Spontaneous human lymphocyte-mediated cytotoxicity against tumor target cells. IX. The quantitation of natural killer cell activity

NK Cytotoxicity Mediated by NK-92 Cell Lines Expressing Combinations of Two Allelic Variants for FCGR3

Natural killer (NK) cells play an important role in the surveillance of viral infections and cancer. NK cell antibody-dependent cellular cytotoxicity (ADCC) and direct cytotoxicity are mediated by the recognition of antibody-coated target cells through the Fc gamma receptor IIIA (FcγRIIIa/CD16) and by ligands of activating/inhibitory NK receptors, respectively. Allelic variants of the FCGR3A gene include the high-affinity single-nucleotide polymorphism (SNP) rs396991 (V176F), which is associated with the efficacy of monoclonal antibody (mAb) therapies, and the SNP rs10127939 (L66H/R). The contribution of FCGR3A SNPs to NK cell effector functions remains controversial; therefore, we generated a panel of eight NK-92 cell lines expressing specific combinations of these SNPs and tested their cytotoxicities. NK-92 cells were stably transfected with plasmids containing different combinations of FCGR3A SNPs. Messenger RNA and FcγRIIIa/CD16 cell surface expressions were detected using new generation sequencing (NGS) and flow cytometry, respectively. All FcγRIIIa/CD16-transfected NK-92 cell lines exhibited robust ADCC against three different target cell lines with minor differences. In addition, enhanced direct NK cytotoxicity against K562 target cells was observed, suggesting a mechanistic role of FcγRIIIa/CD16 in direct NK cytotoxicity. In conclusion, we generated eight FcγRIIIa/CD16-transfected NK-92 cell lines carrying different combinations of two of the most studied FCGR3A SNPs, representing the major genotypes described in the European population. The functional characterization of these cell lines revealed differences in ADCC and direct NK cytotoxicity that may have implications for the design of adoptive cancer immunotherapies using NK cells and tumor antigen-directed mAbs.

Evaluation of resazurin phenoxazine dye as a highly sensitive cell viability potency assay for natural killer cell-derived extracellular vesicle-based cancer biotherapeutics

Natural killer cell-derived extracellular vesicles (NK-EVs) are candidate biotherapeutics against various cancers. However, standardised potency assays are necessary for a reliable assessment of NK-EVs' cytotoxicity. This study aims to thoroughly evaluate a highly sensitive resazurin phenoxazine-based cell viability potency assay (measurement of the cellular redox metabolism) for quantifying the cytotoxicity of NK-EVs against leukaemia K562 cells (suspension model) and breast cancer MDA-MB-231 cells (adherent model) in vitro. The assay was evaluated based on common analytical parameters setforth by regulatory guidelines, including specificity, selectivity,accuracy, precision, linearity, range and stability. Our results revealed that this resazurin-based cell viability potency assay reliably and reproducibly measured a dose-response of NK-EVs' cytotoxic activity against both cancer models. The assay showed precision with 5% and 20% variation for intra-run and inter-run variability. The assay signal showed specificity and selectivity of NK-EVs against cancer target cells, as evidenced by the diminished viability of cancer cells following a 5-hour treatment with NK-EVs, without any detectable interference or background. The linearity analysis of target cancer cells revealed strong linearity for densities of 5000 K562 and 1000 MDA-MB-231 cells per test with a consistent range. Importantly, NK-EVs' dose-response for cytotoxicity showed a strong correlation (|ρ| ∼ 0.8) with the levels of known cytotoxic factors associated with the NK-EVs' corona (FasL, GNLY, GzmB, PFN and IFN-γ), thereby validating the accuracy of the assay. The assay also distinguished cytotoxicity changes in degraded NK-EVs, indicating the ability of the assay to detect the potential loss of sample integrity. Compared to other commonly reported bioassays (i.e., flow cytometry, cell counting, lactate dehydrogenase release assay, DNA-binding reporter assay and confluence assay), our results support this highly sensitive resazurin-based viability potency assay as a high-throughput and quantitative method for assessing NK-EVs' cytotoxicity against both suspension and adherent cancer models for evaluating NK-EVs' biotherapeutics.

Isolation and Phenotypic Characterization of Tumor-Infiltrating NK Cells in Skin Carcinoma

In oncological research, the function of tumor-infiltrating natural killer (NK) cells in skin carcinoma presents a viable avenue for novel therapeutic methods. NK cells are essential to the body's defense against malignancies, including skin cancer, and are especially important in more sophisticated cancer immunotherapies such as vaccinations containing dendritic cells. The deadliest type of skin cancer, malignant melanoma, still has a poor prognosis even with advancements in early-stage therapies, which emphasizes the need for novel therapeutic strategies. NK cells from human melanoma metastases were subjected to single-cell RNA-seq analysis, which demonstrated notable variations in the transcriptional programs of tumor-infiltrating and circulating NK cells. Different transcriptional states are displayed by NK cells that have invaded tumors, indicating that they are functionally specialized in areas like chemokine production and cytotoxicity. These results emphasize the functions of NK cells in recruiting other significant immune cell types, such as cross-presenting dendritic cells, and in direct cytotoxicity against malignant cells. Investigating NK cells that infiltrate tumors in skin carcinomas presents a viable approach to comprehending and may be modifying the immune environment surrounding these cancers. It is essential to comprehend the distinct characteristics and roles of NK cells inside the tumor microenvironment in order to create more potent immunotherapeutic approaches to treat skin cancer. In order to perhaps open the door for new directions in cancer immunotherapy, the project intends to establish a thorough technique for the isolation and thorough phenotypic characterization of tumor-infiltrating NK cells in skin carcinoma.

Outcomes Following GD2-Directed Postconsolidation Therapy for Neuroblastoma After Cessation of Random Assignment on ANBL0032: A Report From the Children's Oncology Group

PURPOSE

Postconsolidation immunotherapy including dinutuximab, granulocyte-macrophage colony-stimulating factor, and interleukin-2 improved outcomes for patients with high-risk neuroblastoma enrolled on the randomized portion of Children's Oncology Group study ANBL0032. After random assignment ended, all patients were assigned to immunotherapy. Survival and toxicities were assessed.

PATIENTS AND METHODS

Patients with a pre-autologous stem cell transplant (ASCT) response (excluding bone marrow) of partial response or better were eligible. Demographics, stage, tumor biology, pre-ASCT response, and adverse events were summarized using descriptive statistics. Event-free survival (EFS) and overall survival (OS) from time of enrollment (up to day +200 from last ASCT) were evaluated.

RESULTS

From 2009 to 2015, 1,183 patients were treated. Five-year EFS and OS for the entire cohort were 61.1 ± 1.9% and 71.9 ± 1.7%, respectively. For patients ≥ 18 months old at diagnosis with International Neuroblastoma Staging System stage 4 disease (n = 662) 5-year EFS and OS were 57.0 ± 2.4% and 70.9 ± 2.2%, respectively. EFS was superior for patients with complete response/very good partial response pre-ASCT compared with those with PR (5-year EFS: 64.2 ± 2.2% v 55.4 ± 3.2%, P = .0133); however, OS was not significantly different. Allergic reactions, capillary leak, fever, and hypotension were more frequent during interleukin-2-containing cycles than granulocyte-macrophage colony-stimulating factor-containing cycles (P < .0001). EFS was superior in patients with higher peak dinutuximab levels during cycle 1 (P = .034) and those with a high affinity FCGR3A genotype (P = .0418). Human antichimeric antibody status did not correlate with survival.

CONCLUSION

Analysis of a cohort assigned to immunotherapy after cessation of random assignment on ANBL0032 confirmed previously described survival and toxicity outcomes. EFS was highest among patients with end-induction complete response/very good partial response. Among patients with available data, higher dinutuximab levels and FCGR3A genotype were associated with superior EFS. These may be predictive biomarkers for dinutuximab therapy.

