Systematic characterization of human CD8+ T cells with natural killer cell markers in comparison with natural killer cells and normal CD8+ T cells

KIR2DL5+CD8+ T cells associate with dietary lipid intake and are active in type 1 diabetes

BACKGROUND

Recent studies have shown that KIR+CD8+ T cells play a role in suppressing autoimmunity by eliminating pathogenic CD4+ T cells. However, their specific role in type 1 diabetes (T1D) remains unclear.

METHODS

In this study, we enrolled 108 patients diagnosed with T1D and 86 healthy individuals. We conducted flow cytometric analysis to examine the various subtypes of KIR+CD8+ T cells derived from peripheral blood mononuclear cells. Additionally, CD8+ T cells were isolated from the peripheral blood of T1D patients to assess the functions of different KIR+CD8+ T cell subtypes. To investigate the influence of lipids on the characteristics and activities of these T cell subtypes, the isolated CD8+ T cells were cultured with varying concentrations of palmitic acid (PA). Furthermore, we utilized an NSG (NOD scid gamma) mouse adoptive transfer model to assess the impact of dietary lipid intake on the functionality of KIR2DL5+CD8+ T cells in vivo.

RESULTS

We observed variations in circulating KIR+CD8+ T cell subtypes between patients with T1D and healthy controls. Notably, we observed a significant negative correlation between the frequencies of circulating KIR+CD8+ T cells and the titers of ZnT8 autoantibodies in individuals with T1D. Among these subtypes, KIR2DL5+CD8+ T cells demonstrated a positive association with dietary fat intake, characterized by increased perforin expression and reduced PD-1 expression. Importantly, KIR2DL5+CD8+ T cells exhibited enhanced proliferative capacity compared to other KIR+CD8+ T cell subsets. Palmitic acid (PA) was found to enhance the activation of KIR2DL5+CD8+ T cells and strengthened their ability to suppress CD4+ T cell proliferation in T1D patients. Moreover, dietary lipid intake significantly enhanced the functionality of KIR2DL5+CD8+ T cells in an NSG mouse adoptive transfer model.

CONCLUSION

Our findings suggest that lipid intake enhances the functionality of human KIR2DL5+CD8+ T cells and may offer implications for immunotherapy in T1D.

Increased donor inhibitory KIR are associated with reduced GVHD and improved survival following HLA-matched unrelated donor HCT in paediatric acute leukaemia

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated effects after haematopoietic stem cell transplantation (HCT). Previous work has shown that accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity in the adult transplant setting. Paediatric acute leukaemia patients were retrospectively analysed, and KIR-KIRL combinations and maximal inhibitory KIR ligand (IM-KIR) scores were determined. Clinical outcomes were examined using a series of graphs depicting clinical events and endpoints. The graph methodology demonstrated that prognostic variables significant in the occurrence of specific clinical endpoints remained significant for relevant downstream events. KIR-KIRL combinations were significantly predictive for reduced grade 3-4 aGVHD likelihood, in patients transplanted with increased inhibitory KIR gene content and IM-KIR = 5 scores. Improvements were also observed in associated outcomes for both ALL and AML patients, including relapse-free survival, GRFS and overall survival. This study demonstrates that NK cell KIR HLA interactions may be relevant to the paediatric acute leukaemia transplant setting. Reduction in aGVHD suggests KIR effects may extend beyond NK cells. Moving forward clinical trials utilizing donors with a higher iKIR should be considered for URD HCT in paediatric recipients with acute leukaemia to optimize clinical outcomes.

Multimeric immunotherapeutic complexes activating natural killer cells towards HIV-1 cure

BACKGROUND

Combination antiretroviral therapy (cART) has dramatically extended the life expectancy of people living with HIV-1 and improved their quality of life. There is nevertheless no cure for HIV-1 infection since HIV-1 persists in viral reservoirs of latently infected CD4+ T cells. cART does not eradicate HIV-1 reservoirs or restore cytotoxic natural killer (NK) cells which are dramatically reduced by HIV-1 infection, and express the checkpoint inhibitors NKG2A or KIR2DL upregulated after HIV-1 infection. Cytotoxic NK cells expressing the homing receptor CXCR5 were recently described as key subsets controlling viral replication.

METHODS

We designed and evaluated the potency of "Natural killer activating Multimeric immunotherapeutic compleXes", called as NaMiX, combining multimers of the IL-15/IL-15Rα complex with an anti-NKG2A or an anti-KIR single-chain fragment variable (scFv) to kill HIV-1 infected CD4+ T cells. The oligomerization domain of the C4 binding protein was used to associate the IL-15/IL-15Rα complex to the scFv of each checkpoint inhibitor as well as to multimerize each entity into a heptamer (α form) or a dimer (β form). Each α or β form was compared in different in vitro models using one-way ANOVA and post-hoc Tukey's tests before evaluation in humanized NSG tg-huIL-15 mice having functional NK cells.

RESULTS

All NaMiX significantly enhanced the cytolytic activity of NK and CD8+ T cells against Raji tumour cells and HIV-1+ ACH-2 cells by increasing degranulation, release of granzyme B, perforin and IFN-γ. Targeting NKG2A had a stronger effect than targeting KIR2DL due to higher expression of NKG2A on NK cells. In viral inhibition assays, NaMiX initially increased viral replication of CD4+ T cells which was subsequently inhibited by cytotoxic NK cells. Importantly, anti-NKG2A NaMiX enhanced activation, cytotoxicity, IFN-γ production and CXCR5 expression of NK cells from HIV-1 positive individuals. In humanized NSG tg-huIL-15 mice, we confirmed enhanced activation, degranulation, cytotoxicity of NK cells, and killing of HIV-1 infected cells from mice injected with the anti-NKG2A.α NaMiX, as compared to control mice, as well as decreased total HIV-1 DNA in the lung.

CONCLUSIONS

NK cell-mediated killing of HIV-1 infected cells by NaMiX represents a promising approach to support HIV-1 cure strategies.

Involvement of Innate Immune System in the Pathogenesis of Sepsis-Associated Acute Kidney Injury

Although experimental models have shown that the innate immune system is a main contributor to acute kidney injury (AKI), its involvement in human sepsis-associated AKI (SA-AKI) remains unclear. We retrospectively evaluated 19 patients with SA-AKI who were treated with continuous renal replacement therapy (CRRT). Serum cytokine, complement components, and the proportion and functions of innate immune cells, such as CD56+ T cells, CD56+ natural killer (NK) cells, and monocytes, were analyzed. There were no differences in the proportions of CD56+ T and NK cells between patients with SA-AKI and healthy controls. In patients with SA-AKI, fas ligand (FasL) expression in CD56+ T cells was significantly upregulated, and the proportion of perforin-positive CD56+ T cells tended to be higher than that in healthy controls. The positive rate of both FasL and perforin of CD56+ T cells was significantly higher than that of CD56- T cells, which include cytotoxic T cells. Antigen-presenting capacity and phagocytic activity of monocytes in patients with SA-AKI were significantly decreased compared to those of healthy controls and did not recover soon after the initiation of CRRT. CD56+ T cells are involved in the disease processes of human SA-AKI through effector molecules such as FasL or perforin.

Natural Killer T-like Cells: Immunobiology and Role in Disease

CD56+ T cells are generally recognized as a distinct population of T cells and are categorized as NKT-like cells. Although our understanding of NKT-like cells is far from satisfactory, it has been shown that aging and a number of disease situations have impacted these cells. To construct an overview of what is currently known, we reviewed the literature on human NKT-like cells. NKT-like cells are highly differentiated T cells with "CD1d-independent" antigen recognition and MHC-unrestricted cell killing. The genesis of NKT-like cells is unclear; however, it is proposed that the acquisition of innate characteristics by T cells could represent a remodeling process leading to successful aging. Additionally, it has been shown that NKT-like cells may play a significant role in several pathological conditions, making it necessary to comprehend whether these cells might function as prognostic markers. The quantification and characterization of these cells might serve as a cutting-edge indicator of individual immune health. Additionally, exploring the mechanisms that can control their killing activity in different contexts may therefore result in innovative therapeutic alternatives in a wide range of disease settings.

