Transcriptome profiles of organ tissues from pigs experimentally infected with African swine fever virus in early phase of infection

African swine fever, caused by African swine fever virus (ASFV), is a highly contagious and fatal disease that poses a significant threat to the global pig industry. The limited information on ASFV pathogenesis and ASFV-host interactions has recently prompted numerous transcriptomic studies. However, most of these studies have focused on elucidating the transcriptome profiles of ASFV-infected porcine alveolar macrophages in vitro. Here, we analyzed dynamic transcriptional patterns in vivo in nine organ tissues (spleen, submandibular lymph node, mesenteric lymph node, inguinal lymph node, tonsils, lungs, liver, kidneys, and heart) obtained from pigs in the early stages of ASFV infection (1 and 3 d after viremia). We observed rapid spread of ASFV to the spleen after viremia, followed by broad transmission to the liver and lungs and subsequently, the submandibular and inguinal lymph nodes. Profound variations in gene expression patterns were observed across all organs and at all time-points, providing an understanding of the distinct defence strategies employed by each organ against ASFV infection. All ASFV-infected organs exhibited a collaborative response, activating immune-associated genes such as S100A8, thereby triggering a pro-inflammatory cytokine storm and interferon activation. Functional analysis suggested that ASFV exploits the PI3K-Akt signalling pathway to evade the host immune system. Overall, our findings provide leads into the mechanisms underlying pathogenesis and host immune responses in different organs during the early stages of infection, which can guide further explorations, aid the development of efficacious antiviral strategies against ASFV, and identify valuable candidate gene targets for vaccine development.

Chemokine receptor PET imaging: Bridging molecular insights with clinical applications

Chemokine receptors are important components of cellular signaling and play a critical role in directing leukocytes during inflammatory reactions. Their importance extends to numerous pathological processes, including tumor differentiation, angiogenesis, metastasis, and associations with multiple inflammatory disorders. The necessity to monitor the in vivo interactions of cellular chemokine receptors has been driven the recent development of novel positron emission tomography (PET) imaging agents. This imaging modality provides non-invasive localization and quantitation of these receptors that cannot be provided through blood or tissue-based assays. Herein, we provide a review of PET imaging of the chemokine receptors that have been imaged to date, namely CXCR3, CXCR4, CCR2, CCR5, and CMKLR1. The quantification of these receptors can aid in understanding various diseases, including cancer, atherosclerosis, idiopathic pulmonary fibrosis, and acute respiratory distress syndrome. The development of specific radiotracers targeting these receptors will be discussed, including promising results for disease diagnosis and management. However, challenges persist in fully translating these imaging advancements into practical therapeutic applications. Given the success of CXCR4 PET imaging to date, future research should focus on clinical translation of these approaches to understand their role in the management of a wide variety of diseases.

Central nervous system immune-related disorders after SARS-CoV-2 vaccination: a multicenter study

Background

COVID-19 vaccines have been approved due to their excellent safety and efficacy data and their use has also permitted to reduce neurological complications of SARS-CoV-2. However, clinical trials were underpowered to detect rare adverse events. Herein, the aim was to characterize the clinical spectrum and immunological features of central nervous system (CNS) immune-related events following SARS-CoV-2 vaccination.

Methods

Multicenter, retrospective, cohort study (December 1, 2020-April 30, 2022). Inclusion criteria were (1) de novo CNS disorders developing after SARS-CoV-2 vaccination (probable causal relationship as per 2021 Butler criteria) (2); evidence for an immune-mediated etiology, as per (i) 2016 Graus criteria for autoimmune encephalitis (AE); (ii) 2015 Wingerchuk criteria for neuromyelitis optica spectrum disorders; (iii) criteria for myelitis.

Results

Nineteen patients were included from 7 tertiary referral hospitals across Italy and France (one of them being a national referral center for AE), over almost 1 year and half of vaccination campaign. Vaccines administered were mRNA-based (63%) and adenovirus-vectored (37%). The median time between vaccination and symptoms onset was 14 days (range: 2-41 days). CSF was inflammatory in 74%; autoantibodies were detected in 5%. CSF cytokine analysis (n=3) revealed increased CXCL-10 (IP-10), suggesting robust T-cell activation. The patients had AE (58%), myelitis (21%), acute disseminated encephalomyelitis (ADEM) (16%), and brainstem encephalitis (5%). All patients but 2 received immunomodulatory treatment. At last follow-up (median 130 days; range: 32-540), only one patient (5%) had a mRS>2.

Conclusion

CNS adverse events of COVID-19 vaccination appear to be very rare even at reference centers and consist mostly of antibody-negative AE, myelitis, and ADEM developing approximately 2 weeks after vaccination. Most patients improve following immunomodulatory treatment.

Posttranscriptional Events Orchestrate Immune Homeostasis of CD8+ T Cells

Maintaining immune homeostasis is instrumental for host health. Immune cells, such as T cells, are instrumental for the eradication of pathogenic bacteria, fungi and viruses. Furthermore, T cells also play a major role in the fight against cancer. Through the formation of immunological memory, a pool of antigen-experienced T cells remains in the body to rapidly protect the host upon reinfection or retransformation. In order to perform their protective function, T cells produce cytolytic molecules, such as granzymes and perforin, and cytokines such as interferon γ and tumor necrosis factor α. Recently, it has become evident that posttranscriptional regulatory events dictate the kinetics and magnitude of cytokine production by murine and human CD8+ T cells. Here, the recent literature regarding the role posttranscriptional regulation plays in maintaining immune homeostasis of antigen-experienced CD8+ T cells is reviewed.

SLC7A11, a potential immunotherapeutic target in lung adenocarcinoma

SLC7A11 has significant translational value in cancer treatment. However, there are few studies on whether SLC7A11 affects the immune status of lung adenocarcinoma (LUAD). Information on SLC7A11 expression and its impact on prognosis was obtained from the cancer genome atlas and gene expression omnibus databases. The differentially expressed genes (DEGs) were analysed by GO and KEGG. GSEA enrichment analysis was performed in the SLC7A11-high and SLC7A11-low groups. The relationship between SLC7A11 and tumour immunity, immune checkpoints, and immune cell infiltration was studied using R language. We analysed the correlation between SLC7A11 and chemotactic factors (CFs) and chemokine receptors using the TISIDB database. SLC7A11 is overexpressed in many tumours, including LUAD. The 5-year overall survival of patients in the SLC7A11-high group was lower than in the SLC7A11-low group. KEGG analysis found that the DEGs were enriched in ferroptosis signaling pathways. GSEA analysis found that the survival-related signaling pathways were enriched in the SLC7A11-low group. The SLC7A11-low group had higher immune scores and immune checkpoint expression. SLC7A11 was negatively correlated with many immune cells (CD8+ T cells, immature dendritic cells), CFs, chemokine receptors (such as CCL17/19/22/23, CXCL9/10/11/14, CCR4/6, CX3CR1, CXCR3) and MHCs (major histocompatibility complex). SLC7A11 may regulate tumour immunity and could be a potential therapeutic target for LUAD.

Monocytes and T cells incorporated in full skin equivalents to study innate or adaptive immune reactions after burn injury

Introduction

Thermal injury often leads to prolonged and excessive inflammation, which hinders the recovery of patients. There is a notable absence of suitable animal-free models for investigating the inflammatory processes following burn injuries, thereby impeding the development of more effective therapies to improve burn wound healing in patients.

Methods

In this study, we established a human full skin equivalent (FSE) burn wound model and incorporated human peripheral blood-derived monocytes and T cells.

Results

Upon infiltration into the FSEs, the monocytes differentiated into macrophages within a span of 7 days. Burn-injured FSEs exhibited macrophages with increased expression of HLA-DR+ and elevated production of IL-8 (CXCL8), in comparison to uninjured FSEs. Among the T cells that actively migrated into the FSEs, the majority were CD4+ and CD25+. These T cells demonstrated augmented expression of markers associated with regulatory T cell, Th1, or Th17 activity, which coincided with significant heightened cytokine production, including IFN-γ, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IP-10 (CXCL10), and TGF-β1. Burn injury did not impact the studied effector T cell subsets or cytokine levels.