SIRT2 promotes murine melanoma progression through natural killer cell inhibition

SIRT2, an NAD+-dependent histone deacetylase, has been shown to play a pivotal role in various physiological processes, however, its role in cancer is currently controversial. In recent years, SIRT2 has been described as both a tumor suppressor and oncogene with divergent expression and function in various malignancies. Using murine allograft melanoma models, our results suggest increased systemic expression of SIRT2 promotes tumor progression. In this study, SIRT2-overexpressing mice exhibited enhanced tumor growth and larger tumor volumes compared to their wild-type littermates. Mechanistically, systemic overexpression of SIRT2 reduces the number of tumor-infiltrating natural killer (NK) cells and suppresses NK cell function and proliferation within the tumor microenvironment (TME). Furthermore, despite the enhancing effect of NK cell depletion on tumor volume and growth rate in wild-type littermate mice, this effect was diminished in SIRT2-overexpressing mice. Lastly, pharmacological inhibition of SIRT2 increases NK cell tumor infiltration and suppresses allograft melanoma tumor growth. The findings of this study identify a dynamic functional interaction between systemic SIRT2 and NK cell activity, which controls melanoma tumor progression. Given the recent renewed interest in NK-cell-mediated immunotherapy response, SIRT2 could present a new opportunity to mediate immunotherapy response and resistance.

CD56dim CD16- Natural Killer Cell Profiling in Melanoma Patients Receiving a Cancer Vaccine and Interferon-α

Natural killer (NK) cells are innate cytotoxic and immunoregulatory lymphocytes that have a central role in anti-tumor immunity and play a critical role in mediating cellular immunity in advanced cancer immunotherapies, such as dendritic cell (DC) vaccines. Our group recently tested a novel recombinant adenovirus-transduced autologous DC-based vaccine that simultaneously induces T cell responses against three melanoma-associated antigens for advanced melanoma patients. Here, we examine the impact of this vaccine as well as the subsequent systemic delivery of high-dose interferon-α2b (HDI) on the circulatory NK cell profile in melanoma patients. At baseline, patient NK cells, particularly those isolated from high-risk patients with no measurable disease, showed altered distribution of CD56^dim CD16⁺ and CD56^dim CD16⁻ NK cell subsets, as well as elevated serum levels of immune suppressive MICA, TN5E/CD73 and tactile/CD96, and perforin. Surprisingly, patient NK cells displayed a higher level of activation than those from healthy donors as measured by elevated CD69, NKp44 and CCR7 levels, and enhanced K562 killing. Elevated cytolytic ability strongly correlated with increased representation of CD56^dim CD16⁺ NK cells and amplified CD69 expression on CD56^dim CD16⁺ NK cells. While intradermal DC immunizations did not significantly impact circulatory NK cell activation and distribution profiles, subsequent HDI injections enhanced CD56^bright CD16⁻ NK cell numbers when compared to patients that did not receive HDI. Phenotypic analysis of tumor-infiltrating NK cells showed that CD56^dim CD16⁻ NK cells are the dominant subset in melanoma tumors. NanoString transcriptomic analysis of melanomas resected at baseline indicated that there was a trend of increased CD56^dim NK cell gene signature expression in patients with better clinical response. These data indicate that melanoma patient blood NK cells display elevated activation levels, that intra-dermal DC immunizations did not effectively promote systemic NK cell responses, that systemic HDI administration can modulate NK cell subset distributions and suggest that CD56^dim CD16⁻ NK cells are a unique non-cytolytic subset in melanoma patients that may associate with better patient outcome.

Hemacytotoxicity and natural killer lytic index: New parameters to evaluate natural killer cell immunity for clinical use in cancer

Cytotoxicity assays with patient peripheral blood mononuclear cell (PBMC)-derived natural killer (NK) cells are useful in evaluating the innate immunity of patients with cancer. However, the size of the NK cell population in PBMC preparations may have significant effects on the assay outcome. Therefore, the present study examined the effect of NK cell frequency in a cytotoxicity system to investigate NK cell immunity in post-surgical colorectal cancer patients. For this, hemacytotoxicity was assessed using PBMC preparations, and lymphocyte subset populations were analyzed in samples obtained from 47 patients and 45 healthy volunteers. In addition, a new theoretical parameter, the 'NK lytic index', was termed to represent the per-cell cytotoxicity and compensate for the NK cell frequency effect during PBMC preparations. Notably, the patterns of hemacytotoxicity and NK lytic index did not coincide in follow-up studies with consecutive patients following surgical intervention. In addition, it was determined that NK cell NKG2D expression influences NK lytic index, but not hemacytotoxicity. Transforming growth factor (TGF)-β-bound lymphocytes influenced hemacytotoxicity and NK lytic index. These findings indicate that total cell activity (hemacytotoxicity) is not a sum of per-cell activities (NK lytic indexes), suggesting that clinicians should employ NK lytic index in addition to hemacytotoxicity in order to precisely determine how to enhance NK cell immunity in patients with cancer, either focusing on recovering the number of NK cells or boosting NK cell activity in single cell levels, or both.

An improved method to quantify human NK cell-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) per IgG FcR-positive NK cell without purification of NK cells

Natural killer (NK) lymphocyte ADCC supports anti-viral protection and monoclonal antibody (mAb) anti-tumor therapies. To predict in vivo ADCC therapeutic responses of different individuals, measurement of both ADCC cellular lytic capacity and their NK cellular receptor recognition of antibodies on 'target' cells are needed, using clinically available amounts of blood. Twenty ml of blood provides sufficient peripheral blood mononuclear cells (PBMCs) for the new assay for lytic capacity described here and for an antibody EC₅₀ assay for Fc-receptor recognition. For the lytic capacity assay, we employed flow cytometry to quantify the CD16A IgG Fc-receptor positive NK effector cells from PBMCs to avoid loss of NKs during isolation. Targets were ⁵¹Cr-labeled Daudi B cells pretreated with excess obinutuzumab type 2 anti-CD20 mAb and washed; remaining free mAb was insufficient to convert B cells in the PBMCs into 'targets'. We calculated: the percentage Daudis killed at a 1:1 ratio of CD16A-positive NK cells to Daudis (CX1:1); lytic slopes; and ADCC₅₀ lytic units. Among 27 donors, we detected wide ranges in CX1:1 (16-73% targets killed) and in lytic slopes. Slope variations prevented application of lytic units. We recommend CX1:1 to compare individuals' ADCC capacity. CX1:1 was similar for purified NK cells vs. PBMCs and independent of CD16A V & F genotypes and antibody EC₅₀s. With high mAb bound onto targets and the high affinity of obinutuzumab Fc for CD16A, CX1:1 measurements discern ADCC lytic capacity rather than antibody recognition. This assay allows ADCC to be quantified without NK cell isolation and avoids distortion associated with lytic units.

Tumor-Derived α-Fetoprotein Directly Drives Human Natural Killer-Cell Activation and Subsequent Cell Death

Hepatocellular carcinoma (HCC) patients with reduced natural killer (NK)-cell numbers and function have been shown to have a poor disease outcome. Mechanisms underlying NK-cell deficiency and dysfunction in HCC patients remain largely unresolved. α-Fetoprotein (AFP) is an oncofetal antigen produced by HCC. Previous studies demonstrated that tumor-derived AFP (tAFP) can indirectly impair NK-cell activity by suppressing dendritic cell function. However, a direct tAFP effect on NK cells remains unexplored. The purpose of this study was to examine the ability of cord blood-derived AFP (nAFP) and that of tAFP to directly modulate human NK-cell activity and longevity in vitro Short-term exposure to tAFP and, especially, nAFP proteins induced a unique proinflammatory, IL2-hyperresponsive phenotype in NK cells as measured by IL1β, IL6, and TNF secretion, CD69 upregulation, and enhanced tumor cell killing. In contrast, extended coculture with tAFP, but not nAFP, negatively affected long-term NK-cell viability. NK-cell activation was directly mediated by the AFP protein itself, whereas their viability was affected by hydrophilic components within the low molecular mass cargo that copurified with tAFP. Identification of the distinct impact of circulating tAFP on NK-cell function and viability may be crucial to developing a strategy to ameliorate HCC patient NK-cell functional deficits. Cancer Immunol Res; 5(6); 493-502. ©2017 AACR.

Description of the immune microenvironment of chondrosarcoma and contribution to progression

Chondrosarcoma (CHS) is a rare bone malignancy characterized by its resistance to conventional systemic and radiation therapies. Whether immunotherapy targeting immune checkpoints may be active in these tumors remains unknown. To explore the role of the immune system in this tumor, we analyzed the immune environment of chondrosarcomas both in human sample, and in a syngeneic rat model, and tested the contribution of T lymphocytes and macrophages in chondrosarcoma progression. Immunohistochemical stainings were performed on human chondrosarcoma samples and on Swarm rat chondrosarcoma (SRC) model. Selective immunodepletion assays were performed in SRC to evaluate immune population's involvement in tumor progression. In human and rat chondrosarcoma, immune infiltrates composed of lymphocytes and macrophages were identified in the peritumoral area. Immune infiltrates composition was found correlated with tumors characteristics and evolution (grade, invasiveness and size). In SRC, selective depletion of T lymphocytes resulted in an accelerated growth rates, whereas depletion of CD163⁺ macrophages slowed down tumor progression. Splenocytes isolated from CHS-bearing SRC showed a specific cytotoxicity directed against chondrosarcoma cells (27%), which significantly decreased in CD3-depleted SRC (11%). The immune environment contributes to CHS progression in both human and animal models, suggesting that immunomodulatory approaches could be tested in bone chondrosarcoma.