Antitumor Immunity Exerted by Natural Killer and Natural Killer T Cells in the Liver

The liver plays crucial roles in systemic immunity and greatly contributes to the systemic defense mechanism. Antitumor immunity in the liver is especially critical for the defense against systemic tumor cell dissemination. To achieve effective defense against metastatic tumor cells, liver immune cells with powerful cytotoxic activities construct a potent defense mechanism. In the liver, as compared with other organs, there is a significantly more intense percentage of innate immune lymphocytes, such as natural killer (NK) and NKT cells. These characteristic lymphocytes survey the portal blood transferred to the liver from the alimentary tract and eliminate malignant cells with their robust cytotoxic ability. Additionally, with their active cytokine-producing capacity, these innate lymphocytes initiate immunological sequences by adaptive immune cells. Therefore, they are crucial contributors to systemic antitumor immunity. These attractive immune cells help conduct a fundamental investigation of tumor immunity and act as a target of clinical measures for cancer therapies. This review discusses the mechanisms of these innate lymphocytes regarding recognition and cytotoxicity against tumor cells and the possibility of clinical applications for therapeutic measures.

Conversion of unresponsiveness to immune checkpoint inhibition by fecal microbiota transplantation in patients with metastatic melanoma: study protocol for a randomized phase Ib/IIa trial

BACKGROUND

The gut microbiome plays an important role in immune modulation. Specifically, presence or absence of certain gut bacterial taxa has been associated with better antitumor immune responses. Furthermore, in trials using fecal microbiota transplantation (FMT) to treat melanoma patients unresponsive to immune checkpoint inhibitors (ICI), complete responses (CR), partial responses (PR), and durable stable disease (SD) have been observed. However, the underlying mechanism determining which patients will or will not respond and what the optimal FMT composition is, has not been fully elucidated, and a discrepancy in microbial taxa associated with clinical response has been observed between studies. Furthermore, it is unknown whether a change in the microbiome itself, irrespective of its origin, or FMT from ICI responding donors, is required for reversion of ICI-unresponsiveness. To address this, we will transfer microbiota of either ICI responder or nonresponder metastatic melanoma patients via FMT.

METHODS

In this randomized, double-blinded phase Ib/IIa trial, 24 anti-PD1-refractory patients with advanced stage cutaneous melanoma will receive an FMT from either an ICI responding or nonresponding donor, while continuing anti-PD-1 treatment. Donors will be selected from patients with metastatic melanoma treated with anti-PD-1 therapy. Two patients with a good response (≥ 30% decrease according to RECIST 1.1 within the past 24 months) and two patients with progression (≥ 20% increase according to RECIST 1.1 within the past 3 months) will be selected as ICI responding or nonresponding donors, respectively. The primary endpoint is clinical benefit (SD, PR or CR) at 12 weeks, confirmed on a CT scan at 16 weeks. The secondary endpoint is safety, defined as the occurrence of grade ≥ 3 toxicity. Exploratory endpoints are progression-free survival and changes in the gut microbiome, metabolome, and immune cells.

DISCUSSION

Transplanting fecal microbiota to restore the patients' perturbed microbiome has proven successful in several indications. However, less is known about the potential role of FMT to improve antitumor immune response. In this trial, we aim to investigate whether administration of FMT can reverse resistance to anti-PD-1 treatment in patients with advanced stage melanoma, and whether the ICI-responsiveness of the feces donor is associated with its effectiveness.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05251389 (registered 22-Feb-2022). Protocol V4.0 (08-02-2022).

Pathophysiology of Sepsis and Genesis of Septic Shock: The Critical Role of Mesenchymal Stem Cells (MSCs)

The treatment of sepsis and septic shock remains a major public health issue due to the associated morbidity and mortality. Despite an improvement in the understanding of the physiological and pathological mechanisms underlying its genesis and a growing number of studies exploring an even higher range of targeted therapies, no significant clinical progress has emerged in the past decade. In this context, mesenchymal stem cells (MSCs) appear more and more as an attractive approach for cell therapy both in experimental and clinical models. Pre-clinical data suggest a cornerstone role of these cells and their secretome in the control of the host immune response. Host-derived factors released from infected cells (i.e., alarmins, HMGB1, ATP, DNA) as well as pathogen-associated molecular patterns (e.g., LPS, peptidoglycans) can activate MSCs located in the parenchyma and around vessels to upregulate the expression of cytokines/chemokines and growth factors that influence, respectively, immune cell recruitment and stem cell mobilization. However, the way in which MSCs exert their beneficial effects in terms of survival and control of inflammation in septic states remains unclear. This review presents the interactions identified between MSCs and mediators of immunity and tissue repair in sepsis. We also propose paradigms related to the plausible roles of MSCs in the process of sepsis and septic shock. Finally, we offer a presentation of experimental and clinical studies and open the way to innovative avenues of research involving MSCs from a prognostic, diagnostic, and therapeutic point of view in sepsis.

PD-L1+CD8+ T cells enrichment in lung cancer exerted regulatory function and tumor-promoting tolerance

Immunotherapy targeting checkpoint blockade to rescue T cells from exhaustion has become an essential therapeutic strategy in treating cancers. Till now, little is known about the PD-L1 graphic pattern and characteristics in CD8⁺ T cells. We combined cytometry by time-of-flight (CyTOF) and imaging mass cytometry (IMC) approaches to analyze CD8⁺ T cells from primary lung cancers and discovered that PD-L1⁺CD8⁺ T cells were enriched in tumor lesions, spatially localized with PD-1⁺CD8⁺ T cells. Furthermore, PD-L1⁺CD8⁺ T cells exerted regulatory functions that inhibited CD8⁺ T cells proliferation and cytotoxic abilities through the PD-L1/PD-1 axis. Moreover, tumor-derived IL-27 promotes PD-L1⁺CD8⁺ T cells development through STAT1/STAT3 signaling. Single-cell RNA sequencing data analysis further clarified PD-L1⁺CD8⁺ T cells elevated in the components related to downregulation of adaptive immune response. Collectively, our data demonstrated that PD-L1⁺CD8⁺ T cells enriched in lung cancer engaged in tolerogenic effects and may become a therapeutic target in lung cancer.

•

CyTOF and IMC revealed PD-L1⁺CD8⁺ T cells were enriched in human lung cancer

•

PD-L1⁺CD8⁺ T cells inhibited CD8⁺ T cells function through PD-1/PD-L1 axis

•

IL27 promoted PD-L1⁺CD8 T cells development through STAT1/STAT3 signaling

Zero-preserving imputation of single-cell RNA-seq data

A key challenge in analyzing single cell RNA-sequencing data is the large number of false zeros, where genes actually expressed in a given cell are incorrectly measured as unexpressed. We present a method based on low-rank matrix approximation which imputes these values while preserving biologically non-expressed genes (true biological zeros) at zero expression levels. We provide theoretical justification for this denoising approach and demonstrate its advantages relative to other methods on simulated and biological datasets.

Infections, Reactions of Natural Killer T Cells and Natural Killer Cells, and Kidney Injury

Natural killer T (NKT) cells and NK cells are representative innate immune cells that perform antitumor and antimicrobial functions. The involvement of these cells in various renal diseases, including acute kidney injury (AKI), has recently become evident. Murine NKT cells are activated and cause AKI in response to various stimuli, such as their specific ligand, cytokines, and bacterial components. Both renal vascular endothelial cell injury (via the perforin-mediated pathway) and tubular epithelial cell injury (via the tumor necrosis factor-alpha/Fas ligand pathway) are independently involved in the pathogenesis of AKI. NK cells complement the functions of NKT cells, thereby contributing to the development of infection-associated AKI. Human CD56⁺ T cells, which are a functional counterpart of murine NKT cells, as well as a subpopulation of CD56⁺ NK cells, strongly damage intrinsic renal cells in vitro upon their activation, possibly through mechanisms similar to those in mice. These cells are also thought to be involved in the acute exacerbation of pre-existing glomerulonephritis triggered by infection in humans, and their roles in sepsis-associated AKI are currently under investigation. In this review, we will provide an overview of the recent advances in the understanding of the association among infections, NKT and NK cells, and kidney injury, which is much more profound than previously considered. The important role of liver macrophages in the activation of NKT cells will also be introduced.

Effects of infliximab on lung and circulating natural killer cells, CD56+ T cells and B cells in sarcoidosis

Background

Tumour necrosis factor α (TNF-α) is pivotal in sarcoid granuloma formation, and inhibitors of TNF-α offer an attractive third-line treatment option in sarcoidosis. The sarcoid inflammation is characterised by an exaggerated T helper 1 response, and evidence indicates a contribution of dysregulated and/or deficient NK (natural killer) cells, CD56+ T cells and B cells.

