Role of human natural killer cells in health and disease

Stress exacerbates pancreatic cancer both directly and indirectly by creating an immunosuppressive environment

BACKGROUND/PURPOSE

Sympathetic nerve stimulation by stress exacerbates various solid tumors, including pancreatic cancer (PCa). The relationship between cancer and immunity has been suggested; however, there is limited information about the effects of nerve stimulation on immunity and cancer. We aimed to investigate the involvement of sympathetic nerve stimulation in immune cells and its effects on PCa using a restraint stress mouse model.

METHODS

In the in vitro experiment, the mouse-derived PCa cell line (LTPA) was cultured in a noradrenalin-supplemented medium. In the in vivo experiment, mice were divided into non-stress and stress groups.

RESULTS

LTPA proliferated significantly more when cultured in a noradrenalin-supplemented medium than in a normal medium. Flow cytometry analysis of blood immune cells revealed a significant decrease in B cells, T cells, and macrophages and a significant increase in myeloid-derived suppressor cells (MDSCs) in the stress group. Furthermore, a significant increase in blood noradrenaline levels was observed in the stress group (p < .01). In the PCa mice model, immune cells in the blood showed a similar trend, and the stress group had a poor prognosis. Furthermore, immunostaining at the tumor site showed that there was a lower number of B and T cells in the stress group. In addition, MDSCs were present at the tumor margins.

CONCLUSION

These results suggest that sympathetic nerve stimulation is not only directly involved in PCa growth but also exacerbates PCa by creating an immunosuppressive environment in the blood and tumor tissue.

A NK Cell Odyssey: From Bench to Therapeutics Against Hematological Malignancies

In 1975 two independent groups noticed the presence of immune cells with a unique ability to recognize and eliminate transformed hematopoietic cells without any prior sensitization or expansion of specific clones. Since then, NK cells have been the axis of thousands of studies that have resulted until June 2021, in more than 70 000 publications indexed in PubMed. As result of this work, which include approaches in vitro, in vivo, and in natura, it has been possible to appreciate the role played by the NK cells, not only as effectors against specific pathogens, but also as regulators of the immune response. Recent advances have revealed previous unidentified attributes of NK cells including the ability to adapt to new conditions under the context of chronic infections, or their ability to develop some memory-like characteristics. In this review, we will discuss significant findings that have rule our understanding of the NK cell biology, the developing of these findings into new concepts in immunology, and how these conceptual platforms are being used in the design of strategies for cancer immunotherapy.

Natural killer frequency determines natural killer cytotoxicity directly in accentuated zones and indirectly in "moderate-to-normal frequency" segment

Natural killer (NK) frequency and NK cytotoxicity (NKc) are key determining factors of a clinical outcome. In our previous study, we showed the prognostic clinical significance of immune parameters when they are beyond the optimal range (accentuated). In this study, we attempted to explain the disparity of accentuated but physiologically and immunologically normal NK parameters that might serve as negative clinical prognostics indications of failed pregnancies. We have analyzed NK%, NKc levels, and their reciprocal correlation in 2,804 patients with reproductive failures. In the entire clinical population, NK% correlates with NKc. Interestingly, we found this relationship to be strongly dependent on NK level's status. NK%-NKc correlation was the strongest (r = 0.2021, p < 0.0001) in a patient group with high NK% (> 17.5%). Patients with NK% between 15-17.5% manifested lower but still significant correlation NK%-NKc (r = 0.1213, p = 0.0155). Additionally, significant correlation (r = 0.2689, p < < 0.0001) between NK% and NKc was observed in a group of patients with NK levels < 7% (1.7-7%). While patients' groups with NK% (7-15%) did not reveal NK%-NKc association. This led us to hypothesize that the qualitative-quantitative status of NK population is responsible for their cytotoxic activity. Consistent with our hypothesis, the "balanced zone" NK% is tightly controlled, and thus does not correlate directly with NKc. In contrast, the "accentuated zones" of NK% escape this control and directly affecting NKc. Demonstrated phenomena supports our idea about the clinical significance of immune accentuation and explains its novel physiological role.