Discussion

Collectively, this study represents a significant advancement in the development of an immunocompetent human skin model, specifically tailored for investigating burn-induced innate or adaptive immune reactions at the site of burn injury.

Versatile Tissue-Injectable Hydrogels with Extended Hydrolytic Release of Bioactive Protein Therapeutics

Hydrogels generally have broad utilization in healthcare due to their tunable structures, high water content, and inherent biocompatibility. FDA-approved applications of hydrogels include spinal cord regeneration, skin fillers, and local therapeutic delivery. Drawbacks exist in the clinical hydrogel space, largely pertaining to inconsistent therapeutic exposure, short-lived release windows, and difficulties inserting the polymer into tissue. In this study, we engineered injectable, biocompatible hydrogels that function as a local protein therapeutic depot with a high degree of user-customizability. We showcase a PEG-based hydrogel functionalized with bioorthogonal strain-promoted azide-alkyne cycloaddition (SPAAC) handles for its polymerization and functionalization with a variety of payloads. Small-molecule and protein cargos, including chemokines and antibodies, were site-specifically modified with hydrolysable "azidoesters" of varying hydrophobicity via direct chemical conjugation or sortase-mediated transpeptidation. These hydrolysable esters afforded extended release of payloads linked to our hydrogels beyond diffusion; with timescales spanning days to months dependent on ester hydrophobicity. Injected hydrogels polymerize in situ and remain in tissue over extended periods of time. Hydrogel-delivered protein payloads elicit biological activity after being modified with SPAAC-compatible linkers, as demonstrated by the successful recruitment of murine T-cells to a mouse melanoma model by hydrolytically released murine CXCL10. These results highlight a highly versatile, customizable hydrogel-based delivery system for local delivery of protein therapeutics with payload release profiles appropriate for a variety of clinical needs.

CXCL9 inhibition does not ameliorate disease in murine models of both primary and secondary hemophagocytic lymphohistiocytosis

Hemophagocytic Lymphohistiocytosis (HLH) is a group of disorders culminating in systemic inflammation and multi-organ failure with high incidence of hepatic dysfunction. Overproduction of IFN-γ is the main immunopathological driver in this disorder. Monokine induced by IFN-γ (CXCL9) serves as a biomarker for disease activity and response to treatment in this disorder. However, very little is understood about the actual functional role of CXCL9 in pathogenesis in HLH. In the current study, we sought to determine the role of CXCL9 in pathogenesis in murine models of both Familial HLH (prf1^-/-) and Toll Like Receptor (TLR) 9 repeated stimulation induced Macrophage Activation Syndrome (MAS), a form of secondary HLH. FHL and MAS were induced in both CXCL9 genetically deficient mice (cxcl9^-/-) and controls as well as using AMG487, a pharmacological antagonist of the CXCL9 receptor, CXCR3. Results showed that CXCL9 genetic deficiency did not improve disease parameters or hepatitis in both models. Consistent with genetic ablation of CXCL9, inhibition of its receptor, CXCR3, by AMG487 did not show any significant effects in the FHL model. Taken together, inhibition of CXCL9-CXCR3 interaction does not ameliorate HLH physiology in general, or hepatitis as a classical target organ of disease.

Organized B cell sites in cartilaginous fishes reveal the evolutionary foundation of germinal centers

The absence of germinal centers (GCs) in cartilaginous fishes lies at odds with data showing that nurse sharks can produce robust antigen-specific responses and affinity mature their B cell repertoires. To investigate this apparent incongruity, we performed RNA sequencing on single nuclei, allowing us to characterize the cell types present in the nurse shark spleen, and RNAscope to provide in situ cellular resolution of key marker gene expression following immunization with R-phycoerythrin (PE). We tracked PE to the splenic follicles where it co-localizes with CXCR5high centrocyte-like B cells and a population of putative T follicular helper (Tfh) cells, surrounded by a peripheral ring of Ki67+ AID+ CXCR4+ centroblast-like B cells. Further, we reveal selection of mutations in B cell clones dissected from these follicles. We propose that the B cell sites identified here represent the evolutionary foundation of GCs, dating back to the jawed vertebrate ancestor.

EGFR-selective activation of CD27 co-stimulatory signaling by a bispecific antibody enhances anti-tumor activity of T cells

A higher density of tumor infiltrating lymphocytes (TILs) in the tumor microenvironment, particularly cytotoxic CD8+ T cells, is associated with improved clinical outcome in various cancers. However, local inhibitory factors can suppress T cell activity and hinder anti-tumor immunity. Notably, TILs from various cancer types express the co-stimulatory Tumor Necrosis Factor receptor CD27, making it a potential target for co-stimulation and re-activation of tumor-infiltrated and tumor-reactive T cells. Anti-cancer therapeutics based on exploiting CD27-mediated T cell co-stimulation have proven safe, but clinical responses remain limited. This is likely because current monoclonal antibodies fail to effectively activate CD27 signaling, as this receptor requires higher-order receptor cross-linking. Here, we report on a bispecific antibody, CD27xEGFR, that targets both CD27 and the tumor antigen, epidermal growth factor receptor (EGFR). By targeting EGFR, which is commonly expressed on carcinomas, CD27xEGFR induced cancer cell-localized crosslinking and activation of CD27. The design of CD27xEGFR includes an Fc-silent domain, which is designed to minimize potential toxicity by reducing Fc gamma receptor-mediated binding and activation of immune cells. CD27xEGFR bound to both of its targets simultaneously and triggered EGFR-restricted co-stimulation of T cells as measured by T cell proliferation, T cell activation markers, cytotoxicity and IFN-γ release. Further, CD27xEGFR augmented T cell cytotoxicity in a panel of artificial antigen-presenting carcinoma cell line models, leading to Effector-to-Target ratio-dependent elimination of cancer cells. Taken together, we present the in vitro characterization of a novel bispecific antibody that re-activates T cell immunity in EGFR-expressing cancers through targeted co-stimulation of CD27.

Pellino Proteins in Viral Immunity and Pathogenesis

Pellino proteins are a family of evolutionarily conserved ubiquitin ligases involved in intracellular signaling in a wide range of cell types. They are essential for microbe detection and the initiation of innate and adaptive immune responses. Some viruses specifically target the Pellino proteins as part of their immune evasion strategies. Through studies of mouse models of viral infections in the central nervous system, heart, lungs, and skin, the Pellino proteins have been linked to both beneficial and detrimental immune responses. Only in recent years have some of the involved mechanisms been identified. The objective of this review is to highlight the many diverse aspects of viral immunity and pathogenesis that the Pellino proteins have been associated with, in order to promote further research into their functions. After a brief introduction to the cellular signaling mechanisms involving Pellino proteins, their physiological roles in the initiation of immune responses, pathogenesis through excess inflammation, immune regulation, and cell death are presented. Known viral immune evasion strategies are also described. Throughout, areas that require more in-depth investigation are identified. Future research into the functions of the Pellino protein family may reveal fundamental insights into how our immune system works. Such knowledge may be leveraged in the fight against viral infections and their sequala.

