybrid exosomes presents an innovative approach to enhance drug delivery and modulate the tumor microenvironment, offering exciting prospects for effective cancer treatment strategies.

Thermo-immune synergy: Camrelizumab plus microwave ablation in preoperative early-stage breast cancer.

Immunotherapy has enhanced breast cancer outcomes, but optimizing combination therapies is crucial. Integrating additional treatment modalities, like physical therapies, holds promise for optimizing efficacy. Pan et al. recently reported that combining preoperative immunotherapy with microwave ablation is safe and feasible in early-stage breast cancer, effectively sensitizing peripheral CD8+ T cells.1.

Autologous human preclinical modeling of melanoma interpatient clinical responses to immunotherapeutics.

BACKGROUND: Despite recent advances in immunotherapy, a substantial population of late-stage melanoma patients still fail to achieve sustained clinical benefit. Lack of translational preclinical models continues to be a major challenge in the field of immunotherapy; thus, more optimized translational models could strongly influence clinical trial development. To address this unmet need, we designed a preclinical model reflecting the heterogeneity in melanoma patients' clinical responses that can be used to evaluate novel immunotherapies and synergistic combinatorial treatment strategies. Using our all-autologous humanized melanoma mouse model, we examined the efficacy of a novel engineered interleukin 2 (IL-2)-based cytokine variant immunotherapy. METHODS: To study immune responses and antitumor efficacy for human melanoma tumors, we developed an all-autologous humanized melanoma mouse model using clinically annotated, matched patient tumor cells and peripheral blood mononuclear cells (PBMCs). After inoculating immunodeficient NSG mice with patient tumors and an adoptive cell transfer of autologous PBMCs, mice were treated with anti-PD-1, a novel investigational engineered IL-2-based cytokine (nemvaleukin), or recombinant human IL-2 (rhIL-2). The pharmacodynamic effects and antitumor efficacy of these treatments were then evaluated. We used tumor cells and autologous PBMCs from patients with varying immunotherapy responses to both model the diversity of immunotherapy efficacy observed in the clinical setting and to recapitulate the heterogeneous nature of melanoma. RESULTS: Our model exhibited long-term survival of engrafted human PBMCs without developing graft-versus-host disease. Administration of an anti-PD-1 or nemvaleukin elicited antitumor responses in our model that were patient-specific and were found to parallel clinical responsiveness to checkpoint inhibitors. An evaluation of nemvaleukin-treated mice demonstrated increased tumor-infiltrating CD4+ and CD8+ T cells, preferential expansion of non-regulatory T cell subsets in the spleen, and significant delays in tumor growth compared with vehicle-treated controls or mice treated with rhIL-2. CONCLUSIONS: Our model reproduces differential effects of immunotherapy in melanoma patients, capturing the inherent heterogeneity in clinical responses. Taken together, these data demonstrate our model's translatability for novel immunotherapies in melanoma patients. The data are also supportive for the continued clinical investigation of nemvaleukin as a novel immunotherapeutic for the treatment of melanoma.

Unlocking PD-1 antibody resistance: The MUC1 DNA vaccine augments CD8+ T cell infiltration and attenuates tumour suppression.

In light of increasing resistance to PD1 antibody therapy among certain patient populations, there is a critical need for in-depth research. Our study assesses the synergistic effects of a MUC1 DNA vaccine and PD1 antibody for surmounting PD1 resistance, employing a murine CT26/MUC1 colon carcinoma model for this purpose. When given as a standalone treatment, PD1 antibodies showed no impact on tumour growth. Additionally, there was no change observed in the intra-tumoural T-cell ratios or in the functionality of T-cells. In contrast, the sole administration of a MUC1 DNA vaccine markedly boosted the cytotoxicity of CD8+ T cells by elevating IFN-γ and granzyme B production. Our compelling evidence highlights that combination therapy more effectively inhibited tumour growth and prolonged survival compared to either monotherapy, thus mitigating the limitations intrinsic to single-agent therapies. This enhanced efficacy was driven by a significant alteration in the tumour microenvironment, skewing it towards pro-immunogenic conditions. This assertion is backed by a raised CD8+/CD4+ T-cell ratio and a decrease in immunosuppressive MDSC and Treg cell populations. On the mechanistic front, the synergistic therapy amplified expression levels of CXCL13 in tumours, subsequently facilitating T-cell ingress into the tumour setting. In summary, our findings advocate for integrated therapy as a potent mechanism for surmounting PD1 antibody resistance, capitalizing on improved T-cell functionality and infiltration. This investigation affords critical perspectives on enhancing anti-tumour immunity through the application of innovative therapeutic strategies.