Age-related alteration of expression and function of TLRs and NK activity in oral candidiasis

OBJECTIVE

Roles of aging or immune responses mediated by Toll-like receptors and natural killer cell in the onset or progression of human candidiasis remain unclear. This study was designed to elucidate the roles using peripheral blood mononuclear cells from healthy donors and patients with oral candidiasis.

SUBJECTS AND METHODS

Subjects tested were healthy volunteers and patients who visited Dental Clinical Division of Hokkaido University Hospital. The patients with oral candidiasis included 39 individuals (25-89 years of age) with major complaints on pain in oral mucosa and/or dysgeusia. Healthy volunteers include students (25-35 years of age) and teaching staffs (50-65 years of age) of Hokkaido University Graduate School of Dental Medicine.

RESULTS

Functions of Toll-like receptors 2 and 4 were downregulated significantly and the natural killer activity was slightly, but not significantly downregulated in aged healthy volunteers compared with healthy young volunteers. Functions of Toll-like receptors 2 and 4 and the natural killer activity were significantly downregulated in patients with oral candidiasis compared with healthy volunteers.

CONCLUSION

Downregulation of functions of Toll-like receptors 2 and 4 as well as natural killer activity is suggested to be associated with the onset or progression of oral candidiasis in human.

Lack of functional TSLP receptors mitigates Th2 polarization and the establishment and growth of 4T1 primary breast tumours but has different effects on tumour quantities in the lung and brain

The 4T1 mammary carcinoma cell line produces TSLP. We had hypothesized that TSLP promotes the development of a permissive environment for the growth and metastasis of primary tumour and that this is associated with a Th2-polarized antitumour immune response. We found that, in Tslpr(-/-) mice, the mean tumour diameters were smaller from days 27 to 40, and relatively fewer tumour cells were present in the lung, compared with wild-type mice. Polarization of the Th2 cytokine profile was also diminished in Tslpr(-/-) mice. These findings confirmed those reported previously by others. Here, we further show that primary tumours are established less often in Tslpr(-/-) mice and that, unexpectedly, the relative number of tumour cells in the brain is greater in Tslpr(-/-) mice compared with wild-type mice. Findings from our cytotoxicity assays show that 4T1-directed lysis is undetectable in both WT and Tslpr(-/-) mice, ruling out the possibility that altered cytotoxic responses in Tslpr(-/-) mice are responsible for the differences we observed. In a human tissue microarray, positive staining for TSLP was seen in tumour cells from breast cancer tissue, but it was also seen in normal glandular epithelial cells from normal breast tissue, which has not been shown before. Thus, our findings provide new insight into the effects of TSLP in metastatic breast cancer.

Immunostimulating effect of a well-known Thai folkloric remedy in breast cancer patients

The study aimed to evaluate immune-stimulating effects of a well-known Thai folkloric remedy when used for adjuvant therapy with conventional chemotherapeutics for treatment of breast cancer. Immunostimulating influence of the remedy (215 mg/kg body weight per day) on NK cell activity and TNF-α release from the monocytes/macrophages were investigated in a total of 15 healthy women and 13 female patients with breast cancer (Group 1). The effect of breast tumor surgery on NK cell activity was further investigated in 18 female patients with breast cancer (Group 2). NK cell cytotoxic activity was determined by chromium release cytotoxic assay using K562, an erythroleukemic cell line. TNF-α release from monocytes/macrophages separated from blood samples was determined through a biological assay using actinomycin D-treated L929 mouse fibroblast cells in the presence and absence of LPS. Baseline NK cell activity of the monocytes/macrophages separated from Group 2 patients expressed as %cytotoxicity was significantly lower than in the healthy subjects at E:T ratios of 100:1 and 25:1. In healthy subjects, there was no change in NK cell cytotoxic activity (%cytotoxicity or LU) following 1 and 2 weeks of treatment with the remedy compared with the baseline at various E:T ratios but the binding activity (%binding) was significantly increased after 2 weeks of treatment. The addition of one or two conventional chemotherapeutic regimens did not significantly reduce the NK cytotoxic activity but did affect release of TNF-α in both unstimulated and LPS-stimulated samples. Surgery produced a significant suppressive effect on NK cell activity. The use of the remedy as an adjunct therapy may improve therapeutic efficacy and safety profiles of conventional chemotherapeutic regimens through stimulation of the immune system in cancer patients.

Beta2-adrenoceptor stimulation suppresses TLR9-dependent IFNA1 secretion in human peripheral blood mononuclear cells

Introduction

IFNA1 (interferon alpha) is a key cytokine regulating the activity of numerous immune cells. Plasmacytoid dendritic cells (pDCs) as natural interferon-producing cells play critical roles as sensors of pathogens and link innate to adaptive immunity. CpG motifs within DNA sequences activating toll-like receptor 9 (TLR9) are the main stimuli eliciting IFNA1 secretion from pDCs. Adrenergic substances are capable of differentially modulating the response from various immune cells. Hence, the aim of this study was to examine how adrenoceptor stimulation influences TLR9-induced IFNA1 secretion from human pDCs.

Methods

PBMCs generated from human whole blood and pDCs enriched from buffy coats were stimulated with LPS and CpG-ODN 2336 in the presence or absence of epinephrine and different adrenoceptor antagonists. Secretion of TNF and IFNA1 was measured by ELISA. Flow cytometry was used to determine efficacy of pDC enrichment and adrenoceptor expression of PBMC subsets. The influence of modified IFNA1 secretion on NK cell activity was evaluated using a colorimetric tumor cell lysis assay.

Results

TLR9-induced IFNA1 secretion as well as TLR4-induced TNF secretion from PBMCs was dose-dependently attenuated by coincubation with epinephrine. Combination with different specific adrenoceptor antagonists revealed that this effect was mediated by the adrenoceptor β₂ (ADRB2). Since flow cytometric analysis could exclude the presence of ADRB2 on pDCs, highly enriched pDCs lacked any visible impact of adrenoceptor stimulation on TLR9-induced IFNA1 release. Combination of pDCs with PBMCs restored the effect, even when they were separated by a permeable membrane. Suppression of TLR9-mediated IFNA1 secretion from PBMCs by adrenoceptor stimulation reduced the lytic activity of NK cells on K562 tumor cells.

Conclusion

We provide insights into the underlying mechanisms of the interrelation between immune responses and pharmacological agents widely used in clinical practice. Our results have implications for the future treatment of human patients, in which the endogenous immune response plays a pivotal role, such as during viral infections, inflammatory diseases and cancers.

MGN-3 arabinoxylan rice bran modulates innate immunity in multiple myeloma patients

Dendritic cells (DCs) and natural killer (NK) cells are central components of innate immunity for controlling tumor growth. The therapeutic effects of certain anti-myeloma drugs are partially mediated by targeting the innate immune response. In addition, novel types of natural compounds have been developed that efficiently modulate the activity of both the cellular and humoral compartments of immunity. MGN-3 is known as an activator of natural killer cells, inducer of apoptosis and cytokine production, and modulator of dendritic cell maturation and differentiation in vitro. We have performed a randomized, placebo-controlled study to examine the effects of MGN-3 on innate immune system parameters in 48 multiple myeloma patients. We performed immunophenotypic analysis of peripheral blood samples, determined NK cell activity, and assessed the cytokine profiles of plasma before and during 3 months of treatment. The results demonstrate a clear increase in NK activity in MGN-3-treated patients compared to the placebo group, an increased level of myeloid DCs in peripheral blood, and augmented concentrations of T helper cell type 1-related cytokines. The present study suggests that MGN-3 may represent an immunologically relevant product for activating innate immunity in multiple myeloma patients and warrants further testing to demonstrate clinical efficacy.