Gene expression of peripheral blood mononuclear cells and CD8+ T cells from gilts after PRRSV infection

Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-stranded RNA virus, which emerged in Europe and U.S.A. in the late 1980s and has since caused huge economic losses. Infection with PRRSV causes mild to severe respiratory and reproductive clinical symptoms in pigs. Alteration of the host immune response by PRRSV is associated with the increased susceptibility to secondary viral and bacterial infections resulting in more serious and chronic disease. However, the expression profiles underlying innate and adaptive immune responses to PRRSV infection are yet to be further elucidated. In this study, we investigated gene expression profiles of PBMCs and CD8⁺ T cells after PRRSV AUT15-33 infection. We identified the highest number of differentially expressed genes in PBMCs and CD8⁺ T cells at 7 dpi and 21 dpi, respectively. The gene expression profile of PBMCs from infected animals was dominated by a strong innate immune response at 7 dpi which persisted through 14 dpi and 21 dpi and was accompanied by involvement of adaptive immunity. The gene expression pattern of CD8⁺ T cells showed a strong adaptive immune response to PRRSV, leading to the formation of highly differentiated CD8⁺ T cells starting from 14 dpi. The hallmark of the CD8⁺ T-cell response was the increased expression of effector and cytolytic genes (PRF1, GZMA, GZMB, GZMK, KLRK1, KLRD1, FASL, NKG7), with the highest levels observed at 21 dpi. Temporal clustering analysis of DEGs of PBMCs and CD8⁺ T cells from PRRSV-infected animals revealed three and four clusters, respectively, suggesting tight transcriptional regulation of both the innate and the adaptive immune response to PRRSV. The main cluster of PBMCs was related to the innate immune response to PRRSV, while the main clusters of CD8⁺ T cells represented the initial transformation and differentiation of these cells in response to the PRRSV infection. Together, we provided extensive transcriptomics data explaining gene signatures of the immune response of PBMCs and CD8⁺ T cells after PRRSV infection. Additionally, our study provides potential biomarker targets useful for vaccine and therapeutics development.

Altered T cell infiltration and enrichment of leukocyte regulating pathways within aged skeletal muscle are associated impaired muscle function following influenza infection

Older adults have diminished immune responses that increase susceptibility to infectious diseases, such as influenza (flu). In older adults, flu infection can lead to hospitalization, catastrophic disability, and mortality. We previously demonstrated severe and prolonged muscle degradation and atrophy in aged mice during flu infection. Here, we utilized an unbiased transcriptomic analysis to elucidate mechanisms of flu-induced muscular declines in a mouse model. Our results showed age-related gene expression differences including downregulation of genes associated with muscle regeneration and organization and upregulation of genes associated with pro-inflammatory cytokines and migratory immune pathways in aged mice when compared to young. Pathway analysis revealed significant enrichment of leukocyte migration and T cell activation pathways in the aged muscle during infection. Intramuscular CD4 T cells increased in both young and aged mice during infection, while intramuscular CD8 T cells increased exclusively in aged muscle. CD4 T cells in young muscle were regulatory T cells (Treg), while those in aged were T follicular helper (Tfh) and Th2 cells. Correspondingly, IL-33, an important cytokine for Treg accumulation within tissue, increased only in young flu-infected muscle. Conversely, CXCL10 (IP-10) increased only in aged muscle suggesting a continued recruitment of CD8 T cells into the aged muscle during flu infection. Overall, our findings elucidate a link between flu-induced disability and dysregulated intracellular T cell recruitment into flu-injured muscle with aging. Furthermore, we uncovered potential pathways involved that can be targeted to develop preventative and therapeutic interventions to avert disability and maintain independence following infection.

IL-2 is inactivated by the acidic pH environment of tumors enabling engineering of a pH-selective mutein

Cytokines interact with their receptors in the extracellular space to control immune responses. How the physicochemical properties of the extracellular space influence cytokine signaling is incompletely elucidated. Here, we show that the activity of interleukin-2 (IL-2), a cytokine critical to T cell immunity, is profoundly affected by pH, limiting IL-2 signaling within the acidic environment of tumors. Generation of lactic acid by tumors limits STAT5 activation, effector differentiation, and antitumor immunity by CD8+ T cells and renders high-dose IL-2 therapy poorly effective. Directed evolution enabled selection of a pH-selective IL-2 mutein (Switch-2). Switch-2 binds the IL-2 receptor subunit IL-2Rα with higher affinity, triggers STAT5 activation, and drives CD8+ T cell effector function more potently at acidic pH than at neutral pH. Consequently, high-dose Switch-2 therapy induces potent immune activation and tumor rejection with reduced on-target toxicity in normal tissues. Last, we show that sensitivity to pH is a generalizable property of a diverse range of cytokines with broad relevance to immunity and immunotherapy in healthy and diseased tissues.

Integrated machine learning methods identify FNDC3B as a potential prognostic biomarker and correlated with immune infiltrates in glioma

Background

Recent discoveries have revealed that fibronectin type III domain containing 3B (FNDC3B) acts as an oncogene in various cancers; however, its role in glioma remains unclear.

Methods

In this study, we comprehensively investigated the expression, prognostic value, and immune significance of FNDC3B in glioma using several databases and a variety of machine learning algorithms. RNA expression data and clinical information of 529 patients from the Cancer Genome Atlas (TCGA) and 1319 patients from Chinese Glioma Genome Atlas (CGGA) databases were downloaded for further investigation. To evaluate whether FNDC3B expression can predict clinical prognosis of glioma, we constructed a clinical nomogram to estimate long-term survival probabilities. The predicted nomogram was validated by CGGA cohorts. Differentially expressed genes (DEGs) were detected by the Wilcoxon test based on the TCGA-LGG dataset and the weighted gene co-expression network analysis (WGCNA) was implemented to identify the significant module associated with the expression level of FNDC3B. Furthermore, we investigated the correlation between FNDC3B with cancer immune infiltrates using TISIDB, ESTIMATE, and CIBERSORTx.

Results

Higher FNDC3B expression displayed a remarkably worse overall survival and the expression level of FNDC3B was an independent prognostic indicator for patients with glioma. Based on TCGA LGG dataset, a co-expression network was established and the hub genes were identified. FNDC3B expression was positively correlated to the tumor-infiltrating lymphocytes and immune infiltration score, and high FNDC3B expression was accompanied by the increased expression of B7-H3, PD-L1, TIM-3, PD-1, and CTLA-4. Moreover, expression of FNDC3B was significantly associated with infiltrating levels of several types of immune cells and most of their gene markers in glioma.

Conclusion

This study demonstrated that FNDC3B may be involved in the occurrence and development of glioma and can be regarded as a promising prognostic and immunotherapeutic biomarker for the treatment of glioma.

Global Transcriptomic Profiling Identifies Differential Gene Expression Signatures Between Inflammatory and Noninflammatory Aortic Aneurysms

OBJECTIVE

To identify hallmark genes and biomolecular processes in aortitis using high-throughput gene expression profiling, and to provide a range of potentially new drug targets (genes) and therapeutics from a pharmacogenomic network analysis.

METHODS

Bulk RNA sequencing was performed on surgically resected ascending aortic tissues from inflammatory aneurysms (giant cell arteritis [GCA] with or without polymyalgia rheumatica, n = 8; clinically isolated aortitis [CIA], n = 17) and noninflammatory aneurysms (n = 25) undergoing surgical aortic repair. Differentially expressed genes (DEGs) between the 2 patient groups were identified while controlling for clinical covariates. A protein-protein interaction model, drug-gene target information, and the DEGs were used to construct a pharmacogenomic network for identifying promising drug targets and potentially new treatment strategies in aortitis.

RESULTS

Overall, tissue gene expression patterns were the most associated with disease state than with any other clinical characteristic. We identified 159 and 93 genes that were significantly up-regulated and down-regulated, respectively, in inflammatory aortic aneurysms compared to noninflammatory aortic aneurysms. We found that the up-regulated genes were enriched in immune-related functions, whereas the down-regulated genes were enriched in neuronal processes. Notably, gene expression profiles of inflammatory aortic aneurysms from patients with GCA were no different than those from patients with CIA. Finally, our pharmacogenomic network analysis identified genes that could potentially be targeted by immunosuppressive drugs currently approved for other inflammatory diseases.

CONCLUSION

We performed the first global transcriptomics analysis in inflammatory aortic aneurysms from surgically resected aortic tissues. We identified signature genes and biomolecular processes, while finding that CIA may be a limited presentation of GCA. Moreover, our computational network analysis revealed potential novel strategies for pharmacologic interventions and suggests future biomarker discovery directions for the precise diagnosis and treatment of aortitis.