High frequencies of alpha common cold coronavirus/SARS-CoV-2 cross-reactive functional CD4+ and CD8+ memory T cells are associated with protection from symptomatic and fatal SARS-CoV-2 infections in unvaccinated COVID-19 patients.

Background: Cross-reactive SARS-CoV-2-specific memory CD4+ and CD8+ T cells are present in up to 50% of unexposed, pre-pandemic, healthy individuals (UPPHIs). However, the characteristics of cross-reactive memory CD4+ and CD8+ T cells associated with subsequent protection of asymptomatic coronavirus disease 2019 (COVID-19) patients (i.e., unvaccinated individuals who never develop any COVID-19 symptoms despite being infected with SARS-CoV-2) remains to be fully elucidated. Methods: This study compares the antigen specificity, frequency, phenotype, and function of cross-reactive memory CD4+ and CD8+ T cells between common cold coronaviruses (CCCs) and SARS-CoV-2. T-cell responses against genome-wide conserved epitopes were studied early in the disease course in a cohort of 147 unvaccinated COVID-19 patients who were divided into six groups based on the severity of their symptoms. Results: Compared to severely ill COVID-19 patients and patients with fatal COVID-19 outcomes, the asymptomatic COVID-19 patients displayed significantly: (i) higher rates of co-infection with the 229E alpha species of CCCs (α-CCC-229E); (ii) higher frequencies of cross-reactive functional CD134+CD137+CD4+ and CD134+CD137+CD8+ T cells that cross-recognized conserved epitopes from α-CCCs and SARS-CoV-2 structural, non-structural, and accessory proteins; and (iii) lower frequencies of CCCs/SARS-CoV-2 cross-reactive exhausted PD-1+TIM3+TIGIT+CTLA4+CD4+ and PD-1+TIM3+TIGIT+CTLA4+CD8+ T cells, detected both ex vivo and in vitro. Conclusions: These findings (i) support a crucial role of functional, poly-antigenic α-CCCs/SARS-CoV-2 cross-reactive memory CD4+ and CD8+ T cells, induced following previous CCCs seasonal exposures, in protection against subsequent severe COVID-19 disease and (ii) provide critical insights into developing broadly protective, multi-antigen, CD4+, and CD8+ T-cell-based, universal pan-Coronavirus vaccines capable of conferring cross-species protection.

Probiotic lactic acid bacteria promote anti-tumor immunity through enhanced major histocompatibility complex class I-restricted antigen presentation machinery in dendritic cells.

Lactic acid bacteria (LAB) possess the ability to argument T cell activity through functional modification of antigen presenting cells (APCs), such as dendritic cells (DCs) and macrophages. Nevertheless, the precise mechanism underlying LAB-induced enhancement of antigen presentation in APCs remains incompletely understood. To address this question, we investigated the detailed mechanism underlying the enhancement of major histocompatibility complex (MHC) class I-restricted antigen presentation in DCs using a probiotic strain known as Lactococcus lactis subsp. Cremoris C60. We found that Heat-killed-C60 (HK-C60) facilitated the processing and presentation of ovalbumin (OVA) peptide antigen OVA257-264 (SIINFEKL) via H-2Kb in bone marrow-derived dendritic cells (BMDCs), leading to increased generation of effector CD8+ T cells both in vitro and in vivo. We also revealed that HK-C60 stimulation augmented the activity of 20S immunoproteasome (20SI) in BMDCs, thereby enhancing the MHC class I-restricted antigen presentation machinery. Furthermore, we assessed the impact of HK-C60 on CD8+ T cell activation in an OVA-expressing B16-F10 murine melanoma model. Oral administration of HK-C60 significantly attenuated tumor growth compared to control treatment. Enhanced Ag processing and presentation machineries in DCs from both Peyer's Patches (PPs) and lymph nodes (LNs) resulted in an increased tumor antigen specific CD8+ T cells. These findings shed new light on the role of LAB in MHC class-I restricted antigen presentation and activation of CD8+ T cells through functional modification of DCs.