Amino acid and vitamin supplementation improved health conditions in elderly participants

The purpose of this study was to investigate the effects of supplementation with amino acids and vitamins on health conditions in unhealthy older people. One bedridden inpatient group (n = 10; mean age, 79.8 ± 8.5 y) and one outpatient group (n = 9; mean age, 72.9 ± 12.2 y) participated in this study. A mixture supplementation with amino acids containing arginine (500 mg/day), glutamine (600 mg/day), and leucine (1200 mg/day), and 11 kinds of vitamins was daily administrated for 8 weeks. In both groups, general blood biomarkers such as white blood cell count, natural killer cell activity, and C-reactive protein levels were measured. All measurements were taken before (baseline), at 4 weeks (mid-point), and after each trial (post-point). At mid-point, natural killer cell activity in the outpatient group increased significantly compared to baseline. At post-point, natural killer cell activity in the outpatient and inpatient groups increased significantly compared to baseline. The other blood biomarkers did not show any significant change throughout the trial. This pilot study suggested that a mixture of arginine, glutamine, leucine, and vitamins is useful to support innate immunity in unhealthy older people, even if their diseases, symptoms, and prescribed medicines are different.

Ex vivo measurement of the cytotoxic capacity of human primary antigen-specific CD8 T cells

The major function of CD8 T cells is to kill specifically target cells. Moreover in certain incurable diseases, antigen-specific human CD8 T cells are impaired, and assessment of their cytolytic activity could bring insights into their physiopathological role and ways to restore immune dysfunctions for immunotherapeutic purposes. Despite this, T cell cytolytic function has been seldom analyzed thoroughly in humans, due to the lack of approaches well suited for ex vivo assessment of T cell cytotoxicity. Current techniques require prior in vitro expansion of antigen-specific CD8 T cell populations and the use of immortalized cells as targets to measure the cell-mediated killing. Furthermore, bulk cytotoxic activity is frequently measured using percentage of specific lysis calculations that do not quantify actual target cell death and effector numbers at the single cell level. Here we established a new flow cytometry-based assay that allows accurate single-cell analysis of cytotoxic capacity of primary antigen-specific CD8 T cells generated in vivo in humans after antigenic exposure without in vitro amplification that can be used for specificities restricted by different HLAs as target cells are autologous cells. We show that this assay is robust, highly sensitive irrespective of the frequency of antigen-specific CD8 T cells, and allows accurate calculation of the index of cytotoxic capacity in lytic units. This new assay provides a sensitive method to measure the intrinsic cytotoxic activity of antigen-specific CD8 T cells directly ex vivo on human primary cells.

Association of general fatigue with cellular immune indicators among healthy white-collar employees

OBJECTIVE

Although fatigue is a common complaint in the working population, underlying immunological mechanisms are not well understood. This study investigated the association of general fatigue with cellular immune indicators.

METHODS

A total of 148 healthy white-collar employees (70% men) underwent a blood draw for the measurement of natural killer (NK), B, and T cell counts as well as NK cell cytotoxicity (NKCC) and completed two different fatigue scales, that is, Profile of Mood State (POMS) and Maastricht Questionnaire (MQ).

RESULTS

Multiple linear regression analyses revealed that POMS fatigue score was significantly associated with decreases of NK cells (β = -.407) and NKCC (β = -.215), whereas MQ fatigue score was significantly associated with reduced NK cells (β = -.290) but not with NKCC (β = -.127).

CONCLUSION

The results suggest that general fatigue may be related to impaired NK cell competency among healthy employees.

Effects of fatigue on immune function in nurses performing shift work

OBJECTIVES

We investigated the effects of fatigue on NK cell function and lymphocyte subpopulations in nurses performing shift work using a longitudinal design.

METHODS

Fifty-seven female nurses engaged in shift work at a hospital in Japan were selected for our study cohort. The hospital used a counterclockwise rotating three-shift system. Night shifts followed day shifts after a seven-hour interval. Immune parameters measured at the beginning of the day shift through to the end of the night shift were compared between two groups stratified by their level of fatigue. Statistical differences were evaluated after adjusting for baseline immune values and other demographic features.

RESULTS

Subjective feelings of fatigue increased progressively from the beginning of day shifts to the end of night shifts. From the beginning of day shifts to the end of night shifts, NK cell activity and CD16(+)CD56(+) lymphocytes decreased, while CD3(+) and CD4(+) lymphocytes increased. The group with the greater increase in fatigue showed a larger decrease in NK cell activity and a larger increase in CD4(+)lymphocytes when compared with the group reporting less fatigue. These findings did not change after adjusting for demographic factors and sleep hours.

CONCLUSION

Our data suggest that shift work has deleterious effects on NK cell function and that the effects depend on the degree of fatigue. Proper management of shift work may lessen fatigue in workers and also ameliorate many health problems experienced by shift workers.

Psychological distress, depressive symptoms, and cellular immunity among healthy individuals: a 1-year prospective study

Cross-sectional and case-control studies have reported that psychological distress and depression are associated with reduced cellular immune competence but the directionality of the relationship remains uncertain. This study investigated whether levels of psychological distress and depressive symptoms are related to subsequent changes in counts of lymphocyte subsets (natural killer (NK), B, and T cell) and/or whether changes of immune markers predict psychological distress/depressive symptoms in a 1-year prospective study design. A total of 105 healthy employees (67 men and 38 women), aged 23-59 (mean 40) years with an average of 15years of education, underwent a blood draw for the measurement of circulating immune cells and completed the Japanese version of the 28-item General Health Questionnaire (GHQ-28) and the Center for Epidemiologic Studies Depression Scale (CES-D) in April 2002 (time 1) and 2003 (time 2). Hierarchical multiple linear regression analyses revealed that GHQ-28 and CES-D scores at time 1 were significantly (p<.05) and inversely associated with NK cells at time 2 controlling for potential confounders including time 1 NK cells (β=-.221 and -.177, respectively). In contrast, NK cells and NK cell cytotoxicity at time 1 did not predict GHQ-28 or CES-D score at time 2 controlling for GHQ-28/CES-D score at time 1. GHQ-28 and CES-D scores were not related to T or B cells at times 1 and 2. The present findings indicate that psychological distress and depressive symptoms may precede and predict suppression of NK cell immunity while NK cells did not lead to subsequent psychological distress and depressive symptoms, suggesting an absence of the bi-directional relationships.

Job satisfaction is associated with elevated natural killer cell immunity among healthy white-collar employees

Although the association of job satisfaction with health has been well documented, little is known about the biological mechanisms underlying this relationship. This study investigates the association of job satisfaction with cell-mediated immunity among Japanese white-collar daytime workers. A total of 306 healthy full-time employees (141 women and 165 men), aged 22-69 (mean 36) years, provided a blood sample for the measurement of circulating immune (natural killer (NK), B, and total T) cells and NK cell cytotoxicity (NKCC) and completed a questionnaire survey during April to June 2002. Job satisfaction was measured by a 4-item scale from the Japanese version of the generic job stress questionnaire with higher scores indicating greater satisfaction. Analyses were done separately for women and men using a hierarchical multiple linear regression model controlling for multiple confounders. The results revealed that greater job satisfaction was positively correlated with NKCC (β = .207; p = .029) and the number of NK (CD3(-)CD56(+)) cells (β = .261; p = .008) in women. In men, job satisfaction was marginally correlated with NKCC (β = .165; p = .050) but was not correlated with the number of NK (CD3(-)CD56(+)) cells (β = .142; p = .107). Job satisfaction did not correlate with numbers of T (CD3(+)CD56(-)) and B (CD19(+)) cells in both women and men. Our findings suggest an independent association between job satisfaction and NK cells but the association seems to be stronger in women than in men. Although the results provide a support for the biological plausibility of the job satisfaction-health relationship, additional research is required to determine whether greater job satisfaction contributes to recovery/maintenance of NK cell immunity and host defense over time.