Objectives

Insight into how TNF-α inhibitors influence these cells may provide more information on inflammatory mechanisms in sarcoidosis and improve understanding of such treatment. We therefore evaluated treatment effects of the TNF-α inhibitor infliximab on lung and peripheral blood (PB) NK, CD56+ T cells and B cells.

Methods

Fifteen patients were assessed with PB samples, spirometry and CT scan, and 11 of them also underwent bronchoalveolar lavage (BAL) close to start of infliximab treatment. These investigations were repeated after 6 months of treatment.

Results

Twelve out of 15 patients disclosed a clinical improvement at follow-up. Median percentage of BAL fluid (BALF) CD56+ T cells increased while a decrease was seen in PB (p<0.05 and 0.005, respectively). No significant changes were observed for NK cells. There was a trend towards increased median percentage of PB B cells (p=0.07), and a negative correlation was observed between PB and BALF B cells after treatment (p<0.05).

Conclusion

In conclusion, 6 months of infliximab treatment in patients with sarcoidosis, of whom the majority benefited from the treatment, influenced immune cells in the lung and circulation differently, highlighting the importance of investigating several compartments concomitantly when evaluating treatment effects on the inflammatory activity.

Association of Premature Immune Aging and Cytomegalovirus After Solid Organ Transplant

Immune function is altered with increasing age. Infection with cytomegalovirus (CMV) accelerates age-related immunological changes resulting in expanded oligoclonal memory CD8 T cell populations with impaired proliferation, signaling, and cytokine production. As a consequence, elderly CMV seropositive (CMV⁺) individuals have increased mortality and impaired responses to other infections in comparison to seronegative (CMV^–) individuals of the same age. CMV is also a significant complication after organ transplantation, and recent studies have shown that CMV-associated expansion of memory T cells is accelerated after transplantation. Thus, we investigated whether immune aging is accelerated post-transplant, using a combination of telomere length, flow cytometry phenotyping, and single cell RNA sequencing. Telomere length decreased slightly in the first year after transplantation in a subset of both CMV⁺ and CMV^– recipients with a strong concordance between CD57⁺ cells and short telomeres. Phenotypically aged cells increased post-transplant specifically in CMV⁺ recipients, and clonally expanded T cells were enriched for terminally differentiated cells post-transplant. Overall, these findings demonstrate a pattern of accelerated aging of the CD8 T cell compartment in CMV⁺ transplant recipients.

Fecal microbiota transplant overcomes resistance to anti-PD-1 therapy in melanoma patients

Anti-programmed cell death protein 1 (PD-1) therapy provides long-term clinical benefits to patients with advanced melanoma. The composition of the gut microbiota correlates with anti-PD-1 efficacy in preclinical models and cancer patients. To investigate whether resistance to anti-PD-1 can be overcome by changing the gut microbiota, this clinical trial evaluated the safety and efficacy of responder-derived fecal microbiota transplantation (FMT) together with anti-PD-1 in patients with PD-1-refractory melanoma. This combination was well tolerated, provided clinical benefit in 6 of 15 patients, and induced rapid and durable microbiota perturbation. Responders exhibited increased abundance of taxa that were previously shown to be associated with response to anti-PD-1, increased CD8+ T cell activation, and decreased frequency of interleukin-8-expressing myeloid cells. Responders had distinct proteomic and metabolomic signatures, and transkingdom network analyses confirmed that the gut microbiome regulated these changes. Collectively, our findings show that FMT and anti-PD-1 changed the gut microbiome and reprogrammed the tumor microenvironment to overcome resistance to anti-PD-1 in a subset of PD-1 advanced melanoma.

KIR+ CD8+ T Lymphocytes in Cancer Immunosurveillance and Patient Survival: Gene Expression Profiling

Simple Summary

Killer-cell immunoglobulin-like receptors (KIR) are molecules expressed by the most important cells of the immune system for cancer immune vigilance, natural killer (NK) and effector T cells. In this manuscript we study the role that cytotoxic CD8+ T cells expressing KIR receptors could play in cancer immune surveillance. With this objective, frequencies of different KIR+ CD8+ T cell subsets are correlated with the overall survival of patients with melanoma, ovarian and bladder carcinomas. In addition, the gene expression profile of KIR+ CD8+ T cell subsets related to the survival of patients is studied with the aim of discovering new therapeutic targets, so that the outcome of patients with cancer can be improved.

Abstract

Killer-cell immunoglobulin-like receptors (KIR) are expressed by natural killer (NK) and effector T cells. Although KIR+ T cells accumulate in oncologic patients, their role in cancer immune response remains elusive. This study explored the role of KIR+CD8+ T cells in cancer immunosurveillance by analyzing their frequency at diagnosis in the blood of 249 patients (80 melanomas, 80 bladder cancers, and 89 ovarian cancers), their relationship with overall survival (OS) of patients, and their gene expression profiles. KIR2DL1+ CD8+ T cells expanded in the presence of HLA-C2-ligands in patients who survived, but it did not in patients who died. In contrast, presence of HLA-C1-ligands was associated with dose-dependent expansions of KIR2DL2/S2+ CD8+ T cells and with shorter OS. KIR interactions with their specific ligands profoundly impacted CD8+ T cell expression profiles, involving multiple signaling pathways, effector functions, the secretome, and consequently, the cellular microenvironment, which could impact their cancer immunosurveillance capacities. KIR2DL1/S1+ CD8+ T cells showed a gene expression signature related to efficient tumor immunosurveillance, whereas KIR2DL2/L3/S2+CD8+ T cells showed transcriptomic profiles related to suppressive anti-tumor responses. These results could be the basis for the discovery of new therapeutic targets so that the outcome of patients with cancer can be improved.

CD8+ T cells are increased in the subventricular zone with physiological and pathological aging

Age-related cognitive decline and neurodegenerative diseases are associated with less functional neurogenic niches. It has been recently shown that aged subventricular zone (SVZ) suffers an infiltration of T cells, which affects neural stem cell activity in mice. Whether this occurs in human neurogenic niches or to which extent T-cell infiltration is also taking place in neurodegenerative diseases remains unknown. In this work, we studied the presence of T cells in both human neurogenic niches in young and old individuals. There was a significant increase in the number of CD3⁺ and CD8⁺ T cells in the SVZ of elderly individuals, which was not detected in the dentate gyrus. Moreover, we also found CD3⁺ and CD8⁺ T cells in the SVZ of individuals with neurodegenerative diseases. However, T-cell count was similar when compared non-neuropathological elderly with disease diagnosed patients. Our study reveals the infiltration of T cells in old human brains, particularly in the SVZ under non-pathological conditions and also in neurodegenerative contexts.

Multi-Dimensional Flow Cytometry Analyses Reveal a Dichotomous Role for Nitric Oxide in Melanoma Patients Receiving Immunotherapy

Phenotyping of immune cell subsets in clinical trials is limited to well-defined phenotypes, due to technological limitations of reporting flow cytometry multi-dimensional phenotyping data. We developed a multi-dimensional phenotyping analysis tool and applied it to detect nitric oxide (NO) levels in peripheral blood immune cells before and after adjuvant ipilimumab co-administration with a peptide vaccine in melanoma patients. We analyzed inhibitory and stimulatory markers for immune cell phenotypes that were felt to be important in the NO analysis. The pipeline allows visualization of immune cell phenotypes without knowledge of clustering techniques and to categorize cells by association with relapse-free survival (RFS). Using this analysis, we uncovered the potential for a dichotomous role of NO as a pro- and anti-melanoma factor. NO was found in subsets of immune-suppressor cells associated with shorter-term (≤ 1 year) RFS, whereas NO was also present in immune-stimulatory effector cells obtained from patients with significant longer-term (> 1 year) RFS. These studies provide insights into the cell-specific immunomodulatory role of NO. The methods presented herein can be applied to monitor the pro- and anti-tumor effects of a variety of immune-based therapeutics in cancer patients. Clinical Trial Registration Number: NCT00084656 (https://clinicaltrials.gov/ct2/show/NCT00084656).