The expression of CTLA-4 in hepatic alveolar echinococcosis patients and blocking CTLA-4 to reverse T cell exhaustion in Echinococcus multilocularis-infected mice.

Alveolar echinococcosis (AE) is a zoonotic parasitic disease caused by the infection of Echinococcus multilocularis (E. multilocularis) larvae. Cytotoxic T-lymphocyte antigen 4 (CTLA-4) produces inhibitory signals and induces T cell exhaustion, thereby inhibiting the parasiticidal efficacy of the liver immune system. Therefore, the purpose of this study is to explore how T-cell exhaustion contributes to AE and whether blocking CTLA-4 could reverse T cell exhaustion. Here we discovered that the expression of CTLA-4 was increased in the infiltrating margin around the lesion of the liver from AE patients by using western blot and immunohistochemistry assay. Multiple fluorescence immunohistochemistry identified that CTLA-4 and CD4/CD8 molecules were co-localized. For in vitro experiments, it was found that the sustained stimulation of E. multilocularis antigen could induce T cell exhaustion, blocking CTLA-4-reversed T cell exhaustion. For in vivo experiments, the expression of CTLA-4 was increased in the liver of E. multilocularis-infected mice, and the CTLA-4 and CD4/CD8 molecules were co-localized. Flow cytometry analysis demonstrated that the percentages of both CD4+ T cells and CD8+ T cells in the liver and peripheral blood were significantly increased and induced T exhaustion. When the mice were treated with anti-CTLA-4 antibodies, the number and weight of the lesions decreased significantly. Meanwhile, the flow cytometry results suggested that blocking CTLA-4 could effectively reverse T cell exhaustion and reactivate immune function. Our work reveals that blocking CTLA-4 could effectively reverse the T cell exhaustion caused by E. multilocularis and could be used as a novel target for the treatment of AE.

Exploratory mass cytometry analysis reveals immunophenotypes of cancer treatment-related pneumonitis.

Anticancer treatments can result in various adverse effects, including infections due to immune suppression/dysregulation and drug-induced toxicity in the lung. One of the major opportunistic infections is Pneumocystis jirovecii pneumonia (PCP), which can cause severe respiratory complications and high mortality rates. Cytotoxic drugs and immune-checkpoint inhibitors (ICIs) can induce interstitial lung diseases (ILDs). Nonetheless, the differentiation of these diseases can be difficult, and the pathogenic mechanisms of such diseases are not yet fully understood. To better comprehend the immunophenotypes, we conducted an exploratory mass cytometry analysis of immune cell subsets in bronchoalveolar lavage fluid from patients with PCP, cytotoxic drug-induced ILD (DI-ILD), and ICI-associated ILD (ICI-ILD) using two panels containing 64 markers. In PCP, we observed an expansion of the CD16+ T cell population, with the highest CD16+ T proportion in a fatal case. In ICI-ILD, we found an increase in CD57+ CD8+ T cells expressing immune checkpoints (TIGIT+ LAG3+ TIM-3+ PD-1+), FCRL5+ B cells, and CCR2+ CCR5+ CD14+ monocytes. These findings uncover the diverse immunophenotypes and possible pathomechanisms of cancer treatment-related pneumonitis.

Simultaneous analysis of pMHC binding and reactivity unveils virus-specific CD8 T cell immunity to a concise epitope set.