Opioid-like activity of naltrexone on natural killer cell cytolytic activity and cytokine production in splenocytes: effects of alcohol

Chronic alcohol consumption has been shown to decrease the activity of natural killer (NK) cell cytolytic function and the production of various cytokines from the spleen. We have recently shown that naltrexone, an opiate receptor antagonist, when administered for a period of 2 weeks suppresses micro-opiate receptor binding but increases partial differential-opiate receptor activity in rat splenocytes. However, the effects of long-term naltrexone treatment on alcohol-induced alteration of NK cell cytolytic activity and cytokines production in splenocytes have not been determined. Male rats were pair-fed an isocaloric liquid diet or fed an ethanol-containing liquid diet for a period of 3 weeks. These rats were additionally treated after a week with a subcutaneous implant of either a naltrexone pellet or placebo pellet for 2 weeks. Splenocytes were isolated and used for determination of various cytokines interleukin (IL)-2, IL-4, and IL-6, and interferon-gamma (IFN-gamma) using enzyme-linked immunosorbent assay (ELISA), and the basal and IL-2-, IL-12-, or IL-18-induced NK cytolytic activity was measured using a standard 4-h (51)Cr release assay against YAC-1 lymphoma target cells. Ethanol consumption resulted in a reduction of the production of IL-2, IL-4, and IL-6 as well as the basal and cytokine-activated NK cell cytolytic activity and IFN-gamma production in splenocytes. Naltrexone administration increased the production of IL-2, IL-4, and IL-6 and the basal and cytokine-activated NK cell cytolytic activity and IFN-gamma production in the splenocytes of pair-fed and alcohol-fed rats. These results indicated that naltrexone treatment increases NK cell cytolytic activity and cytokine production in the spleen in vivo. Furthermore, these results identify the potential of the use of naltrexone in the treatment of immune deficiency in alcoholic and non-alcoholic patients.

Cystine and theanine supplementation restores high-intensity resistance exercise-induced attenuation of natural killer cell activity in well-trained men

We investigated the effects of supplementation with cystine, a dipeptide of cysteine, and theanine (CT), a precursor of glutamate, on immune variables during high-intensity resistance exercise. Cysteine and glutamate are involved in the formation of glutathione, which modulates the activity of natural killer (NK) cells. In this double-blinded clinical trial, 15 well-trained men (aged 22.8 +/- 4.0 years) were divided into 2 groups: placebo (n = 7) and CT (n = 8). The placebo group was administered a powder containing cellulose (950 mg) and glutamate (30 mg), whereas the CT group was administered a powder containing cystine (700 mg) and theanine (280 mg), once daily for 2 weeks. The subjects trained according to their normal schedule (3 times per week) in the first week and trained at double the frequency (6 times per week) in the second week. Concentrations of immunoglobulin (Ig)M, interleukin (IL)-6, IL-8, and salivary IgA and the leukocyte count did not change significantly in either group. There was a significant decrease (p < or = 0.05) in the NK cell activity (NKCA) in the placebo group after the second week compared with that in the CT group (placebo: 69.2 +/- 16.1% vs. CT: 101.7 +/- 38.7%). Phytohemagglutinin-induced lymphocyte blastoid transformation did not change significantly in either group. These results suggest that NKCA is not affected in a normal training schedule with or without CT supplementation. However, high-intensity and high-frequency resistance exercises cause attenuation of NKCA, which CT supplementation appears to restore. Therefore, in practical application, CT supplementation would be useful for athletes to restore the attenuation of NKCA during high-intensity and high-frequency training.

Virally infected and matured human dendritic cells activate natural killer cells via cooperative activity of plasma membrane-bound TNF and IL-15

Recombinant adenovirus-engineered dendritic cells (Ad.DCs) are potent immunologic adjuvants of antiviral and anticancer vaccines. The effectiveness of Ad.DC-based vaccines may depend on the ability of Ad.DCs to crosstalk with natural killer (NK) cells and to activate, polarize, and bridge innate and adaptive immunity. We investigated, for the first time, whether and how human Ad.DCs activate NK cells, and compared the Ad.DC function with that of immature DCs and matured DCs (mDCs). We found that adenovirus transduction and lipopolysaccharide/interferon-gamma-induced maturation increased expression of transmembrane tumor necrosis factor (TNF) and trans-presented (trans) interleukin-15 (IL-15) on DCs, leading to enhanced NK cell activation without enhancing DC susceptibility to NK cell-mediated killing. This crosstalk enhanced NK cell CD69 expression, interferon-gamma secretion, proliferation, and antitumor activities, with Ad.DCs being significantly more effective than immature DCs, but less effective than mDCs. The Ad.DC and mDC crosstalk with NK cells was largely prevented by physical separation of DCs and NK cells, and neutralization of total TNF and IL-15, but not by selective sequestration of soluble TNF. These findings demonstrate that both Ad.DCs and mDCs can efficiently promote innate immune functions by activation of NK cells through the cooperative activities of tmTNF and trans-IL-15 mediated by cell-to-cell contact.

Natural Killer Cell Activity Decreases in Workers Occupationally Exposed to Extremely Low Frequency Magnetic Fields Exceeding 1 μt

In a preliminary study a reduction in Natural Killer (NK) cell activity in peripheral blood lymphocytes (PBL) was observed in a group of workers exposed to levels of Extremely Low Frequency-Magnetic Fields (ELF-MF) exceeding 1 μT. This study was performed to confirm the results. In 121 workers engaged in various occupational activities, individual ELF-MF exposure was monitored for 2 work shifts. Exposure levels were calculated as Time-Weighted Average (TWA). Subjects were classified as Low exposure (TWA ≤ 0.2 μT), Medium exposure (TWA 0.21–0.99 μT), or Higher exposure (TWA ≥1 μT). In higher exposure workers NK activity proved significantly reduced compared to low exposure, (p<0.01). In medium exposure a reduction was also observed, but the difference was not significant. Multivariate analysis also confirmed the relation between exposure and NK activity. It has been suggested that ELF might affect tumour progression by inducing changes in the immune system: due to the role played by NK activity in host defence against cancer, the interference with the NK cell activity observed in this study is in agreement with this hypothesis. Furthermore, an increased risk for some neurodegenerative disorders has been reported in some epidemiological studies in ELF-MF-exposed workers: changes in NK function were also described in these diseases. Our results, showing the effect on NK activity of exposure exceeding 1 μT, suggest a possible mechanism for ELF-MF effects. This could open new horizons regarding the adverse long-term effects of these fields.

Beta-endorphin neuronal cell transplant reduces corticotropin releasing hormone hyperresponse to lipopolysaccharide and eliminates natural killer cell functional deficiencies in fetal alcohol exposed rats

BACKGROUND

Natural killer (NK) cell dysfunction is associated with hyperresponse of corticotropin releasing hormone (CRH) to immune challenge and with a loss of beta-endorphin (BEP) neurons in fetal alcohol exposed animals. Recently, we established a method to differentiate neural stem cells into BEP neurons using cyclic adenosine monophosphate (cAMP)-elevating agents in cultures. Hence, we determined whether in vitro differentiated BEP neurons could be used for reversing the compromised stress response and immune function in fetal alcohol exposed rats.

METHODS

To determine the effect of BEP neuron transplants on NK cell function, we implanted in vitro differentiated BEP neurons into the paraventricular nucleus of pubertal and adult male rats exposed to ethanol or control in utero. The functionality of transplanted BEP neurons was determined by measuring proopiomelanocortin (POMC) gene expression in these cells and their effects on CRH gene expression under basal and after lipopolysaccaride (LPS) challenge. In addition, the effectiveness of BEP neurons in activating NK cell functions is determined by measuring NK cell cytolytic activity and interferon-gamma (IFN-gamma) production in the spleen and in the peripheral blood mononuclear cell (PBMC) following cell transplantation.

RESULTS

We showed here that when these in vitro differentiated BEP neurons were transplanted into the hypothalamus, they maintain biological functions by producing POMC and reducing the CRH neuronal response to the LPS challenge. BEP neuronal transplants significantly increased NK cell cytolytic activity in the spleen and in the PBMC and increased plasma levels of IFN-gamma in control and fetal alcohol exposed rats.

CONCLUSIONS

These data further establish the BEP neuronal regulatory role in the control of CRH and NK cell cytolytic function and identify a possible novel therapy to treat stress hyperresponse and immune deficiency in fetal alcohol exposed subjects.

Comparison of the safety and immunogenicity of ACAM1000, ACAM2000 and Dryvax in healthy vaccinia-naive adults

Currently, more than half of the world's population has no immunity against smallpox variola major virus. This phase I double-blind, randomized trial was conducted to compare the safety and immunogenicity of two clonally derived, cell-culture manufactured vaccinia strains, ACAM1000 and ACAM2000, to the parent vaccine, Dryvax. Thirty vaccinia-naïve subjects were enrolled into each of three groups and vaccines were administered percutaneously using a bifurcated needle at a dose of 1.0x10(8)PFU/mL. All subjects had a primary skin reaction indicating a successful vaccination. The adverse events, 4-fold neutralizing antibody rise and T cell immune responses were similar between the groups.