Blockade of N-Glycosylation Promotes Antitumor Immune Response of T Cells

Adoptive cellular therapy and its derivative, chimeric AgR T cell therapy, have achieved significant progress against cancer. Major barriers persist, however, including insufficient induction of cytotoxic T cells and exhaustion of tumor-infiltrating lymphocytes. In this study, we discovered a new role for 2-deoxy-d-glucose (2DG) in enhancing the antitumor activity of human T cells against NKG2D ligand-expressing tumor cells. Human T cells treated with 2DG upregulated the NK-specific transcription factors TOX2 and EOMES, thereby acquiring NK cell properties, including high levels of perforin/granzyme and increased sensitivity to IL-2. Notably, rather than inhibiting glycolysis, 2DG modified N-glycosylation, which augmented antitumor activity and cell surface retention of IL-2R of T cells. Moreover, 2DG treatment prevented T cells from binding to galectin-3, a potent tumor Ag associated with T cell anergy. Our results, therefore, suggest that modifying N-glycosylation of T cells with 2DG could improve the efficacy of T cell-based immunotherapies against cancer.

Tuberculosis patients display a high proportion of CD8+ T cells with a high cytotoxic potential

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) and remains a major cause of morbidity and mortality worldwide. In the host's immune response system, T cells play a critical role in mediating protection against Mtb infection, but the role of CD8⁺ T cells is still controversial. We evaluated the phenotypical characterization and cytotoxic ability of CD8⁺ T cells by flow cytometry‐based assay. Cytokine levels in serum were measured by multiplex cytokine assay. Our data show that cells from TB patients have an increased percentage of peripheral blood CD8⁺αβ⁺ T (p = 0.02) and CD56⁺CD8⁺ T (p = 0.02) and a decreased frequency of NKG2D⁺CD8⁺ T (p = 0.02) compared with healthy donors. Unlike CD8⁺ T cells from healthy donors, CD8⁺ T cells from TB patients exhibit greater cytotoxicity, mediated by HLA class I molecules, on autologous monocytes in the presence of mycobacterial antigens (p = 0.005). Finally, TB patients have a proinflammatory profile characterized by serum high level of TNF‐α (p = 0.02) and IL‐8 (p = 0.0001), but, interestingly, IL‐4 (p = 0.002) was also increased compared with healthy donors. Our data show evidence regarding the highly cytotoxic status of CD8⁺ T cells in Mtb infection. These cytotoxic cells restricted to HLA‐A, B, and C could be used to optimize strategies for designing new TB vaccines or for identifying markers of disease progression.

Roles of Natural Killer T Cells and Natural Killer Cells in Kidney Injury

Mouse natural killer T (NKT) cells and natural killer (NK) cells are innate immune cells that are highly abundant in the liver. In addition to their already-known antitumor and antimicrobial functions, their pathophysiological roles in the kidney have recently become evident. Under normal circumstances, the proportion of activated NKT cells in the kidney increases with age. Administration of a synthetic sphingoglycolipid ligand (alpha-galactosylceramide) further activates NKT cells, resulting in injury to renal vascular endothelial cells via the perforin-mediated pathway and tubular epithelial cells via the TNF-α/Fas ligand pathway, causing acute kidney injury (AKI) with hematuria. Activation of NKT cells by common bacterial DNA (CpG-ODN) also causes AKI. In addition, NKT cells together with B cells play significant roles in experimental lupus nephritis in NZB/NZW F1 mice through their Th2 immune responses. Mouse NK cells are also assumed to be involved in various renal diseases, and there may be complementary roles shared between NKT and NK cells. Human CD56⁺ T cells, a functional counterpart of mouse NKT cells, also damage renal cells through a mechanism similar to that of mice. A subpopulation of human CD56⁺ NK cells also exert strong cytotoxicity against renal cells and contribute to the progression of renal fibrosis.

Truncated Robust Principal Component Analysis and Noise Reduction for Single Cell RNA Sequencing Data

The development of single cell RNA sequencing (scRNA-seq) has enabled innovative approaches to investigating mRNA abundances. In our study, we are interested in extracting the systematic patterns of scRNA-seq data in an unsupervised manner; thus, we have developed two extensions of robust principal component analysis (RPCA). First, we present a truncated version of RPCA (tRPCA), which is much faster and memory efficient. Second, we introduce a noise reduction in tRPCA with L₂ regularization. Unlike RPCA that only considers a low-rank L and sparse S matrices, the proposed method can also extract a noise E matrix inherent in modern genomic data. We demonstrate its usefulness by applying our methods on the peripheral blood mononuclear cell scRNA-seq data. Particularly, the clustering of a low-rank L matrix showcases better classification of unlabeled single cells. Overall, the proposed variants are well suited for high-dimensional and noisy data that are routinely generated in genomics.

The elusive case of human intraepithelial T cells in gut homeostasis and inflammation

The epithelial barrier of the gastrointestinal tract is home to numerous intraepithelial T cells (IETs). IETs are functionally adapted to the mucosal environment and are among the first adaptive immune cells to encounter microbial and dietary antigens. They possess hallmark features of tissue-resident T cells: they are long-lived nonmigratory cells capable of rapidly responding to antigen challenges independent of T cell recruitment from the periphery. Gut-resident T cells have been implicated in the relapsing and remitting course and persisting low-grade inflammation of chronic gastrointestinal diseases, including IBD and coeliac disease. So far, most data IETs have been derived from experimental animal models; however, IETs and the environmental makeup differ between mice and humans. With advances in techniques, the number of human studies has grown exponentially in the past 5 years. Here, we review the literature on the involvement of human IETs in gut homeostasis and inflammation, and how these cells are influenced by the microbiota and dietary antigens. Finally, targeting of IETs in therapeutic interventions is discussed. Broad insight into the function and role of human IETs in gut homeostasis and inflammation is essential to identify future diagnostic, prognostic and therapeutic strategies.

Tissue-Resident Lymphocytes Across Innate and Adaptive Lineages

Lymphocytes are an integral component of the immune system. Classically, all lymphocytes were thought to perpetually recirculate between secondary lymphoid organs and only traffic to non-lymphoid tissues upon activation. In recent years, a diverse family of non-circulating lymphocytes have been identified. These include innate lymphocytes, innate-like T cells and a subset of conventional T cells. Spanning the innate-adaptive spectrum, these tissue-resident lymphocytes carry out specialized functions and cross-talk with other immune cell types to maintain tissue integrity and homeostasis both at the steady state and during pathological conditions. In this review, we provide an overview of the heterogeneous tissue-resident lymphocyte populations, discuss their development, and highlight their functions both in the context of microbial infection and cancer.

Activated natural killer T cells in mice induce acute kidney injury with hematuria through possibly common mechanisms shared by human CD56+ T cells

Although activation of mouse natural killer T (NKT) cells by α-galactosylceramide (α-GalCer) causes failure of multiple organs, including the kidneys, the precise mechanisms underlying kidney injury remain unclear. Here, we showed that α-GalCer-activated mouse NKT cells injured both kidney vascular endothelial cells and tubular epithelial cells in vitro, causing acute kidney injury (AKI) with hematuria in middle-aged mice. The perforin-mediated pathway was mainly involved in glomerular endothelial cell injury, whereas the TNF-α/Fas ligand pathway played an important role in the injury of tubular epithelial cells. Kidney injury in young mice was mild but could be significantly exacerbated if NKT cells were strongly activated by NK cell depletion alone or in combination with IL-12 pretreatment. When stimulated by a combination of IL-2 and IL-12, human CD56⁺ T cells, a functional counterpart of mouse NKT cells, also damaged both glomerular endothelial cells and tubular epithelial cells, with the former being affected in a perforin-dependent manner. These data suggest that both mouse NKT cells and human CD56⁺ T cells are integral to the processes that mediate AKI. Targeting CD56⁺ T cells may, therefore, be a promising approach to treat AKI.

Antitumor activity of CD56-chimeric antigen receptor T cells in neuroblastoma and SCLC models

The CD56 antigen (NCAM-1) is highly expressed on several malignancies with neuronal or neuroendocrine differentiation, including small-cell lung cancer and neuroblastoma, tumor types for which new therapeutic options are needed. We hypothesized that CD56-specific chimeric antigen receptor (CAR) T cells could target and eliminate CD56-positive malignancies. Sleeping Beauty transposon-generated CD56R-CAR T cells exhibited αβT-cell receptors, released antitumor cytokines upon co-culture with CD56⁺ tumor targets, demonstrated a lack of fratricide, and expression of cytolytic function in the presence of CD56⁺ stimulation. The CD56R-CAR⁺ T cells are capable of killing CD56⁺ neuroblastoma, glioma, and SCLC tumor cells in in vitro co-cultures and when tested against CD56⁺ human xenograft neuroblastoma models and SCLC models, CD56R-CAR⁺ T cells were able to inhibit tumor growth in vivo. These results indicate that CD56-CARs merit further investigation as a potential treatment for CD56⁺ malignancies.