Survival of Stem Cells and Progenitors in the Intestine Is Regulated by LPA5-Dependent Signaling

BACKGROUND & AIMS

Regeneration of the epithelium by stem cells in the intestine is supported by intrinsic and extrinsic factors. Lysophosphatidic acid (LPA), a bioactive lipid mediator, regulates many cellular functions, including cell proliferation, survival, and cytokine secretion. Here, we identify LPA₅ receptor as a potent regulator of the survival of stem cells and transit-amplifying cells in the intestine.

METHODS

We have used genetic mouse models of conditional deletion of Lpar5, Lpar5^f/f;Rosa-Cre^ERT (Lpar5^KO), and intestinal epithelial cell-specific Lpar5^f/f;AhCre (Lpar5^IECKO) mice. Mice were treated with tamoxifen or β-naphthoflavone to delete Lpar5 expression. Enteroids derived from these mice were used to determine the effect of Lpar5 loss on the apoptosis and proliferation of crypt epithelial cells.

RESULTS

Conditional loss of Lpar5 induced ablation of the intestinal mucosa, which increased morbidity of Lpar5^KO mice. Epithelial regeneration was compromised with increased apoptosis and decreased proliferation of crypt epithelial cells by Lpar5 loss. Interestingly, intestinal epithelial cell-specific Lpar5 loss did not cause similar phenotypic defects in vivo. Lpar5 loss reduced intestinal stem cell marker gene expression and reduced lineage tracing from Lgr5⁺ ISCs. Lpar5 loss induced CXCL10 expression which exerts cytotoxic effects on intestinal stem cells and progenitors in the intestinal crypts. By co-culturing Lpar5^KO enteroids with wild-type or Lpar5^KO splenocytes, we demonstrated that lymphocytes protect the intestinal crypts via a LPA₅-dependent suppression of CXCL10.

CONCLUSIONS

LPA₅ is essential for the regeneration of intestinal epithelium. Our findings reveal a new finding that LPA₅ regulates survival of stem cells and transit-amplifying cells in the intestine.

What Is Currently Known about the Role of CXCL10 in SARS-CoV-2 Infection?

Dysregulation of the immune response plays an important role in the progression of SARS-CoV-2 infection. A "cytokine storm", which is a phenomenon associated with uncontrolled production of large amounts of cytokines, very often affects patients with COVID-19. Elevated activity of chemotactic cytokines, called chemokines, can lead to serious consequences. CXCL10 has an ability to activate its receptor CXCR3, predominantly expressed on macrophages, T lymphocytes, dendritic cells, natural killer cells, and B cells. So, it has been suggested that the chemokine CXCL10, through CXCR3, is associated with inflammatory diseases and may be involved in the development of COVID-19. Therefore, in this review paper, we focus on the role of CXCL10 overactivity in the pathogenesis of COVID-19. We performed an extensive literature search for our investigation using the MEDLINE/PubMed database. Increased concentrations of CXCL10 were observed in COVID-19. Elevated levels of CXCL10 were reported to be associated with a severe course and disease progression. Published studies revealed that CXCL10 may be a very good predictive biomarker of patient outcome in COVID-19, and that markedly elevated CXCL10 levels are connected with ARDS and neurological complications. It has been observed that an effective treatment for SARS-CoV-2 leads to inhibition of "cytokine storm", as well as reduction of CXCL10 concentrations. It seems that modulation of the CXCL10-CXCR3 axis may be an effective therapeutic target of COVID-19. This review describes the potential role of CXCL10 in the pathogenesis of COVID-19, as well as its potential immune-therapeutic significance. However, future studies should aim to confirm the prognostic, clinical, and therapeutic role of CXCL10 in SARS-CoV-2 infection.

Gene Expression of CD70 and CD27 Is Increased in Alopecia Areata Lesions and Associated with Disease Severity and Activity

Background

Alopecia areata (AA) is an acquired hair loss disorder induced by a cell-mediated autoimmune attack against anagen hair follicles. CD27-CD70 is a receptor-ligand complex which enhances T helper and cytotoxic T cell activation, survival, and proliferation. The overstimulation of this complex can lead to a lack of tolerance and the development of autoimmunity.

Objectives

This study aimed to assess the gene expression of CD27 and CD70 in patients with AA.

Methods

CD70 and CD27 mRNA expressions were evaluated by a quantitative real-time polymerase chain reaction in scalp biopsies from 40 AA patients (both AA lesions and non-lesional areas) and 40 healthy controls (HCs). The Severity of Alopecia Tool (SALT) score was used to assess AA severity. Patients were evaluated for signs of AA activity, including a positive hair pull test and dermoscopic features of black dots, broken hairs, and tapering hairs.

Results

The gene expression of CD70 and CD27 was significantly higher in AA lesions than in non-lesional areas (p < 0.001 for both) and HCs (p=0.004, p=0.014, respectively). There were significant positive correlations between AA severity and gene expression of CD70 (p < 0.001) and CD27 (p=0.030) in AA lesions. Significant associations were detected between signs of AA activity and lesional gene expression of CD70 and CD27. Additionally, CD70 and CD27 gene expression was significantly lower in non-lesional biopsies compared to HCs (p < 0.001).

Conclusion

Gene expression of CD70 and CD27 was increased in AA lesions and was associated with disease severity and activity. Thus, both molecules can be a predictor of AA severity and activity. Furthermore, the expression was reduced in non-lesional scalp areas. Thus, a lack of CD27 and CD70 expression may initially predispose to immunological dysregulation and the development of AA.

Single-cell analyses reveal key immune cell subsets associated with response to PD-L1 blockade in triple-negative breast cancer

In triple-negative breast cancer (TNBC), the benefit of combining chemotherapy with checkpoint inhibitors is still not very clear. We utilize single-cell RNA- and ATAC-sequencing to examine the immune cell dynamics in 22 patients with advanced TNBC treated with paclitaxel or its combination with the anti-PD-L1 atezolizumab. We demonstrate that high levels of baseline CXCL13⁺ T cells are linked to the proinflammatory features of macrophages and can predict effective responses to the combination therapy. In responsive patients, lymphoid tissue inducer (LTi) cells, follicular B (Bfoc) cells, CXCL13⁺ T cells, and conventional type 1 dendritic cells (cDC1) concertedly increase following the combination therapy, but instead decrease after paclitaxel monotherapy. Our data highlight the importance of CXCL13⁺ T cells in effective responses to anti-PD-L1 therapies and suggest that their reduction by paclitaxel regimen may compromise the clinical outcomes of accompanying atezolizumab for TNBC treatment.

Targeting the CD27-CD70 Pathway to Improve Outcomes in Both Checkpoint Immunotherapy and Allogeneic Hematopoietic Cell Transplantation

Immune checkpoint inhibitor therapies and allogeneic hematopoietic cell transplant (alloHCT) represent two distinct modalities that offer a chance for long-term cure in a diverse array of malignancies and have experienced many breakthroughs in recent years. Herein, we review the CD27-CD70 co-stimulatory pathway and its therapeutic potential in 1) combination with checkpoint inhibitor and other immune therapies and 2) its potential ability to serve as a novel approach in graft-versus-host disease (GVHD) prevention. We further review recent advances in the understanding of GVHD as a complex immune phenomenon between donor and host immune systems, particularly in the early stages with mixed chimerism, and potential novel therapeutic approaches to prevent the development of GVHD.

Innate-like Gene Expression of Lung-resident Memory CD8+ T-cells During Experimental Human Influenza: A Clinical Study

RATIONALE

Suboptimal vaccine immunogenicity and antigenic mismatch, compounded by poor uptake, means that influenza remains a major global disease. T-cells recognising peptides derived from conserved viral proteins could enhance vaccine-induced cross-strain protection.

OBJECTIVES

To investigate the kinetics, phenotypes and function of influenza virus-specific CD8+ resident-memory T-cells (Trm) in the lower airway and infer the molecular pathways associated with their response to infection in vivo.