Protective immunity against neu-positive carcinomas elicited by electroporation of plasmids encoding decreasing fragments of rat neu extracellular domain

We have shown that electroporation of plasmid carrying extracellular and transmembrane domains (EC-TM plasmid) encoded by the rat neu oncogene triggers a protective immune response toward rat p185(neu)-positive tumors in both wild-type BALB/c mice and cancer-prone rat neu-transgenic BALB-neuT mice. To identify the critical fragments that confer this protective immunity, mice were electroporated with plasmids encoding the TM domain associated with decreasing fragments of the EC domain and the antitumor protection afforded, the titer of antibody, and cytotoxic T lymphocyte (CTL) activity elicited to Neu protein were evaluated. Plasmids encoding EC fragments shortened by 70 (EC1-TM plasmid), 150 (EC2-TM), 230 (EC3-TM), 310 (EC4-TM), and 390 (EC5-TM) NH(2)-terminal residues afforded effective protection. Plasmids encoding shorter truncated proteins were ineffective. When the immunogenic protein was retained in the cytoplasm (EC1-TM, EC2-TM, and EC5-TM), only a CTL response was elicited, whereas when it was also expressed on the membrane (EC4-TM) both CTLs and antibodies were induced. EC4-TM encoding a truncated protein with an EC portion of only 344 amino acids conferred protection on both BALB/c and BALB-neuT mice comparable to that of EC-TM.

Palifermin mediates immunoregulatory effects in addition to its cytoprotective effects in mice with acute graft-versus-host disease

INTRODUCTION

Treating recipient mice with palifermin (recombinant human keratinocyte growth factor) prevents the development of acute, lethal, graft-versus-host disease (GVHD). This is due, at least in part, to the ability of palifermin to protect epithelial cells from injury. Using the C57BL/6-->(C57BL/6 x DBA/2)F(1)-hybrid model, we previously showed that the protective effect of palifermin was also associated with redirection of the cytokine profile from Th1 to Th2.

DISCUSSION

To study this immunoregulatory effect more directly, we induced acute GVH reactions in which we treated the donors rather than the recipients with palifermin. The recipient mice were protected from GVHD-associated morbidity, and their cytokine profile was predominantly Th2. The palifermin-treated donor mice alone showed a similar Th2 cytokine profile, and we observed elevated levels of thymic stromal lymphopoietin mRNA in the thymus. We further demonstrated that treating the donor mice with palifermin protects against GVHD-associated morbidity, even if the donors are deficient in Valpha14i natural killer T cells. Our findings clearly show that palifermin mediates immunoregulatory effects in addition to its cytoprotective effects and that both are likely to be involved in the mechanism through which palifermin provides protection from acute murine GVHD.

An occupational health study of emergency physicians in Japan: health assessment by immune variables (CD4, CD8, CD56, and NK cell activity) at the beginning of work

This study was conducted to evaluate the occupational health of Japanese physicians in emergency medicine. Subjects participating in this study were eighty-nine physicians working at 12 medical facilities (10 critical care emergency centers) in Japan. Participants were asked to complete a questionnaire of work conditions and to provide blood samples for immune variable measurements (CD4, CD8, CD56 and natural killer cell (NK cell) activity) before commencing their work. The data collected from seventy-four of 89 participating physicians were analyzed. The traditional work group comprised of 39 emergency physicians, who were significantly overworked compared to other two groups: the shift work group and the day work group. Among these three groups, no immune variable was significantly different except lymphocyte, number of CD4, and NK cell activity; and the NK cell activity of the shift work group was significantly lower than those of the traditional work group (p<0.01) and the day work group (p<0.01) in terms of Bonferroni's multiple comparison, probably due to circadian rhythm. It was indicated that NK cell activity was significantly lower in samples collected at night versus in the morning (OR=8.34, 95%CI: 1.95-35.6, p<0.01) through multiple logistic regression analyses. NK cell activity was significantly lower in individuals taking 0-3 days off per month, as compared to those taking 4 or more days off (OR=4.65, 95%CI: 1.27-17.0, p=0.02), according to multiple logistic regression analyses. Therefore, the low NK cell activity appears to have reflected the extent of fatigue arising from physicians' overwork. Overwork would have been a potential risk for the physicians' health, resulting in a lower quality of Japanese emergency medical services than that which could have been achieved otherwise. This study suggests that it would be better for the Japanese emergency physicians to take 4 or more days off per month for their health and the quality of their services.

Long-term exposure to gaseous formaldehyde promotes allergen-specific IgE-mediated immune responses in a murine model

It has long been questioned that whether exposure to formaldehyde in indoor environments may be a risk factor for developing allergen-specific IgE-mediated inflammatory responses, because there is limited clinical or experimental evidence that formaldehyde is involved in the cascade for IgE production. There is no known lower limit, below which there is no threat of serious allergic symptoms. The present study illustrates that the threshold limit of formaldehyde, 0.08 ppm (as defined by the World Health Organization), did not cause ovalbumin-specific IgE inflammatory immune responses, but higher than threshold concentrations of formaldehyde gas result in both enhanced allergen-specific IgE responses and NK (Natural Killer)-cell activity in peripheral blood cells in a murine model. Thus, formaldehyde gas may be involved in promoting allergic inflammatory effects in subjects primed with specific allergens by NK-cell activation. These results indicate that even threshold concentrations of formaldehyde gas may play a regulatory role for ‘systemic’ cell-mediated immune responses. The extensive use of adhesives for building materials has resulted in higher levels of indoor air pollutants. It is conceivable that increased time indoors may enhance pre-existing allergic symptoms by concomitant exposure to volatile organic compounds and formaldehyde. The affordable limit for formaldehyde might be much lower than currently established levels in indoor environments.

Gene-modified T cells for adoptive immunotherapy of renal cell cancer maintain transgene-specific immune functions in vivo

BACKGROUND

We have treated three patients with carboxy-anhydrase-IX (CAIX) positive metastatic renal cell cancer (RCC) by adoptive transfer of autologous T-cells that had been gene-transduced to express a single-chain antibody-G250 chimeric receptor [scFv(G250)], and encountered liver toxicity necessitating adaptation of the treatment protocol. Here, we investigate whether or not the in vivo activity of the infused scFv(G250)(+) T cells is reflected by changes of selected immune parameters measured in peripheral blood.

METHODS

ScFv(G250)-chimeric receptor-mediated functions of peripheral blood mononuclear cells (PBMC) obtained from three patients during and after treatment were compared to the same functions of scFv(G250)(+) T lymphocytes prior to infusion, and were correlated with plasma cytokine levels.

RESULTS

Prior to infusion, scFv(G250)(+) T lymphocytes showed in vitro high levels of scFv(G250)-chimeric receptor-mediated functions such as killing of CAIX(+) RCC cell lines and cytokine production upon exposure to these cells. High levels of IFN-gamma were produced, whilst production of TNF-alpha, interleukin-4 (IL-4), IL-5 and IL-10 was variable and to lower levels, and that of IL-2 virtually absent. PBMC taken from patients during therapy showed lower levels of in vitro scFv(G250)-receptor-mediated functions as compared to pre-infusion, whilst IFN-gamma was the only detectable cytokine upon in vitro PBMC exposure to CAIX. During treatment, plasma levels of IFN-gamma increased only in the patient with the most prominent liver toxicity. IL-5 plasma levels increased transiently during treatment in all patients, which may have been triggered by the co-administration of IL-2.

CONCLUSION

ScFv(G250)-receptor-mediated functions of the scFv(G250)(+) T lymphocytes are, by and large, preserved in vivo upon administration, and may be reflected by fluctuations in plasma IFN-gamma levels.

Cutting edge: syntaxin 11 regulates lymphocyte-mediated secretion and cytotoxicity

Little is known about the regulatory roles of specific soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins in cytotoxic lymphocytes. Recent information suggests that mutations in the SNARE protein syntaxin 11 result in a form of familial hemophagocytic lymphohistiocytosis (FHL). Because genetic abnormalities in key granule components (e.g., perforin) or in regulators of secretion (e.g., Munc13-4) underlie the other identified forms of FHL, we assessed whether syntaxin 11 might also serve a related regulatory role. We determined that syntaxin 11 is expressed in NK cells and activated CTLs and is located in discrete membrane-associated structures in the cytoplasm. Enhanced expression of syntaxin 11 augments the secretion and killing of tumor targets, and suppression of syntaxin 11 expression inhibits these functions. Our data identify and characterize a role for syntaxin 11 in granule exocytosis and in the generation of cell-mediated killing. These results also provide new insights on the mechanisms of hemopoietic dysregulation in FHL.