Diminished Frequency of Menstrual and Peripheral Blood NKT-Like Cells in Patients With Unexplained Recurrent Spontaneous Abortion and Infertile Women

Systemic monitoring of immune system may not precisely outline the local immune status in the uterus. This survey is a continuation of our previous studies on potential usefulness of menstrual blood (MB) immunophenotyping as a tool for investigation of immunological disturbances in pregnancy-related disorders. Peripheral blood (PB) and MB from healthy fertile (n = 15), unexplained recurrent spontaneous abortion (URSA; n = 15), and unexplained infertile women (n = 8) were collected simultaneously in the second day of their menstrual cycle and frequency of natural killer T (NKT)-like cell subpopulations were assessed by flow cytometry. Menstrual blood of all experimental groups contained higher percentage of TCRαβ⁺, CD45RO⁺, and CD16^- NKT-like cells compared to corresponding PB. Frequency of MB NKT-like cells in unexplained infertile participants was lower than fertile and URSA groups. Compared to normal participants, patients with URSA had lower frequency of PB TCRαβ⁺ and higher CD16⁺, while in infertile woman frequencies of PB CD45RO⁺, CD45RO^-, CD16^-, IL17⁺, and MB CD45RO⁺ NKT-like cells were lower. Although, PB and MB seemingly have the same histological nature, our results showed that MB contained different composition of NKT-like subsets with different cytokine profiles and could be viewed as one potential biological sample for evaluation of patients with infertility and URSA.

Assessment of Some Immune Parameters in Occupationally Exposed Nuclear Power Plants Workers: Flowcytometry Measurements of T, B, NK and NKT Cells

The purpose of this article is to analyze the results of a 10-year survey of the radiation effects of some immune parameters of occupationally exposed personnel from the Nuclear Power Plant “Kozloduy”, Bulgaria. 438 persons working in NPP with cumulative doses between 0.06 mSv and 766.36mSv and a control group with 65 persons were studied. Flow cytometry measurements of T, B, natural killer (NK) and natural killer T (NKT) cell lymphocyte populations were performed. Data were interpreted with regard to cumulative doses, length of service and age. The average values of the studied parameters of cellular immunity were in the reference range relative to age and for most of the workers were not significantly different from the control values. Low doses of ionizing radiation showed some trends of change in the number of CD3+CD4+ helper-inducer lymphocytes, CD3+ CD8+ and NKT cell counts. The observed changes in some of the studied parameters could be interpreted in terms of adaptation processes at low doses. At doses above 100–200 mSv, compensatory mechanisms might be involved to balance deviations in lymphocyte subsets. The observed variations in some cases could not be attributed only to the radiation exposure because of the impact of a number of other exogenous and endogenous factors on the immune system.

Comparative study of various subpopulations of cytotoxic cells in blood and ascites from patients with ovarian carcinoma

AIM OF THE STUDY

A number of observations have indicated that the immune system plays a significant role in patients with epithelial ovarian cancer (EOC). In cases of EOC, the prognostic significance of tumour infiltrating lymphocytes has not been clearly explained yet. The aim is to determine the phenotype and activation molecules of cytotoxic T cell and NK cell subpopulations and to compare their representation in malignant ascites and peripheral blood in patients with ovarian cancer.

MATERIAL AND METHODS

Cytotoxic cells taken from blood samples of the cubital vein and malignant ascites were obtained from 53 patients with EOC. Their surface and activation characteristics were determined by means of a flow cytometer. Immunophenotype multiparametric analysis of peripheral blood lymphocytes (PBLs) and tumour infiltrating lymphocytes (TILs) was carried out.

RESULTS

CD3(+) T lymphocytes were the main population of TILs (75.9%) and PBLs (70.9%). The number of activating T cells was significantly higher in TILs: CD3(+)/69(+) 6.7% vs. 0.8% (p < 0.001). The representation of (CD3(-)/16(+)56(+)) NK cells in TILs was significantly higher: 11.0% vs. 5.6% (p = 0.041); likewise CD56(bright) and CD-56(bright) from CD56(+) cells were higher in TILs (both p < 0.001). The activation receptor NKG2D was present in 45.1% of TILs vs. 32.3% of PBLs (p = 0.034), but we did not find a significant difference in the numbers of CD56(+)/NKG2D(+) in TILs and PBLs.

CONCLUSIONS

These results prove that the characteristics and intensity of anti-tumour responses are different in compared compartments (ascites/PBLs). The knowledge of phenotype and functions of effector cells is the basic precondition for understanding the anti-tumour immune response.

CD8(high)CD57(+) T-cell population as an independent predictor of response to chemoradiation therapy in extensive-stage small cell lung cancer

OBJECTIVES

Tangible clinical benefit is achieved in only a relatively small proportion of extensive-stage small cell lung cancer (SCLC) patients receiving current treatment strategies. Therefore, a more personalized use of current and novel treatment approaches is of critical importance. Individualized therapy relies on the identification of specific biomarkers predictive of response to a particular type of cancer treatment. Immune-related parameters emerge as powerful biomarkers among a variety of predictors of clinical response to various types of cancer treatment.

PATIENTS AND METHODS

Using multicolor flow cytometry, we evaluated a predictive value of CD8(high)CD57(+) T-cell population and its immunosuppressive (FOXP3(+), NKG2A(+)) and cytotoxic (Perforin(+)) subsets in the peripheral blood of extensive-stage SCLC patients (n=82) treated with either chemotherapy-alone (n=24), or chemoradiation therapy (n=42), or receiving best supportive care (n=16).

RESULTS

The low level (<20%) of CD8(high)CD57(+) T cells within the peripheral blood CD8(+) T-cell population and the low level (<3%) of the immunosuppressive FOXP3-positive subset within the CD8(high)CD57(+) T-cell population were independent predictors of a better response to treatment with chemoradiation therapy, but not with chemotherapy alone or best supportive care. Importantly there was no significant survival difference between SCLC patients who were: (i) treated with chemoradiation, but had an unfavourable immune profile (≥20% of CD8(high)CD57(+) T cells and ≥3% of its FOXP3-positive subset), (ii) treated with chemotherapy alone, or (iii) received best supportive care.

CONCLUSIONS

We show that only a combination of chemotherapy with radiation therapy offered a considerable survival benefit that was confined to a subset of extensive-stage SCLC patients with a favourable predictive immune profile in the peripheral blood.

Overexpression of IL-15 promotes tumor destruction via NK1.1+ cells in a spontaneous breast cancer model

BACKGROUND

Natural Killer (NK) cells play an important role in tumor prevention, but once tumors form, the numbers as well as the cytotoxic functions of NK cells are reduced. IL-15 is a cytokine that increases and activates NK cells. Here we will examine the anti-tumor role of IL-15 in a spontaneous breast cancer model.

METHODS

To achieve this, Polyoma Middle T (MT) mice that form spontaneous breast cancer were crossed with mice that either overexpress IL-15 (IL-15 transgenic (TG)) or mice that lack IL-15 (IL-15 knockout (KO)). We compared survival curves and tumor formation in IL-15 KO/MT, MT and IL-15 TG/MT groups. In addition, the phenotype, activation and contribution of NK cells and CD8 T cells to tumor formation were examined in each of these mouse strains via flow cytometry, ELISA, adoptive transfer and antibody depletion experiments.

RESULTS

IL-15KO/MT tumors formed and progressed to endpoint more quickly than MT tumors. These tumors displayed little apoptosis and poor CD8 T cell infiltration. In contrast, IL-15 TG/MT mice had increased survival and the tumors displayed extensive cell death, high proportions of activated NK cells and a higher infiltration of CD8 T cells than MT tumors. CD8 T cells in IL-15 TG/MT tumors were capable of secreting IFNγ, possessed markers of memory, did not display an exhausted phenotype and were frequently NK1.1+. Long-term antibody depletion studies in IL-15 TG/MT mice revealed that NK1.1+, but not CD8 T cells, were critical for tumor destruction. Lastly, human NK cells, when exposed to a similar cytokine environment as that found in IL-15TG/MT tumors, were capable of killing human breast cancer cells.