CD8 T cells provide immunity to virus infection through recognition of epitopes presented by peptide major histocompatibility complexes (pMHCs). To establish a concise panel of widely recognized T cell epitopes from common viruses, we combined analysis of TCR down-regulation upon stimulation with epitope-specific enumeration based on barcode-labeled pMHC multimers. We assess CD8 T cell binding and reactivity for 929 previously reported epitopes in the context of 1 of 25 HLA alleles representing 29 viruses. The prevalence and magnitude of CD8 T cell responses were evaluated in 48 donors and reported along with 137 frequently recognized virus epitopes, many of which were underrepresented in the public domain. Eighty-four percent of epitope-specific CD8 T cell populations demonstrated reactivity to peptide stimulation, which was associated with effector and long-term memory phenotypes. Conversely, nonreactive T cell populations were associated primarily with naive phenotypes. Our analysis provides a reference map of epitopes for characterizing CD8 T cell responses toward common human virus infections.

Delay induced stability switch in a mathematical model of CD8 T-cell response to SARS-CoV-2 mediated by receptor ACE2.

The pathogen SARS-CoV-2 binds to the receptor angiotensin-converting enzyme 2 (ACE2) of the target cells and then replicates itself through the host, eventually releasing free virus particles. After infection, the CD8 T-cell response is triggered and appears to play a critical role in the defense against virus infections. Infected cells and their activated CD8 T-cells can cause tissue damage. Here, we established a mathematical model of within-host SARS-CoV-2 infection that incorporates the receptor ACE2, the CD8 T-cell response, and the damaged tissues. According to this model, we can get the basic reproduction number R0 and the immune reproduction number R1. We provide the theoretical proof for the stability of the disease-free equilibrium, immune-inactivated equilibrium, and immune-activated equilibrium. Finally, our numerical simulations show that the time delay in CD8 T-cell production can induce complex dynamics such as stability switching. These results provide insights into the mechanisms of SARS-CoV-2 infection and may help in the development of effective drugs against COVID-19.

Biomimetic MDSCs membrane coated black phosphorus nanosheets system for photothermal therapy/photodynamic therapy synergized chemotherapy of cancer.

Photothermal therapy is favored by cancer researchers due to its advantages such as controllable initiation, direct killing and immune promotion. However, the low enrichment efficiency of photosensitizer in tumor site and the limited effect of single use limits the further development of photothermal therapy. Herein, a photo-responsive multifunctional nanosystem was designed for cancer therapy, in which myeloid-derived suppressor cell (MDSC) membrane vesicle encapsulated decitabine-loaded black phosphorous (BP) nanosheets (BP@ Decitabine @MDSCs, named BDM). The BDM demonstrated excellent biosafety and biochemical characteristics, providing a suitable microenvironment for cancer cell killing. First, the BDM achieves the ability to be highly enriched at tumor sites by inheriting the ability of MDSCs to actively target tumor microenvironment. And then, BP nanosheets achieves hyperthermia and induces mitochondrial damage by its photothermal and photodynamic properties, which enhancing anti-tumor immunity mediated by immunogenic cell death (ICD). Meanwhile, intra-tumoral release of decitabine induced G2/M cell cycle arrest, further promoting tumor cell apoptosis. In vivo, the BMD showed significant inhibition of tumor growth with down-regulation of PCNA expression and increased expression of high mobility group B1 (HMGB1), calreticulin (CRT) and caspase 3. Flow cytometry revealed significantly decreased infiltration of MDSCs and M2-macrophages along with an increased proportion of CD4+, CD8+ T cells as well as CD103+ DCs, suggesting a potentiated anti-tumor immune response. In summary, BDM realizes photothermal therapy/photodynamic therapy synergized chemotherapy for cancer.