METHODS

Healthy volunteers, aged 18-55, were inoculated intranasally with influenza A(H1N1)2009. Blood, upper and (in a subgroup) lower airway samples were obtained throughout infection. Symptoms were assessed using self-reported diaries and nasal viral load by qPCR. T-cell responses were analysed by three-colour FluoroSpot, flow cytometry with MHC I-peptide tetramers and RNAseq, with candidate markers confirmed using immunohistochemistry of endobronchial biopsies.

MEASUREMENTS AND MAIN RESULTS

Following challenge, 57% of participants became infected. Pre-existing influenza-specific CD8+ T-cells in blood correlated strongly with reduced viral load, which peaked at day 3. Influenza-specific CD8+ T-cells in BAL were highly enriched and predominantly expressed the Trm markers CD69 and CD103. Comparison between pre-infection CD8+ T-cells in BAL and blood by RNAseq revealed 3928 differentially expressed genes, including all major Trm cell markers. However, gene-set enrichment analysis of BAL CD8+ T-cells showed primarily innate cell-related pathways and, during infection, included upregulation of innate chemokines (Cxcl1, Cxcl10 and Cxcl16) that were also expressed by CD8+ cells in bronchial tissues.

CONCLUSIONS

CD8+ Trm cells in the human lung display innate-like gene and protein expression that demonstrates blurred divisions between innate and adaptive immunity. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02755948.

Landscape of Exhausted Virus-Specific CD8 T Cells in Chronic LCMV Infection

A hallmark of chronic infections is the presence of exhausted CD8 T cells, characterized by a distinct transcriptional program compared with functional effector or memory cells, co-expression of multiple inhibitory receptors, and impaired effector function, mainly driven by recurrent T cell receptor engagement. In the context of chronic lymphocytic choriomeningitis virus (LCMV) infection in mice, most studies focused on studying splenic virus-specific CD8 T cells. Here, we provide a detailed characterization of exhausted CD8 T cells isolated from six different tissues during established LCMV infection, using single-cell RNA sequencing. Our data reveal that exhausted cells are heterogeneous, adopt organ-specific transcriptomic profiles, and can be divided into five main functional subpopulations: advanced exhaustion, effector-like, intermediate, proliferating, or memory-like. Adoptive transfer experiments showed that these phenotypes are plastic, suggesting that the tissue microenvironment has a major impact in shaping the phenotype and function of virus-specific CD8 T cells during chronic infection.

MAIT cell activation augments adenovirus vector vaccine immunogenicity

Mucosal-associated invariant T (MAIT) cells are innate sensors of viruses and can augment early immune responses and contribute to protection. We hypothesized that MAIT cells may have inherent adjuvant activity in vaccine platforms that use replication-incompetent adenovirus vectors. In mice and humans, ChAdOx1 (chimpanzee adenovirus Ox1) immunization robustly activated MAIT cells. Activation required plasmacytoid dendritic cell (pDC)-derived interferon (IFN)-α and monocyte-derived interleukin-18. IFN-α-induced, monocyte-derived tumor necrosis factor was also identified as a key secondary signal. All three cytokines were required in vitro and in vivo. Activation of MAIT cells positively correlated with vaccine-induced T cell responses in human volunteers and MAIT cell-deficient mice displayed impaired CD8+ T cell responses to multiple vaccine-encoded antigens. Thus, MAIT cells contribute to the immunogenicity of adenovirus vectors, with implications for vaccine design.

Chemokine Signatures of Pathogen-Specific T Cells I: Effector T Cells

The choreography of complex immune responses, including the priming, differentiation, and modulation of specific effector T cell populations generated in the immediate wake of an acute pathogen challenge, is in part controlled by chemokines, a large family of mostly secreted molecules involved in chemotaxis and other patho/physiological processes. T cells are both responsive to various chemokine cues and a relevant source for certain chemokines themselves; yet, the actual range, regulation, and role of effector T cell-derived chemokines remains incompletely understood. In this study, using different in vivo mouse models of viral and bacterial infection as well as protective vaccination, we have defined the entire spectrum of chemokines produced by pathogen-specific CD8⁺ and CD4⁺T effector cells and delineated several unique properties pertaining to the temporospatial organization of chemokine expression patterns, synthesis and secretion kinetics, and cooperative regulation. Collectively, our results position the "T cell chemokine response" as a notably prominent, largely invariant, yet distinctive force at the forefront of pathogen-specific effector T cell activities and establish novel practical and conceptual approaches that may serve as a foundation for future investigations into the role of T cell-produced chemokines in infectious and other diseases.

Pediatric patients with acute lymphoblastic leukemia generate abundant and functional neoantigen-specific CD8+ T cell responses

Cancer arises from the accumulation of genetic alterations, which can lead to the production of mutant proteins not expressed by normal cells. These mutant proteins can be processed and presented on the cell surface by major histocompatibility complex molecules as neoepitopes, allowing CD8⁺ T cells to mount responses against them. For solid tumors, only an average 2% of neoepitopes predicted by algorithms have detectable endogenous antitumor T cell responses. This suggests that low mutation burden tumors, which include many pediatric tumors, are poorly immunogenic. Here, we report that pediatric patients with acute lymphoblastic leukemia (ALL) have tumor-associated neoepitope-specific CD8⁺ T cells, responding to 86% of tested neoantigens and recognizing 68% of the tested neoepitopes. These responses include a public neoantigen from the ETV6-RUNX1 fusion that is targeted in seven of nine tested patients. We characterized phenotypic and transcriptional profiles of CD8⁺ tumor-infiltrating lymphocytes (TILs) at the single-cell level and found a heterogeneous population that included highly functional effectors. Moreover, we observed immunodominance hierarchies among the CD8⁺ TILs restricted to one or two putative neoepitopes. Our results indicate that robust antitumor immune responses are induced in pediatric ALL despite their low mutation burdens and emphasize the importance of immunodominance in shaping cellular immune responses. Furthermore, these data suggest that pediatric cancers may be amenable to immunotherapies aimed at enhancing immune recognition of tumor-specific neoantigens.

SOCS3-deficient lung epithelial cells uptaking neutrophil-derived SOCS3 worsens lung influenza infection

Suppressor of cytokine signaling 3 (SOCS3) is a negative regulator of TBK1 and interferon pathway and the expression of SOCS3 is closely correlated with symptoms of influenza patients. However, whether deletion of Socs3 in the lung epithelial cells would affect influenza lung replication and inflammation in vivo is unknown. To test this, we approached the influenza infected Socs3^f/f and SpcCre.Socs3^f/f mice. We first found that knockdown of Socs3 in lung epithelial cells reduced influenza replication. However, in the in vivo study, there was a reduction of SOCS3 in the influenza-infected neutrophils coincided with an increase of SOCS3 in the CD45^-CD326⁺ lung epithelial cells in PR8-infected SpcCre.Socs3^f/f mice. SOCS3-deficient neutrophils expressed higher levels of IL-17 that enhanced chemokine expression in the lung epithelial cells. Lung SOCS3-dificient epithelial cells increased expression of GM-CSF and PGE₂ which promoted SpcCre.Socs3^f/f neutrophils to yield SOCS3. SpcCre.Socs3^f/f lung epithelial cells internalized SOCS3 released from GM-CSF + PGE₂-stimulated SpcCre.Socs3^f/f neutrophils, which could boost influenza replication in the lung epithelial cells. Thus, in the in vivo study, deletion of SOCS3 from lung epithelium could be nullified by the uptake from SOCS3 from infiltrated neutrophils. In addition, deletion of Socs3 from myeloid cells reduced lung influenza infection, but increased lung inflammation. Taken together, deletion of SOCS3 could suppress influenza replication, but intracellular SOCS3 communication between neutrophils and lung epithelial cells confounds this effect.