CONCLUSIONS

This study reveals that high levels of IL-15 can promote tumor destruction and reduce metastasis in breast cancer via effects on NK1.1+ cells. Our results suggest that strategies aimed at increasing NK cell activation may be effective against solid epithelial cancers.

CD1d levels in peripheral blood of patients with acute myeloid leukemia and acute lymphoblastic leukemia

The antitumor effect of natural killer T cells has been reported in several studies analyzing the expression of CD1d on antigen-presenting cells (APCs). Therefore, the present study questioned whether APCs may be abnormal in the peripheral blood (PB) of acute leukemia (AL) patients, particularly the levels of CD1d. To improve the understanding of the role of CD1d on APCs, the levels of CD1d on monocytes were analyzed in healthy controls, AL patients and AL patients with complete remission (CR). In addition, the correlation between the number of CD3⁺CD56⁺ T lymphocytes and levels of CD1d on monocytes was analyzed. Flow cytometry was used to determine the levels of CD1d on monocytes and lymphocytes. A significant decrease was observed in the levels of CD1d on monocytes in the PB of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) patients compared with the healthy controls. Simultaneously, significantly different levels of CD1d on monocytes were identified between the CR-AML and the CR-ALL patients; the levels of CD1d on monocytes remained low in the CR-AML patients, while the levels of CD1d on monocytes recovered in the CR-ALL patients. A significantly negative correlation was observed between the number of CD3⁺CD56⁺ T lymphocytes and the levels of CD1d on monocytes in AL patients. However, a significantly positive correlation was identified between the cytotoxicity of the CD3⁺CD56⁺ T lymphocytes and the levels of CD1d on monocytes. These results suggested that the significantly low levels of CD1d on monocytes may contribute to AML and ALL progression. In addition, a significant correlation was observed between the levels of CD1d on monocytes and the number/cytotoxicity of CD3⁺CD56⁺ T lymphocytes in AML and ALL patients.

Uncovering the pathogenesis of large granular lymphocytic leukemia-novel STAT3 and STAT5b mutations

Large granular lymphocytic (LGL) leukemia is an incurable chronic disease, characterized by clonal expansion of cytotoxic T- or NK-cells in blood and bone marrow. Cytopenias (anemia, neutropenia) and autoimmune disorders such as rheumatoid arthritis are the most common clinical manifestations of LGL leukemia. Recently, somatic activating STAT3 gene mutations were shown to be specific for LGL leukemia with a prevalence of up to 70%. Analogous mutations in the STAT5b gene were seen in a smaller proportion of patients. These gain-of-function mutations are located in the SH2 domain of STAT3 and affect the phosphotyrosine-SH2 interaction required for dimerization of STAT3. The mutations increase the phosphorylation of STAT3 and STAT5b and enhance the transcriptional activity of the mutated proteins. STAT3 and STAT5b mutations can be used as molecular markers for LGL leukemia diagnostics, and they present novel therapeutic targets for STAT3 and STAT5b inhibitors, which currently are in development for treatment of cancer and autoimmune disorders.

Perforin: a key pore-forming protein for immune control of viruses and cancer

Perforin (PFN) is the key pore-forming molecule in the cytotoxic granules of immune killer cells. Expressed only in killer cells, PFN is the rate-limiting molecule for cytotoxic function, delivering the death-inducing granule serine proteases (granzymes) into target cells marked for immune elimination. In this chapter we describe our current understanding of how PFN accomplishes this task. We discuss where PFN is expressed and how its expression is regulated, the biogenesis and storage of PFN in killer cells and how they are protected from potential damage, how it is released, how it delivers Granzymes into target cells and the consequences of PFN deficiency.

Interferon response factor 3 is crucial to poly-I:C induced NK cell activity and control of B16 melanoma growth

Interferon Response Factor 3 (IRF3) induces several NK-cell activating factors, is activated by poly-I:C, an experimental cancer therapeutic, but is suppressed during many viral infections. IRF3 Knockout (KO) mice exhibited enhanced B16 melanoma growth, impaired intratumoral NK cell infiltration, but not an impaired poly-I:C therapeutic effect due to direct suppression of B16 growth. IRF3 was responsible for poly-I:C decrease in TIM-3 expression by intratumoral dendritic cells, induction of NK-cell Granzyme B and IFN-γ, and induction of macrophage IL-12, IL-15, IL-6, and IRF3-dependent NK-activating molecule (INAM). Thus, IRF3 is a key factor controlling melanoma growth through NK-cell activities, especially during poly-I:C therapy.

Numbers and cytotoxicities of CD3+CD56+ T lymphocytes in peripheral blood of patients with acute myeloid leukemia and acute lymphocytic leukemia

Recent reports have highlighted the role of cellular immunity in anti-tumor defenses. T lymphocytes are known to play important part in anti-cancer immunity. The number and function of T lymphocytes are altered in chronic leukemia patients. CD3(+)CD56(+) T lymphocytes have also been found to be abnormal in cancer patients. We therefore investigated changes in the number and cytotoxicity of CD3(+)CD56(+) T lymphocytes in the peripheral blood of acute leukemia (AL) patients (excluding acute promyelocytic leukemia), to improve our understanding of the role of this T lymphocyte subset. We analyzed CD3(+)CD56(+) T lymphocyte numbers and cytotoxicities in healthy controls, AL patients, and AL patients with complete remission. Lymphocyte counts were performed in peripheral blood and flow cytometry was used to determine cell numbers and cytotoxicities. The absolute number of CD3(+)CD56(+) T lymphocytes was increased in AL patients (including acute myeloid [AML] and acute lymphocytic leukemia [ALL]) compared with healthy controls (P<0.05), but their functioning was significantly reduced (P<0.05). The number of CD3(+)CD56(+) T lymphocytes in AML and ALL patients who achieved remission following chemotherapy was close to healthy controls (P>0.05), but their functioning was still significantly reduced (P<0.05). In addition, the number of CD3(+)CD56(+) T lymphocytes increased significantly in AML patients with increased peripheral blood white blood cell (WBC) counts, and in ALL patients without increased WBCs. These results suggest that cellular immunity may respond to AML and ALL, but that lymphocyte cytotoxicity remains impaired. Dysfunction of CD3(+)CD56(+) T lymphocytes in AML and ALL patients may contribute to the failure of the host immune response against leukemic blasts.

Acute psychological stress increases peripheral blood CD3+CD56+ natural killer T cells in healthy men: possible implications for the development and treatment of allergic and autoimmune disorders

Acute psychological stress has primarily been investigated regarding its effects on conventional lymphocytes such as natural killer (NK) cells and CD4(+) and CD8(+) T cells. However, it might be important to focus on more "specialized" lymphocyte subsets, playing a role, for instance, in allergic conditions and autoimmunity, to identify links between stress, the immune system and somatic diseases. Using flow cytometry we determined frequencies of circulating T helper (Th)1-type (CD226(+)) and Th2-type (CRTH2(+)) T cells, γδ T cells, conventional CD56(+) natural killer T (NKT) cells and invariant NKT cells (iNKT) in healthy young males (N = 31; median age 26 years) undergoing a laboratory computer-based stressor lasting 12 min. We found that acute psychological stress induced a prolonged increase in CD4(+) and CD8(+) T cells expressing a Th2 phenotype. We also detected an acute increase in CD4(-) and CD8(-) double negative γδ T cells. Finally, we found that the well-known increase in NK cells under stressful conditions was paralleled by a significant increase in numbers of conventional CD56(+) NKT cells. In contrast, numbers of iNKT was not altered by stress. This study adds further evidence to a psychoneuroimmunological model proposing that under stressful conditions certain lymphocyte subsets, including iNKT and less mature T cells, are retained in lymphoid tissues while antigen-experienced effector-type T cells with a Th2 phenotype, γδ T cells and conventional CD56(+) NKT cells are mobilized into the peripheral blood. We suggest that in the case of frequent stress exposure, this might result in the promotion of, for example, allergic conditions.

Persistent accumulation of interferon-γ-producing CD8+CD56+ T cells in blood from patients with coronary artery disease

OBJECTIVE

There is emerging evidence for CD8(+) T cell alterations in blood from patients with coronary artery disease (CAD). We examined whether the distribution and phenotype of CD8(+)CD56(+) T cells differed according to the clinical manifestation of CAD.

METHODS

Patients with acute coronary syndrome (ACS, n = 30), stable angina (SA, n = 34) and controls (n = 36) were included. Blood was collected before and up to 12 months after referral for coronary investigation. CD8(+)CD56(+) T cells were assessed by flow cytometry for expression of surface markers, apoptosis, and intracellular expression of cytokines.