Granzyme B-induced cell death involves induction of p53 tumor suppressor gene and its activation in tumor target cells

In this study we investigated the involvement of p53 in cytotoxic T-lymphocyte (CTL)-induced tumor target cell killing mediated by the perforin/granzymes pathway. For this purpose we used a human CTL clone (LT12) that kills its autologous melanoma target cells (T1), harboring a wild type p53. We demonstrated initially that LT12 kills its T1 target in a perforin/granzymes-dependent manner. Confocal microscopy and Western blot analysis indicated that conjugate formed between LT12 and T1 resulted in rapid cytoplasmic accumulation of p53 and its activation in T1 target cells. Cytotoxic assay using recombinant granzyme B (GrB) showed that this serine protease is the predominant factor inducing such accumulation. Furthermore, RNA interference-mediated lowering of the p53 protein in T1 cells or pifithrin-alpha-induced p53-specific inhibition activity significantly decreased CTL-induced target killing mediated by CTL or recombinant GrB. This emphasizes that p53 is an important determinant in granzyme B-induced apoptosis. Our data show furthermore that when T1 cells were treated with streptolysin-O/granzyme B, specific phosphorylation of p53 at Ser-15 and Ser-37 residues was observed subsequent to the activation of the stress kinases ataxia telangiectasia mutated (ATM) and p38K. Treatment of T1 cells with pifithrin-alpha resulted in inhibition of p53 phosphorylation at these residues and in a significant decrease in GrB-induced apoptotic T1 cell death. Furthermore, small interference RNAs targeting p53 was also accompanied by an inhibition of streptolysin-O/granzyme B-induced apoptotic T1 cell death. The present study supports p53 induction after CTL-induced stress in target cells. These findings provide new insight into a potential role of p53 as a component involved in the dynamic regulation of the major pathway of CTL-mediated cell death and may have therapeutic implications.

A synergistic antitumor effect of interleukin-2 addition with CD80 immunogene therapy for peritoneal metastasis of gastric carcinoma

The co-stimulatory molecule CD80 is a ligand of CD28, which plays a key role in the induction of cell-mediated immune responses. Many tumors, including gastric cancer, decrease the expression of CD80, which results in the failure of immune recognition. We evaluated the effect of interleukin-2 addition combined with CD80 infection on the peritoneal metastasis in gastric cancer. CD80 infection combined with interleukin-2 addition significantly increased the activated cytotoxicity of mononuclear cells compared to CD80 gene infection and compared to the lacZ control group. In vivo, the survival of animals with intraperitoneal tumor was longest in those given CD80 infection with interleukin-2 addition (median survival, 46 days), followed by those given interleukin-2 (39 days), those given CD80 infection (37 days), and those given lacZ (29 days). These results suggest that interleukin-2 addition might contribute to improving the observed outcome of CD80 immunogene therapy in peritoneal metastasis of gastric carcinoma.

Neuroendocrine immunity in patients with Alzheimer's disease: toward translational epigenetics

The emerging domain of epigenetics in molecular medicine finds application for a variety of patient populations. Here, we present fundamental neuroendocrine immune evidence obtained in patients with senile dementia of the Alzheimer's type (sDAT), and discuss the implications of these data from the viewpoint of translational epigenetics of Alzheimer's disease. We followed 18 subjects with mild sDAT treated with acetylcholinesterase inhibitors, and 10 control subjects matched for age in a repeated measure design every six months for 18 months. We monitored psychosocial profile (Mini-Mental State Examination, Functional Assessment Staging, Independence in Activities of Daily Living, Depression, Profile of Moods States) in parallel to immunophenotypic parameters of T cell subpopulations by flow cytometry. Based on change in the mini-mental state score at entry and at 18 months, patients with sDAT were assigned to a "fast progression" (delta greater than 2 points) or to a "slow progression" group (delta less than or equal to 2 points). The change in circulating activated T cells (CD3+Dr+) with time in patients with sDAT was significantly inversely correlated with the change in time in natural killer (NK) cytotoxic activity to cortisol modulation in these patients, which was greater in patients with fast progression, compared to slow progression sDAT. These data indicate underlying neuroendocrine immune processes during progression of sDAT. Our observations suggest that psychoimmune measures such as those we have monitored in this study provide relevant information about the evolving physiological modulation in patients with sDAT during progression of Alzheimer's disease, and point to new or improved translational epigenetic treatment interventions.

Formins regulate the actin-related protein 2/3 complex-independent polarization of the centrosome to the immunological synapse

T cell receptor (TCR)-mediated cytoskeletal reorganization is considered to be actin-related protein (Arp) 2/3 complex dependent. We therefore examined the requirement for Arp2/3- and formin-dependent F-actin nucleation during T cell activation. We demonstrated that without Arp2/3-mediated actin nucleation, stimulated T cells could not form an F-actin-rich lamellipod, but instead produced polarized filopodia-like structures. Moreover, the microtubule-organizing center (MTOC, or centrosome), which rapidly reorients to the immunological synapse through an unknown mechanism, polarized in the absence of Arp2/3. Conversely, the actin-nucleating formins, Diaphanous-1 (DIA1) and Formin-like-1 (FMNL1), did not affect TCR-stimulated F-actin-rich structures, but instead displayed unique patterns of centrosome colocalization and controlled TCR-mediated centrosome polarization. Depletion of FMNL1 or DIA1 in cytotoxic lymphocytes abrogated cell-mediated killing. Altogether, our results have identified Arp2/3 complex-independent cytoskeletal reorganization events in T lymphocytes and indicate that formins are essential cytoskeletal regulators of centrosome polarity in T cells.

Process validation and clinical evaluation of a protocol to generate gene-modified T lymphocytes for imunogene therapy for metastatic renal cell carcinoma: GMP-controlled transduction and expansion of patient's T lymphocytes using a carboxy anhydrase IX-specific scFv transgene

BACKGROUND

Adoptive transfer of autologous T cells that are gene-transduced to express Ag-specific receptors represents an experimental strategy to provide tumor-specific immunity to cancer patients. We studied this concept in patients with metastatic renal cell cancer (RCC) using retroviral transduction of T cells with a single-chain Ab-G250 chimeric receptor [scFv(G250)]. We describe the validation of our clinical protocol for gene transduction and expansion of human T lymphocytes.

METHODS

A batch of scFv(G250) transgene-containing retrovirus was produced under conditions of good manufacturing practice (GMP). In addition to quality control and safety testing of the virus batch, extensive potency testing was performed, i.e. assessment of its functional transduction efficiency in primary human T cells. Subsequently, the clinical gene transduction and cell-expansion protocol was subjected to a series of process validations and a clinical evaluation using T cells obtained from healthy donors and three RCC patients.

RESULTS

The clinical batch of scFv(G250) transgene-containing retrovirus met the quality and safety control criteria. Small-scale transductions yielded 62-92% scFv(G250)+ T cells and, at a clinical scale, 50-84% transduction efficiencies were obtained. Patient and healthy donor T cells showed similar expansion potencies, and also yielded similar levels of scFv(G250)-mediated immune functions, i.e. specific cytolysis of G250-ligand expressing RCC cells and production of IFN-gamma upon stimulation with such cells. All T cell cultures were free of replication competent retroviruses.

DISCUSSION

We have shown that the validated batch of scFv(G250) transgene-containing retrovirus in combination with our GMP T-cell transduction and expansion protocol successfully generates clinically relevant numbers of functional scFv(G250) gene-modified T cells for patient treatment.