PREX2 contributes to radiation resistance by inhibiting radiotherapy-induced tumor immunogenicity via cGAS/STING/IFNs pathway in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) lacks established biomarkers or molecular targets for predicting or enhancing radiation response. Phosphatidylinositol-3,4,5-triphosphate-dependent Rac exchange factor 2 (PREX2) exhibits intricate implications in tumorigenesis and progression. Nevertheless, the precise role and underlying mechanisms of PREX2 in CRC radioresistance remain unclear. METHODS: RNA-seq was employed to identify differentially expressed genes between radioresistant CRC cell lines and their parental counterparts. PREX2 expression was scrutinized using Western blotting, real-time PCR, and immunohistochemistry. The radioresistant role of PREX2 was assessed through in vitro colony formation assay, apoptosis assay, comet assay, and in vivo xenograft tumor models. The mechanism of PREX2 was elucidated using RNA-seq and Western blotting. Finally, a PREX2 small-molecule inhibitor, designated PREX-in1, was utilized to enhance the efficacy of ionizing radiation (IR) therapy in CRC mouse models. RESULTS: PREX2 emerged as the most significantly upregulated gene in radioresistant CRC cells. It augmented the radioresistant capacity of CRC cells and demonstrated potential as a marker for predicting radioresistance efficacy. Mechanistically, PREX2 facilitated DNA repair by upregulating DNA-PKcs, suppressing radiation-induced immunogenic cell death, and impeding CD8+ T cell infiltration through the cGAS/STING/IFNs pathway. In vivo, the blockade of PREX2 heightened the efficacy of IR therapy. CONCLUSIONS: PREX2 assumes a pivotal role in CRC radiation resistance by inhibiting the cGAS/STING/IFNs pathway, presenting itself as a potential radioresistant biomarker and therapeutic target for effectively overcoming radioresistance in CRC.

Soluble CD27 is an intrathecal biomarker of T-cell-mediated lesion activity in multiple sclerosis.

OBJECTIVE: Soluble CD27 is a promising cerebrospinal fluid inflammatory biomarker in multiple sclerosis. In this study, we investigate relevant immune and neuro-pathological features of soluble CD27 in multiple sclerosis. METHODS: Protein levels of soluble CD27 were correlated to inflammatory cell subpopulations and inflammatory cytokines and chemokines detected in cerebrospinal fluid of 137 patients with multiple sclerosis and 47 patients with inflammatory and non-inflammatory neurological disease from three independent cohorts. Production of soluble CD27 was investigated in cell cultures of activated T and B cells and CD27-knockout T cells. In a study including matched cerebrospinal fluid and post-mortem brain tissues of patients with multiple sclerosis and control cases, levels of soluble CD27 were correlated with perivascular and meningeal infiltrates and with neuropathological features. RESULTS: We demonstrate that soluble CD27 favours the differentiation of interferon-γ-producing T cells and is released through a secretory mechanism activated by TCR engagement and regulated by neutral sphingomyelinase. We also show that the levels of soluble CD27 correlate with the representation of inflammatory T cell subsets in the CSF of patients with relapsing-remitting multiple sclerosis and with the magnitude of perivascular and meningeal CD27 + CD4 + and CD8 + T cell infiltrates in post-mortem central nervous system tissue, defining a subgroup of patients with extensive active inflammatory lesions. INTERPRETATION: Our results demonstrate that soluble CD27 is a biomarker of disease activity, potentially informative for personalized treatment and monitoring of treatment outcomes.

Extracellular vesicle-mediated communication between CD8+ cytotoxic T cells and tumor cells.

Tumors pose a significant global public health challenge, resulting in numerous fatalities annually. CD8+ T cells play a crucial role in combating tumors; however, their effectiveness is compromised by the tumor itself and the tumor microenvironment (TME), resulting in reduced efficacy of immunotherapy. In this dynamic interplay, extracellular vesicles (EVs) have emerged as pivotal mediators, facilitating direct and indirect communication between tumors and CD8+ T cells. In this article, we provide an overview of how tumor-derived EVs directly regulate CD8+ T cell function by carrying bioactive molecules they carry internally and on their surface. Simultaneously, these EVs modulate the TME, indirectly influencing the efficiency of CD8+ T cell responses. Furthermore, EVs derived from CD8+ T cells exhibit a dual role: they promote tumor immune evasion while also enhancing antitumor activity. Finally, we briefly discuss current prevailing approaches that utilize functionalized EVs based on tumor-targeted therapy and tumor immunotherapy. These approaches aim to present novel perspectives for EV-based tumor treatment strategies, demonstrating potential for advancements in the field.