Ex vivo efficacy of BCMA-bispecific antibody TNB-383B in relapsed/refractory multiple myeloma

TNB-383B is a fully human BCMA-targeting T-cell engaging bispecific monoclonal antibody (T-BsAb). We assessed ex vivo efficacy of this drug to mediate killing of bone marrow mononuclear cells (BMMCs) freshly isolated from 10 patients with relapsed multiple myeloma (MM). BMMC were treated ex vivo with TNB-383B at doses ranging from 0.001-1 μg. Plasma cell (PC) lysis, viability, BCMA expression, CTL distribution, and degranulation were assessed by flow cytometry. Cytokine response to TNB-383B was quantified by multiplex protein assay. Dose-dependent PC lysis was triggered in all cases by TNB-383B at doses as low as 0.001 μg (P = .0102). Primary MM cells varied in BCMA expression. High BCMA+ PC count correlated with increased PC lysis (P = .005) and significant CTL degranulation specific to TNB-383B treatment (P = .0153 at 1 μg). High E:T ratio in bone marrow specimens led to lower viable and higher apoptotic PC compared with low E:T ratio (P < .001). Three cytokines were significantly modulated by TNB-383B: IL-2/TNFα increased by ∼4 ± 3.5-fold average (P < .005 at 1 μg) and IP10 increased by ∼50 ± 15-fold (P < .001 at 1 μg). We conclude that TNB-383B triggers primary PC lysis and CTL degranulation in a dose-dependent fashion ex vivo with no T cell expansion and mild increase of CRS-associated cytokines.

Homeostatic Cytokines Drive Epigenetic Reprogramming of Activated T Cells into a "Naive-Memory" Phenotype

Primary stimulation of T cells is believed to trigger unidirectional differentiation from naive to effector and memory subsets. Here we demonstrate that IL-7 can drive the phenotypic reversion of recently differentiated human central and effector memory CD8+ T cells into a naive-like phenotype. These "naive-revertant" cells display a phenotype similar to that of previously reported stem cell memory populations and undergo rapid differentiation and functional response following secondary challenge. The chromatin landscape of reverted cells undergoes substantial epigenetic reorganization with increased accessibility for cytokine-induced mediators such as STAT and closure of BATF-dependent sites that drive terminal differentiation. Phenotypic reversion may at least partly explain the generation of "stem cell memory" CD8+ T cells and reveals cells within the phenotypically naive CD8+ T cell pool that are epigenetically primed for secondary stimulation. This information provides insight into mechanisms that support maintenance of T cell memory and may guide therapeutic manipulation of T cell differentiation.

Regulators of T-cell fate: Integration of cell migration, differentiation and function

A fundamental question in immunology is how cells decide between distinct T helper, effector or memory differentiation fates. These decisions are paramount to overcome infection and establish long-lasting protection. The impact of cell location for the determination of T-cell fate decisions is an emerging field. This review will discuss our current understanding of the migration path that T cells follow, within draining lymph nodes, to steer differentiation down distinct paths of either effector or memory fates. In particular, the regulation of migration and cellular encounters mediated by the chemokine receptor CXCR3 and its ligands will be discussed. The combination of increased antigen density and unique cellular partners play a central role in facilitating the site-specific differentiation of effector T cells, within the interfollicular regions of draining lymph nodes. Recent advances have applied this knowledge to optimize vaccine design to target antigen to lymph nodes. Increased understanding of the regulation of CXCR3 ligands and how T cells integrate multiple chemokine cues will help further progress in this field and allow additional applications to direct cell differentiation outside the lymph node, to enhance memory residency in peripheral tissues and effector anti-tumor responses.

Chronic Ethanol Consumption Reduces Existing CD8 T Cell Memory and Is Associated with Lesions in Protection against Secondary Influenza A Virus Infections

Chronic alcohol consumption is associated with an increased incidence of disease severity during pulmonary infections. Our previous work in a mouse model of chronic alcohol consumption has detailed that the primary influenza A virus (IAV)-specific CD8 T cell response in mice that consumed ethanol (EtOH) had a reduced proliferative capacity as well as the ability to kill IAV target cells. Interestingly, recent studies have highlighted that human alcoholics have an increased susceptibility to IAV infections, even though they likely possess pre-existing immunity to IAV. However, the effects of chronic alcohol consumption on pre-existing immune responses (i.e., memory) to IAV have not been explored. Our results presented in this study show that IAV-immune mice that then chronically consumed alcohol (X31→EtOH) exhibited increased morbidity and mortality following IAV re-exposure compared with IAV-immune mice that had consumed water (X31→H₂O). This increased susceptibility in X31→EtOH mice was associated with reduced IAV-specific killing of target cells and a reduction in the number of IAV-specific CD8 T cells within the lungs. Furthermore, upon IAV challenge, recruitment of the remaining memory IAV-specific CD8 T cells into the lungs is reduced in X31→EtOH mice. This altered recruitment is associated with a reduced pulmonary expression of CXCL10 and CXCL11, which are chemokines that are important for T cell recruitment to the lungs. Overall, these results demonstrate that chronic alcohol consumption negatively affects the resting memory CD8 T cell response and reduces the ability of memory T cells to be recruited to the site of infection upon subsequent exposures, therein contributing to an enhanced susceptibility to IAV infections.

CD4+ T cell help in cancer immunology and immunotherapy

Cancer immunotherapy aims to promote the activity of cytotoxic T lymphocytes (CTLs) within a tumour, assist the priming of tumour-specific CTLs in lymphoid organs and establish efficient and durable antitumour immunity. During priming, help signals are relayed from CD4⁺ T cells to CD8⁺ T cells by specific dendritic cells to optimize the magnitude and quality of the CTL response. In this Review, we highlight the cellular dynamics and membrane receptors that mediate CD4⁺ T cell help and the molecular mechanisms of the enhanced antitumour activity of CTLs. We outline how deficient CD4⁺ T cell help reduces the response of CTLs and how maximizing CD4⁺ T cell help can improve outcomes in cancer immunotherapy strategies.

CD27 Promotes CD4+ Effector T Cell Survival in Response to Tissue Self-Antigen

Signaling through CD27 plays a role in T cell activation and memory. However, it is currently unknown how this costimulatory receptor influences CD4⁺ effector T (Teff) cells in inflamed tissues. In the current study, we used a murine model of inducible self-antigen expression in the epidermis to elucidate the functional role of CD27 on autoreactive Teff cells. Expression of CD27 on Ag-specific Teff cells resulted in enhanced skin inflammation when compared with CD27-deficient Teff cells. CD27 signaling promoted the accumulation of IFN-γ and IL-2-producing T cells in skin draining lymph nodes in a cell-intrinsic fashion. Surprisingly, this costimulatory pathway had minimal effect on early T cell activation and proliferation. Instead, signaling through CD27 resulted in the progressive survival of Teff cells during the autoimmune response. Using BH3 profiling to assess mitochondrial cell priming, we found that CD27-deficient cells were equally as sensitive as CD27-sufficient cells to mitochondrial outer membrane polarization upon exposure to either BH3 activator or sensitizer peptides. In contrast, CD27-deficient Teff cells expressed higher levels of active caspase 8. Taken together, these results suggest that CD27 does not promote Teff cell survival by increasing expression of antiapoptotic BCL2 family members but instead acts by preferentially suppressing the cell-extrinsic apoptosis pathway, highlighting a previously unidentified role for CD27 in augmenting autoreactive Teff cell responses.