Physiologic modulation of natural killer cell activity as an index of Alzheimer's disease progression

Patients with Alzheimer's disease (AD) are characterized by an altered sensitivity to cortisol-mediated modulation of circulating lymphocytes. Longitudinal studies are needed to address the clinical applicability of these abnormalities as prognostic factors. Therefore, we designed a longitudinal study to address the clinical applicability of physiologic modulation of Natural Killer (NK) cell activity as a prognostic factor in AD. NK activity was assessed as baseline measurement and in response to modulation by cortisol at 10(-6)M. To verify the immunophysiological integrity of the NK cell population, we tested augmentation of NK cytotoxicity by human recombinant interleukin (IL)-2 (100 IU/ml) as control. The response to modulation by cortisol or by IL-2 was significantly greater in patients with AD. Based on change in the Mini-Mental State score at entry and at 18 months, patients with AD could be assigned to a "fast progression" (Delta > 2 points) or to a "slow progression" group (Delta Collapse

Key Words

• alzheimer's disease (ad)
• natural killer (nk) cells
• nk cytotoxic activity
• cortisol
• interleukin (il)-2
• psychoimmunology

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MESH Headings Collapse

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Affiliation(s)

Paolo Prolo Division of Oral Biology & Medicine, UCLA School of Dentistry, Los Angeles, CA 90095-1668, USA.
Francesco Chiappelli
Alberto Angeli
Andrea Dovio
Paola Perotti
Marisa Pautasso
Maria Luisa Sartori
Laura Saba
Stefano Mussino
Thomas Fraccalini
Fausto Fantó
Cristina Mocellini
Maria Gabriella Rosso
Enzo Grasso

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Immunological memory after exposure to variola virus, monkeypox virus, and vaccinia virus

We compared cellular and humoral immunity to vaccinia virus (VV) in individuals exposed to 3 different orthopoxviruses: 154 individuals previously vaccinated with VV, 7 individuals with a history of monkeypox virus infection, and 8 individuals with a history of variola virus infection. Among individuals vaccinated >20 years prior, 9 (14%) of 66 individuals demonstrated VV-specific interferon (IFN)- gamma enzyme-linked immunospot (ELISPOT) assay responses; 21 (50%) of 42 had lymphoproliferative (LP) responses, and 29 (97%) of 30 had VV-specific neutralizing antibodies. One year after monkeypox virus infection, 6 of 7 individuals had IFN- gamma ELISPOT responses, all had VV-specific LP responses, and 3 of 7 had VV-specific neutralizing antibodies. Of 8 individuals with a history of variola virus infection, 1 had a VV-specific IFN- gamma ELISPOT response, 4 had LP responses against whole VV, 7 had LP responses against heat-denatured vaccinia antigen, and 7 had VV-specific neutralizing antibodies. Survivors of variola virus infection demonstrated VV-specific CD4 memory cell responses and neutralizing antibodies >40 years after infection.

Role of beta-endorphin, corticotropin-releasing hormone, and autonomic nervous system in mediation of the effect of chronic ethanol on natural killer cell cytolytic activity

BACKGROUND

We have recently shown that alcohol feeding suppresses natural killer (NK) cell cytolytic activity partly by decreasing the function of hypothalamic beta-endorphin (beta-EP) neurons. The neuronal mechanism by which hypothalamic beta-EP communicates with the spleen to regulate the action of ethanol on NK cells is not known. In the present study, we evaluated the roles of beta-EP neurons, corticotropin releasing hormone (CRH) neurons, and the autonomic nervous system (ANS) in regulation of the ethanol effect on splenic NK cell cytolytic function.

METHODS

Male rats were fed an ethanol-containing liquid diet or control diets. These rats were used to determine the hormone release from the paraventricular nuclei (PVN) of the hypothalamus or used to determine the splenic NK cell cytolytic function after PVN administration of CRH or intraperitoneal (i.p.) administration of a ganglionic blocker chlorisondamine. The release of hormones from the PVN was measured using the push-pull perfusion method. Splenic cytolytic activity was determined using the 4-hour (51)Cr release assay against YAC-1 lymphoma target cells.

RESULTS

Alcohol feeding decreased the amount of beta-EP but increased the amount of CRH in the push-pull perfusate (PPP) samples collected from the PVN. When exogenous beta-EP was perfused into the PVN, it suppressed the release of endogenous CRH found in PPP samples of the PVN. Conversely, perfusion of an opiate antagonist naltrexone into the PVN increased the levels of endogenous CRH in PPP samples of the PVN. In addition, administration of exogenous beta-EP in the PVN stimulated the cytolytic function of NK cells, an action that was antagonized by CRH as well as by ethanol. Corticotropin-releasing hormone and ethanol alone also had an inhibitory action on NK cells. Finally, the ganglionic blocker used prevented the effect that ethanol, beta-EP, and CRH had on NK cells. These data suggest that ethanol inhibits the function of NK cells partly by suppressing the influence of the beta-EP-CRH-ANS signal to the spleen.

Lymphokine-activated killer cell susceptibility and adhesion molecule expression of multidrug resistant breast carcinoma

Reports showing susceptibility of multidrug resistant (MDR) cancer cells to immune effectors, together with P-glycoprotein (P-gp) expression in immune effector subsets, including immature natural killer (NK) cells, and some activated T cells, suggest P-gp or some changes associated with it, have implications in immune-mediated mechanisms. A series of experiments were done to determine the nature of alterations associated with susceptibility to immune effector cells of MDR tumor cells. A cell line isolated from the malignant pleural effusion of a breast cancer patient was transfected with human and murine MDR1 genes, and four variants with different levels of MDR were obtained. Lymphokine-activated killer (LAK) activity was measured by a ⁵¹Chromium release, and conjugate formation assays. MDR1 transfectant P-gp⁺ breast carcinoma lines had increased LAK susceptibility compared to their parent line. Some part of the increased LAK susceptibility of drug-resistant cell lines was at the binding/recognition level as shown by conjugate formation assays. This suggests that differences may exist between paired cell lines with respect to the expression of cell adhesion molecules (CAMs). Monoclonal antibodies (mAbs) to CAMs and flow cytometry were used to quantitate these antigens. The CAMs studied were those previously found to be upregulated by stimulating NK cells with (interleukin-2) IL-2; ICAM-1 (CD54), LFA-3 (CD58), N-CAM (CD56), and the β chain of LFA-1 (CD18). Although no differences in these CAMs were found between the breast carcinoma line and its MDR1-transfected variants, the target susceptibility results given above suggest that IL-2 treatment could be effective in combination with current protocols using chemotherapeutics, monoclonal antibodies (mAbs) and stem cell transplantation.

Fetal Ethanol Exposure Disrupts the Daily Rhythms of Splenic Granzyme B, IFN-gamma, and NK Cell Cytotoxicity in Adulthood

BACKGROUND

Circadian (and daily) rhythms are physiological events that oscillate with a 24-hour period. Circadian disruptions may hamper the immune response against infection and cancer. Several immune mechanisms, such as natural killer (NK) cell function, follow a daily rhythm. Although ethanol is known to be a potent toxin for many systems in the developing fetus, including the immune system, the long-term effects of fetal ethanol exposure on circadian immune function have not been explored.

METHODS

Daily rhythms of cytotoxic factors (granzyme B and perforin), interferon-gamma (IFN-gamma), and NK cell cytotoxic activity were determined in the spleens of adult male rats obtained from mothers who were fed during pregnancy with chow food or an ethanol-containing liquid diet or pair-fed an isocaloric liquid diet.

RESULTS

We found that adult rats exposed to ethanol during their fetal life showed a significant alteration in the physiological rhythms of granzyme B and IFN-gamma that was associated with decreased NK cell cytotoxic activity.

CONCLUSION

These data suggest that fetal ethanol exposure causes a permanent alteration of specific immune rhythms that may in part underlie the immune impairment observed in children prenatally exposed to alcohol.

Cytolytic function and survival of natural killer cells are severely altered in myelodysplastic syndromes

Natural Killer (NK) cells are critical in host defense against malignant transformation and are potent antileukemic cytotoxic effectors. In the present study, we investigated the peripheral NK function in patients with myelodysplastic syndromes (MDS). We demonstrated that the peripheral NK cell population was quantitatively normal in MDS patients. Furthermore, NK cells displayed an expression of the activating natural cytotoxicity receptors (NCR) NKp46 and NKp30 as well as NKG2D similar to that observed in donors, but exert a highly decreased constitutive cytolytic activity compared to resting normal NK cells. Although activation with IL-2 resulted in the upregulation of NKp46 expression by MDS-NK cells, their cytolytic function remained deeply altered as compared to activated donor NK cells. In addition, MDS NK cells did not proliferate in vitro, and displayed an increased rate of apoptosis in response to IL-2 stimulation although the spontaneous apoptosis was not significantly increased. Interestingly, a proportion of peripheral MDS-NK cells were derived from the MDS clone as the cytogenetic anomaly found in bone marrow karyotype was also detected in 20-50% of circulating NK cells. In conclusion, NK cells' cytolytic function and proliferative capacities in response to activation by cytokines are profoundly altered in MDS.