RESULTS

The proportions of CD8(+)CD56(+) T cells were significantly higher in both ACS and SA patients compared with controls, and remained so after 3 and 12 months. This was independent of age, sex, systemic inflammation and cytomegalovirus seropositivity. CD8(+)CD56(+) T cells differed from CD8(+)CD56(-) T cells in terms of lower CD28 expression and fewer apoptotic cells. Both CD8(+) T cell subsets were positive for interferon (IFN)-γ and tumor necrosis factor, although IFN-γ was significantly more confined to the CD8(+)CD56(+) T cells.

CONCLUSION

The persistent accumulation of CD8(+)CD56(+) T cells in ACS and SA patients share several features with immunological aging. It also contributes to a larger IFN-γ(+) pool in blood, and may thereby hypothetically drive the atherosclerotic process in a less favorable direction.

Adoptive T-cell therapy using autologous tumor-infiltrating lymphocytes for metastatic melanoma: current status and future outlook

Immunotherapy using autologous T cells has emerged to be a powerful treatment option for patients with metastatic melanoma. These include the adoptive transfer of autologous tumor-infiltrating lymphocytes (TILs), T cells transduced with high-affinity T cell receptors against major tumor antigens, and T cells transduced with chimeric antigen receptors composed of hybrid immunoglobulin light chains with endodomains of T-cell signaling molecules. Among these and other options for T-cell therapy, TILs together with high-dose interleukin 2 have had the longest clinical history with multiple clinical trials in centers across the world consistently demonstrating durable clinical response rates near 50% or more. A distinct advantage of TIL therapy making it still the T-cell therapy of choice is the broad nature of the T-cell recognition against both defined and undefined tumors antigens against all possible major histocompatibility complex, rather than the single specificity and limited major histocompatibility complex coverage of the newer T cell receptors and chimeric antigen receptor transduction technologies. In the past decade, significant inroads have been made in defining the phenotypes of T cells in TIL-mediating tumor regression. CD8+ T cells are emerging to be critical, although the exact subset of CD8+ T cells exhibiting the highest clinical activity in terms of memory and effector markers is still controversial. We present a model in which both effector-memory and more differentiated effector T cells ultimately may need to cooperate to mediate long-term tumor control in responding patients. Although TIL therapy has shown great potential to treat metastatic melanoma, a number of issues have emerged that need to be addressed to bring it more into the mainstream of melanoma care. First, we have a reached the point where a pivotal phase II or phase III trial is needed in an attempt to gain regulatory approval of TILs as standard of care. Second, improvements in how we expand TILs for therapy are needed that minimize the time the T cells are in culture and improve the memory and effector characteristics of the T cells for longer persistence and enhanced anti-tumor activity in vivo. Third, there is a critical need to identify surrogate and predictive biomarkers to better select suitable patients for TIL therapy to improve response rate and duration. Overall, the outlook for TIL therapy for melanoma is very bright. We predict that TILs will indeed emerge to become an approved treatment in the upcoming years through pivotal clinical trials. Moreover, new approaches combining TILs with targeted signaling pathway drugs, such as mutant B-RAF inhibitors, and synergistic immunomodulatory interventions enhancing T-cell costimulation and preventing negative regulation should further increase therapeutic efficacy and durable complete response rates.

Interpreting NK cell transcripts versus T cell transcripts in renal transplant biopsies

NK cell transcripts are increased in biopsies with antibody-mediated rejection, whereas T cell transcripts are increased in T cell-mediated rejection. However, NK and T cells share many features, creating potential ambiguity. Therefore to estimate the NK- versus T cell transcript burdens separately, we defined nonoverlapping transcripts selective for NK cells (N = 4) or T cells (N = 5). We compared NK- versus T cell transcript burdens in microarrays from 403 kidney transplant biopsies (182 early, 221 late). In late biopsies, high NK-cell transcript expression was associated with antibody-mediated rejection, correlating with microvascular inflammation and donor specific HLA antibody. However, some early biopsies with T cell-mediated rejection had high NK-cell transcript expression, as well as T cell transcripts, without evidence of antibody-mediated rejection or DSA, correlating with interstitial inflammation and tubulitis. Both NK-cell and T cell transcripts were moderately increased in many kidneys with inflammation secondary to injury or atrophy scarring. These results support the distinct role of NK cells in late antibody-mediated rejection, but indicate a role for NK-transcript expressing cells (NK cells or T cells with NK features) both in T cell-mediated rejection and in inflammation associated with injury and atrophy scarring.

Detection and characterization of a novel subset of CD8⁺CD57⁺ T cells in metastatic melanoma with an incompletely differentiated phenotype

PURPOSE

Tumor-specific T cells are frequently induced naturally in melanoma patients and infiltrate tumors. It is enigmatic why these patients fail to experience tumor regression. Given that CD8(+) T cells mediate antigen-specific killing of tumor cells, the focus of this study was to identify alterations in the differentiation of CD8(+) residing at the tumor site, with emphasis on a population expressing CD57, a marker for terminal differentiation.

EXPERIMENTAL DESIGN

We conducted flow cytometric analysis of CD8(+) tumor-infiltrating lymphocytes (TIL) isolated from 44 resected melanoma metastases with known T-cell differentiation markers. For comparison, peripheral blood mononuclear cells were isolated from matched melanoma patients. We sorted different CD8(+) subsets found in TIL and determined their effector functions. In addition, we carried out Vβ clonotype expression analysis of T-cell receptors to determine lineage relationship between the CD8(+) TIL subsets.

RESULTS

The majority of CD8(+) TIL was in the early-effector memory stage of differentiation. A significant population consisted of an oligoclonal subset of cells coexpressing CD27, CD28, CD57, and Granzyme B, with little or no perforin. These cells could be induced to proliferate, produce a high level of IFN-γ, and differentiate into CD27(-)CD57(+), perforin(high) mature CTL in vitro. Addition of TGF-β1 prevented further differentiation.

CONCLUSIONS

Our studies identified a novel subset of incompletely differentiated CD8(+) CTL coexpressing early effector memory and late CTL markers. This population resembles that found in patients with uncontrolled chronic viral infections. TGF-β1, frequently produced by melanoma tumors, may be a key cytokine inhibiting further maturation of this subset.

Natural killer T cells in pulmonary disorders

Natural killer T (NKT) cells, a unique subgroup of lymphocytes with features of both T and natural killer (NK) cells, represent a bridge between innate and adaptive immunity. They have the ability to either promote or suppress immune responses. With these immunoregulatory functions, NKT cells have emerged as an important subset of lymphocytes with a protective role in some disorders, such as infections, cancer, and possibly sarcoidosis, and a pathogenic role in others, such as asthma, chronic obstructive pulmonary disease and hypersensitivity pneumonitis. Immunotherapeutic interventions to modulate the immune response by targeting iNKT cell functions has become a challenging field and has shown promising results for the development of new therapies.

Antitumor immunity produced by the liver Kupffer cells, NK cells, NKT cells, and CD8 CD122 T cells

Mouse and human livers contain innate immune leukocytes, NK cells, NKT cells, and macrophage-lineage Kupffer cells. Various bacterial components, including Toll-like receptor (TLR) ligands and an NKT cell ligand (α-galactocylceramide), activate liver Kupffer cells, which produce IL-1, IL-6, IL-12, and TNF. IL-12 activates hepatic NK cells and NKT cells to produce IFN-γ, which further activates hepatic T cells, in turn activating phagocytosis and cytokine production by Kupffer cells in a positive feedback loop. These immunological events are essentially evoked to protect the host from bacterial and viral infections; however, these events also contribute to antitumor and antimetastatic immunity in the liver by activated liver NK cells and NKT cells. Bystander CD8⁺CD122⁺ T cells, and tumor-specific memory CD8⁺T cells, are also induced in the liver by α-galactocylceramide. Furthermore, adoptive transfer experiments have revealed that activated liver lymphocytes may migrate to other organs to inhibit tumor growth, such as the lungs and kidneys. The immunological mechanism underlying the development of hepatocellular carcinoma in cirrhotic livers in hepatitis C patients and liver innate immunity as a double-edged sword (hepatocyte injury/regeneration, septic shock, autoimmune disease, etc.) are also discussed.