Beyond PD-1/PD-L1 Inhibition: What the Future Holds for Breast Cancer Immunotherapy

Cancer immunotherapy has altered the management of human malignancies, improving outcomes in an expanding list of diseases. Breast cancer - presumably due to its perceived low immunogenicity - is a late addition to this list. Furthermore, most of the focus has been on the triple negative subtype because of its higher tumor mutational load and lymphocyte-enriched stroma, although emerging data show promise on the other breast cancer subtypes as well. To this point the clinical use of immunotherapy is limited to the inhibition of two immune checkpoints, Programmed Cell Death Protein 1 (PD-1) and Cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4). Consistent with the complexity of the regulation of the tumor - host interactions and their lack of reliance on a single regulatory pathway, combinatory approaches have shown improved efficacy albeit at the cost of increased toxicity. Beyond those two checkpoints though, a large number of co-stimulatory or co-inhibitory molecules play major roles on tumor evasion from immunosurveillance. These molecules likely represent future targets of immunotherapy provided that the promise shown in early data is translated into improved patient survival in randomized trials. The biological role, prognostic and predictive implications regarding breast cancer and early clinical efforts on exploiting these immune-related therapeutic targets are herein reviewed.

OMIC signatures to understand cancer immunosurveillance and immunoediting: Melanoma and immune cells interplay in immunotherapy

Melanoma is the deadliest form of skin cancer. Cutaneous melanomas usually originate from exposure to the mutagenic effects of ultraviolet radiation, and as such they exhibit the highest rate of somatic mutations than any other human cancer, and an extensive expression of neoantigens concurrently with a dense infiltrate of immune cells. The coexistence of high immunogenicity and high immune cell infiltration may sound contradictory for cancers carrying a gloomy outcome. However, recent studies have unveiled a variety of immunosuppressive mechanisms that often permeate the tumor microenvironment and that are responsible for tumor escaping from immunosurveillance mechanisms. Nonetheless, this particular immune profile has opened a new window of treatments based on immunotherapy that have significantly improved the clinical outcome of melanoma patients. Still, positive and complete therapy responses have been limited, and this particular cancer continues to be a major clinical challenge. The transcriptomic signatures of those patients with clinical benefit and those with progressive disease have provided a more complete picture of the universe of interactions between the tumor and the immune system. In this review, we integrate the results of the immunotherapy clinical trials to discuss a novel understanding of the mechanisms guiding cancer immunosurveillance and immunoediting. A clear notion of the cellular and molecular processes shaping how the immune system and the tumor are continuously coevolving would result in the rational design of combinatory therapies aiming to counteract the signaling pathways and cellular processes responsible for immunoescape mechanisms and provide clinical benefit to immunotherapy nonresponsive patients.

Integrin αvβ8-expressing tumor cells evade host immunity by regulating TGF-β activation in immune cells

TGF-β is a promising immunotherapeutic target. It is expressed ubiquitously in a latent form that must be activated to function. Determination of where and how latent TGF-β (L-TGF-β) is activated in the tumor microenvironment could facilitate cell- and mechanism-specific approaches to immunotherapeutically target TGF-β. Binding of L-TGF-β to integrin αvβ8 results in activation of TGF-β. We engineered and used αvβ8 antibodies optimized for blocking or detection, which - respectively - inhibit tumor growth in syngeneic tumor models or sensitively and specifically detect β8 in human tumors. Inhibition of αvβ8 potentiates cytotoxic T cell responses and recruitment of immune cells to tumor centers - effects that are independent of PD-1/PD-L1. β8 is expressed on the cell surface at high levels by tumor cells, not immune cells, while the reverse is true of L-TGF-β, suggesting that tumor cell αvβ8 serves as a platform for activating cell-surface L-TGF-β presented by immune cells. Transcriptome analysis of tumor-associated lymphoid cells reveals macrophages as a key cell type responsive to β8 inhibition with major increases in chemokine and tumor-eliminating genes. High β8 expression in tumor cells is seen in 20%-80% of various cancers, which rarely coincides with high PD-L1 expression. These data suggest tumor cell αvβ8 is a PD-1/PD-L1-independent immunotherapeutic target.

CD70 encoded by modified vaccinia virus Ankara enhances CD8 T-cell-dependent protective immunity in MHC class II-deficient mice

The immunological outcome of infections and vaccinations is largely determined during the initial first days in which antigen-presenting cells instruct T cells to expand and differentiate into effector and memory cells. Besides the essential stimulation of the T-cell receptor complex a plethora of co-stimulatory signals not only ensures a proper T-cell activation but also instils phenotypic and functional characteristics in the T cells appropriate to fight off the invading pathogen. The tumour necrosis factor receptor/ligand pair CD27/CD70 gained a lot of attention because of its key role in regulating T-cell activation, survival, differentiation and maintenance, especially in the course of viral infections and cancer. We sought to investigate the role of CD70 co-stimulation for immune responses induced by the vaccine vector modified vaccinia virus Ankara-Bavarian Nordic^® (MVA-BN^® ). Short-term blockade of CD70 diminished systemic CD8 T-cell effector and memory responses in mice. The dependence on CD70 became even more apparent in the lungs of MHC class II-deficient mice. Importantly, genetically encoded CD70 in MVA-BN^® not only increased CD8 T-cell responses in wild-type mice but also substituted for CD4 T-cell help. MHC class II-deficient mice that were immunized with recombinant MVA-CD70 were fully protected against a lethal virus infection, whereas MVA-BN^® -immunized mice failed to control the virus. These data are in line with CD70 playing an important role for vaccine-induced CD8 T-cell responses and prove the potency of integrating co-stimulatory molecules into the MVA-BN^® backbone.

Safety and Activity of Varlilumab, a Novel and First-in-Class Agonist Anti-CD27 Antibody, in Patients With Advanced Solid Tumors

Purpose

CD27, a costimulatory molecule on T cells, induces intracellular signals that mediate cellular activation, proliferation, effector function, and cell survival upon binding to its ligand, CD70. Varlilumab is a novel, first-in-class, agonist CD27 antibody that stimulates the CD27 pathway, which results in T-cell activation and antitumor activity in tumor models. This first-in-human, dose-escalation and expansion study evaluated the safety, pharmacology, and activity of varlilumab in patients with advanced solid tumors.

Methods

In a 3 + 3 dose-escalation design (n = 25), patients received a single dose of varlilumab (0.1, 0.3, 1.0, 3.0, or 10 mg/kg intravenously) with a 28-day observation, followed by up to five multidose cycles (one dose per week for 4 weeks), depending on tumor response. Expansion cohorts were initiated at 3.0 mg/kg in patients with melanoma (n = 16) and renal cell carcinoma (RCC; n = 15). Primary objectives were to assess the safety and the maximum tolerated and optimal biologic doses of varlilumab. Secondary objectives were to evaluate the pharmacokinetics, pharmacodynamics, and clinical antitumor activity of varlilumab.

Results

Exposure to varlilumab was linear and dose proportional across dose groups. Only one patient experienced a dose-limiting toxicity—grade 3 transient asymptomatic hyponatremia at the 1.0-mg/kg dose level. Treatment-related adverse events were generally grade 1 or 2 in severity. Evidence of biologic activity consistent with CD27 stimulation—chemokine induction, T-cell stimulation, regulatory T cell depletion—was observed at all dose levels. A patient with metastatic RCC experienced a partial response (78% shrinkage, progression-free survival > 2.3 years). Eight patients experienced stable disease > 3 months, including a patient with metastatic RCC with progression-free survival of > 3.9 years.

Conclusion

Dose escalation of varlilumab to 10 mg/kg was well tolerated without identification of a maximum tolerated dose. Varlilumab was biologically and clinically active.

Stimulating CD27 to quantitatively and qualitatively shape adaptive immunity to cancer

The capacity of the immune system to recognize and respond to tumors has been appreciated for over 100 years. However, clinical success has largely depended on the elucidation of the positive and negative regulators of effector cells after their activation via the antigen cell receptor. On the one hand, effector cells upregulate checkpoint molecules that are thought to play a role in limiting immunopathology. On the other, second and third waves of costimulation are often required to promote the expansion, survival and differentiation of effector cells. While it is clear that the immune system can be unleashed by blocking checkpoint molecules, this approach is most effective when pre-existing responses exist in patients' tumors. Thus, coordinating checkpoint blockade with costimulation could potentially expand the patient population that receives benefit from cancer immunotherapy. This review will discuss how the costimulatory molecule CD27 sculpts immunity and preclinical/clinical data indicating its potential for cancer immunotherapy and its clinical translation.

Low-dose prednisone and immunoglobulin G treatment for woman at risk for neonatal alloimmune thrombocytopenia and T helper 1 immunity

PROBLEM

Fetal and neonatal alloimmune thrombocytopenia is an alloimmune disorder resulting from platelet opsonization by maternal antibodies that destroy fetal platelets. As there is no antenatal screening or immunization to prevent sensitization, selection of high-risk population or the prevention of antenatal sensitization is significantly limited.

METHOD OF STUDY

(i) A case report of ante- and postnatal management of a woman with paternal homozygosity for human platelet antigen-1(HPA) incompatibility. (ii) A retrospective case-control study of 11 confirmed FNAIT patients, 8 possible-FNAIT women, and 10 women with confirmed ITP.

RESULT

Antenatal screening, prevention of maternal sensitization by serial monitoring and immunosuppression with prednisone and intravenous immunoglobulin G (IVIG) infusion resulted in two successful pregnancies without sensitization.

CONCLUSION

Screening for couples at risk and prednisone and/or IVIG treatment is an option for women with paternal homozygosity for offending HPA antigen to prevent antenatal sensitization. HPA incompatibility is associated with increased Th1 immunity and NK cell cytotoxicity.

HDAC Inhibitors Enhance T-Cell Chemokine Expression and Augment Response to PD-1 Immunotherapy in Lung Adenocarcinoma

PURPOSE

A significant limitation of checkpoint blockade immunotherapy is the relatively low response rate (e.g., ∼20% with PD-1 blockade in lung cancer). In this study, we tested whether strategies that increase T-cell infiltration to tumors can be efficacious in enhancing immunotherapy response.

EXPERIMENTAL DESIGN

We performed an unbiased screen to identify FDA-approved oncology agents with an ability to enhance T-cell chemokine expression with the goal of identifying agents capable of augmenting immunotherapy response. Identified agents were tested in multiple lung tumor models as single agents and in combination with PD-1 blockade. Additional molecular and cellular analysis of tumors was used to define underlying mechanisms.

RESULTS

We found that histone deacetylase (HDAC) inhibitors (HDACi) increased expression of multiple T-cell chemokines in cancer cells, macrophages, and T cells. Using the HDACi romidepsin in vivo, we observed increased chemokine expression, enhanced T-cell infiltration, and T-cell-dependent tumor regression. Importantly, romidepsin significantly enhanced the response to PD-1 blockade immunotherapy in multiple lung tumor models, including nearly complete rejection in two models. Combined romidepsin and PD-1 blockade also significantly enhanced activation of tumor-infiltrating T cells.

CONCLUSIONS

These results provide evidence for a novel role of HDACs in modulating T-cell chemokine expression in multiple cell types. In addition, our findings indicate that pharmacologic induction of T-cell chemokine expression represents a conceptually novel approach for enhancing immunotherapy response. Finally, these results suggest that combination of HDAC inhibitors with PD-1 blockade represents a promising strategy for lung cancer treatment. Clin Cancer Res; 22(16); 4119-32. ©2016 AACR.

A Higher Activation Threshold of Memory CD8+ T Cells Has a Fitness Cost That Is Modified by TCR Affinity during Tuberculosis

T cell vaccines against Mycobacterium tuberculosis (Mtb) and other pathogens are based on the principle that memory T cells rapidly generate effector responses upon challenge, leading to pathogen clearance. Despite eliciting a robust memory CD8⁺ T cell response to the immunodominant Mtb antigen TB10.4 (EsxH), we find the increased frequency of TB10.4-specific CD8⁺ T cells conferred by vaccination to be short-lived after Mtb challenge. To compare memory and naïve CD8⁺ T cell function during their response to Mtb, we track their expansions using TB10.4-specific retrogenic CD8⁺ T cells. We find that the primary (naïve) response outnumbers the secondary (memory) response during Mtb challenge, an effect moderated by increased TCR affinity. To determine whether the expansion of polyclonal memory T cells is restrained following Mtb challenge, we used TCRβ deep sequencing to track TB10.4-specific CD8⁺ T cells after vaccination and subsequent challenge in intact mice. Successful memory T cells, defined by their clonal expansion after Mtb challenge, express similar CDR3β sequences suggesting TCR selection by antigen. Thus, both TCR-dependent and -independent factors affect the fitness of memory CD8⁺ responses. The impaired expansion of the majority of memory T cell clonotypes may explain why some TB vaccines have not provided better protection.

CD8⁺ T cells are important for enforcing latency of tuberculosis, and for Mtb control in patients with HIV and low CD4 counts. While vaccines that primarily elicit CD4⁺ T cell responses have had difficulty preventing active pulmonary TB, a TB vaccine that elicits a potent memory CD8⁺ T cells is a logical alternative strategy. Memory T cells are thought to respond more rapidly than the primary (naïve) response. However, by directly comparing naïve and memory TCR retrogenic CD8⁺ T cells specific for the TB10.4 antigen during infection, we observe memory-derived T cells to be less fit than naïve-derived T cells. We relate the reduced fitness of memory CD8⁺ T cells to their lower sensitivity to antigen and show that fitness can be improved by increasing TCR affinity. Using a novel method for tracking CD8⁺ T cells elicited by vaccination during the response to Mtb aerosol challenge in intact mice, we observe the robust expansion of a new primary response as well as clonal selection of the secondary response, likely driven by TCR affinity. We propose that generating memory T cells with high affinities should be a goal of vaccination against TB.

Memory programming in CD8(+) T-cell differentiation is intrinsic and is not determined by CD4 help

CD8⁺ T cells activated without CD4⁺ T-cell help are impaired in memory expansion. To understand the underlying cellular mechanism, here we track the dynamics of helper-deficient CD8⁺ T-cell response to a minor histocompatibility antigen by phenotypic and in vivo imaging analyses. Helper-deficient CD8⁺ T cells show reduced burst expansion, rapid peripheral egress, delayed antigen clearance and continuous activation, and are eventually exhausted. Contrary to the general consensus that CD4 help encodes memory programmes in CD8⁺ T cells and helper-deficient CD8⁺ T cells are abortive, these cells can differentiate into effectors and memory precursors. Importantly, accelerating antigen clearance or simply increasing the burst effector size enables generation of memory cells by CD8⁺ T cells, regardless of CD4 help. These results suggest that the memory programme is CD8⁺ T-cell-intrinsic, and provide insight into the role of CD4 help in CD8⁺ T-cell responses.

Persistent antigen stimulation can cause exhaustion and unresponsiveness of CD8 cells, impairing the immune response. Here the authors show that increasing the number of CD8 cells, decreasing the antigen load or providing CD4 help can overcome the exhaustion and establish a memory response.

Gene expression studies of a human monocyte cell line identify dissimilarities between differently manufactured glatiramoids

Glatiramer Acetate (GA) has provided safe and effective treatment for multiple sclerosis (MS) patients for two decades. It acts as an antigen, yet the precise mechanism of action remains to be fully elucidated, and no validated pharmacokinetic or pharmacodynamic biomarkers exist. In order to better characterize GA’s biological impact, genome-wide expression studies were conducted with a human monocyte (THP-1) cell line. Consistent with previous literature, branded GA upregulated anti-inflammatory markers (e.g. IL10), and modulated multiple immune-related pathways. Despite some similarities, significant differences were observed between expression profiles induced by branded GA and Probioglat, a differently-manufactured glatiramoid purported to be a generic GA. Key results were verified using qRT-PCR. Genes (e.g. CCL5, adj. p < 4.1 × 10⁻⁵) critically involved in pro-inflammatory pathways (e.g. response to lipopolysaccharide, adj. p = 8.7 × 10⁻⁴) were significantly induced by Probioglat compared with branded GA. Key genes were also tested and confirmed at the protein level, and in primary human monocytes. These observations suggest differential biological impact by the two glatiramoids and warrant further investigation.