Fine phenotypic and functional characterization of effector cluster of differentiation 8 positive T cells in human patients with primary biliary cirrhosis

In primary biliary cirrhosis (PBC), patients develop a multilineage response to a highly restricted peptide of the E2 component of pyruvate dehydrogenase (PDC-E2) involving autoantibody and autoreactive cluster of differentiation (CD)4(+) and CD8(+) T-cell responses. Recent data from murine models have suggested that liver-infiltrating CD8(+) cells play a critical role in biliary destruction in PBC. We hypothesized that chronic antigen stimulation of CD8(+) T cells alters effector memory T cell (T(EM) ) frequency and function similar to that seen with chronic viral infections, including failure to terminally differentiate and relative resistance to apoptosis. We have rigorously phenotyped CD8(+) T-cell subpopulations from 132 subjects, including 76 patients with PBC and 56 controls, and report a higher frequency of T(EM) cells characterized as CD45RO(high) CD57(+) CD8(high), but expressing the gut homing integrin, α4β7, in peripheral blood mononuclear cells of PBC. These CD8(high) T(EM) cells have reduced expression of Annexin V after TCR stimulation. Consistent with a T(EM) phenotype, CD45RO(high) CD57(+) CD8(high) T cells express higher levels of granzyme A, granzyme B, perforin, CCR5 and α4β7, and lower levels of CCR7 and CD28 than other CD8(high) T cells. Furthermore, interleukin (IL)-5 produced by CD8(+) CD57(+) T lymphocytes upon in vitro T-cell receptor stimulation are increased in PBC. Histologically, CD8(+) CD57(+) T cells accumulate around the portal area in PBC. Moreover, CD8(+) CD57(+) T cells respond specifically to the major histocompatibility class I epitope of PDC-E2.

CONCLUSION

In conclusion, our data demonstrate that CD45RO(high) CD57(+) CD8(high) T cells are a subset of terminally differentiated cytotoxic T(EM) cells, which could play a critical role in the progressive destruction of biliary epithelial cells.

CD8+ CD28- and CD8+ CD57+ T cells and their role in health and disease

Chronic antigenic stimulation leads to gradual accumulation of late-differentiated, antigen-specific, oligoclonal T cells, particularly within the CD8(+) T-cell compartment. They are characterized by critically shortened telomeres, loss of CD28 and/or gain of CD57 expression and are defined as either CD8(+) CD28(-) or CD8(+) CD57(+) T lymphocytes. There is growing evidence that the CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population plays a significant role in various diseases or conditions, associated with chronic immune activation such as cancer, chronic intracellular infections, chronic alcoholism, some chronic pulmonary diseases, autoimmune diseases, allogeneic transplantation, as well as has a great influence on age-related changes in the immune system status. CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population is heterogeneous and composed of various functionally competing (cytotoxic and immunosuppressive) subsets thus the overall effect of CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell-mediated immunity depends on the predominance of a particular subset. Many articles claim that CD8(+) CD28(-) (CD8(+) CD57(+)) T cells have lost their proliferative capacity during process of replicative senescence triggered by repeated antigenic stimulation. However recent data indicate that CD8(+) CD28(-) (CD8(+) CD57(+)) T cells can transiently up-regulate telomerase activity and proliferate under certain stimulation conditions. Similarly, conflicting data is provided regarding CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell sensitivity to apoptosis, finally leading to the conclusion that this T-cell population is also heterogeneous in terms of its apoptotic potential. This review provides a comprehensive approach to the CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population: we describe in detail its origins, molecular and functional characteristics, subsets, role in various diseases or conditions, associated with persistent antigenic stimulation.

Mixed chimerism, lymphocyte recovery, and evidence for early donor-specific unresponsiveness in patients receiving combined kidney and bone marrow transplantation to induce tolerance

BACKGROUND

We have previously reported operational tolerance in patients receiving human leukocyte antigen-mismatched combined kidney and bone marrow transplantation (CKBMT). We now report on transient multilineage hematopoietic chimerism and lymphocyte recovery in five patients receiving a modified CKBMT protocol and evidence for early donor-specific unresponsiveness in one of these patients.

METHODS

Five patients with end-stage renal disease received CKBMT from human leukocyte antigen-mismatched, haploidentical living-related donors after modified nonmyeloablative conditioning. Polychromatic flow cytometry was used to assess multilineage chimerism and lymphocyte recovery posttransplant. Limiting dilution analysis was used to assess helper T-lymphocyte reactivity to donor antigens.

RESULTS

Transient multilineage mixed chimerism was observed in all patients, but chimerism became undetectable by 2 weeks post-CKBMT. A marked decrease in T- and B-lymphocyte counts immediately after transplant was followed by gradual recovery. Initially, recovering T cells were depleted of CD45RA+/CD45RO(-) "naïve-like" cells, which have shown strong recovery in two patients, and CD4:CD8 ratios increased immediately after transplant but then declined markedly. Natural killer cells were enriched in the peripheral blood of all patients after transplant.For subject 2, a pretransplant limiting dilution assay revealed T helper cells recognizing both donor and third-party peripheral blood mononuclear cells. However, the antidonor response was undetectable by day 24, whereas third-party reactivity persisted.

CONCLUSION

These results characterize the transient multilineage mixed hematopoietic chimerism and recovery of lymphocyte subsets in patients receiving a modified CKBMT protocol. The observations are relevant to the mechanisms of donor-specific tolerance in this patient group.

A simplified method for the clinical-scale generation of central memory-like CD8+ T cells after transduction with lentiviral vectors encoding antitumor antigen T-cell receptors

Adoptive transfer of antigen-specific CD8+ T cells can effectively treat patients with metastatic melanoma. Recent efforts have emphasized the in vitro generation of antitumor T cells by transduction of genes encoding antitumor T-cell receptors. At present, lentiviral vector-mediated transduction of CD8+ T cells relies on anti-CD3/CD28 bead stimulation; however, this method fails to efficiently expand CD8+ T cells. Herein we sought to establish a methodology for lentiviral vector transduction using optimal activating agents for efficient gene delivery and robust expansion of CD8+ T cells. To overcome the inability of anti-CD3/CD28 beads to efficiently expand CD8+ T cells, we evaluated alternative activating agents including feeder cells from allogeneic peripheral blood mononuclear cells and plate-bound anti-CD3 antibody. Analyses of gene transfer, cell phenotype, fold expansion, and biologic activities were used to determine the optimal methodology. Plate-bound anti-CD3 provided an ideal activation platform that afforded optimal lentiviral vector-mediated gene transfer efficiency (up to 90%), and coupled with peripheral blood mononuclear cells feeder cells yielded up to 600-fold expansion of CD8+ T cells within 12 days. The T-cell antigen receptor (TCR) engineered CD8+ T cells conferred specific antitumor activity and many displayed a central memory-like phenotype. The methodology described here could be readily applied for engineering CD8+ T cells with antitumor specificity for human adoptive immunotherapy.

The small heat shock protein 27 is a key regulator of CD8+ CD57+ lymphocyte survival

Differences in CD8(+)CD57(-) and CD8(+)CD57(+) lymphocyte lifespan have been documented. Lower numbers and shorter lifespan are characteristic of CD8(+)CD57(+) in normal individuals. However, CD8(+)CD57(+) are expanded in certain disease states including T cell large granular leukemia and other hematologic malignancies. The mechanisms responsible for the differences in CD8(+)CD57(-) and CD8(+)CD57(+) lifespan remain elusive. In this study, we demonstrate that the small heat shock protein (Hsp) 27 is a key regulator of CD8(+)CD57(+) lymphocyte lifespan. We found that Hsp27 expression is significantly lower in CD8(+)CD57(+) than in CD8(+)CD57(-) lymphocytes. In contrast, Hsp60 and Hsp70 are expressed at comparable levels. Unlike other antiapoptotic Bcl-2-like molecules, the expression of Hsp27 tightly correlates with CD8(+)CD57(+) and CD8(+)CD57(-) lifespan. We demonstrate that Hsp27 overexpression in CD8(+)CD57(+) lymphocytes to levels found normally in CD8(+)CD57(-) lymphocytes decreased apoptosis. Accordingly, silencing of Hsp27 in CD8(+)CD57(-) lymphocytes increased apoptosis. Collectively these results demonstrate that Hsp27 is a critical regulator of normal CD8(+)CD57(+) lifespan supporting its use as a marker of lifespan in this lineage, and suggest a mechanism responsible for the decreased apoptosis and clonal expansion characteristic of certain disease states.