NKp30 - A prospective target for new cancer immunotherapy strategies

Natural killer (NK) cells are an important arm of the innate immune system. They constitutively express the NKp30 receptor. NKp30-mediated responses are triggered by the binding of specific ligands e.g. tumour cell-derived B7-H6 and involve the secretion of cytotoxic mediators including TNF-α, IFN-γ, perforins and granzymes. The latter two constitute a target cell-directed response that is critical in the process of immunosurveillance. The structure of NKp30 is presented, focusing on the ligand-binding site, on the ligand-induced structural changes and on the experimental data available correlating structure and binding affinity. The translation of NKp30 structural changes to disease progression is also reviewed. NKp30 role in immunotherapy has been explored in chimeric antigen receptor T-cell (CAR-T) therapy. However, antibodies or small ligands targeting NKp30 have not yet been developed. The data reviewed herein unveil the key structural aspects that must be considered for drug design in order to develop novel immunotherapy approaches.

Exercise training, circulating cytokine levels and immune function in cancer survivors: A meta-analysis

BACKGROUND

Anti-cancer therapies lead to chronic non-resolving inflammation and reduced immune function. One potential therapy is exercise training, but the effectiveness of these interventions to improve immune-related outcomes, the gaps in the literature, and recommendations to progress the field need to be determined.

OBJECTIVES

(1) to conduct separate meta-analyses in cancer survivors to determine the effects of exercise training on pro- and anti-inflammatory markers, and immune cell proportions and function; and (2) to perform subgroup analyses to determine whether exercise modality, cancer type, and specific markers help to explain heterogeneity in each meta-analysis.

DATA SOURCES

Electronic databases (PubMed/MEDLINE, EMBASE, CENTRAL, and CINAHL) from inception to March 2018. The reference lists of eligible articles and relevant reviews were also checked.

STUDY SELECTION

Inclusion criteria were adult cancer survivors from randomized controlled trials performing structured exercise intervention (aerobic, resistance or combined training or Tai Chi/yoga) compared to usual care control group and included pro-inflammatory, anti-inflammatory, and/or immune cell outcomes.

APPRAISAL AND SYNTHESIS METHODS

A total of 5349 potentially eligible articles were identified, of which 26 articles (27 trials) met the inclusion criteria. Effect sizes were calculated as standardized mean differences (SMD), where <0.2 was defined as trivial, 0.2-0.3 as small, 0.4-0.8 as moderate, and >0.8 as a large effect.

RESULTS

Exercise training decreased pro-inflammatory markers (SMD: -0.2, 95% CI: -0.4, -0.1, p < 0.001). Sub-group analysis for the pro-inflammatory markers indicated that combined aerobic and resistance training had the greatest effect (SMD: -0.3, 95% CI: -0.5, -1.9, p < 0.001), that prostate (SMD: -0.5, 95% CI: -0.8, 0.1, p = 0.004) and breast cancer populations were most responsive (SMD: -0.2, 95% CI: -0.3, -0.1, p = 0.001), and that C-reactive protein (SMD: -0.5, 95% CI: -0.9, -0.06, p = 0.025) and tumor necrosis factor (SMD: -0.3, 95% CI: -0.5, -0.06, p = 0.004) were the most sensitive to change. Exercise training tended to decrease anti-inflammatory markers (p = 0.072) but had no effect on natural killer or natural killer T cell proportions or cytotoxic activity.

CONCLUSIONS

Exercise training reduces pro-inflammatory markers in cancer survivors, with the strongest evidence for combined training and for prostate and breast cancer survivors. Further research is warranted to determine if these changes are clinically relevant or are associated with improvements in symptoms. To strengthen future research, focusing on novel immune populations that include functional parameters and standardized reporting of key immune outcomes is recommended.

Correlation Between Natural Killer Cell Activity and Systemic Inflammatory Markers for Heterogeneous Cancer Patients Treated With Wheel Balance Cancer Therapy

Background and Objective: Natural killer (NK) cells are known to have an effect on the prevention of tumorigenesis for the initial cancer, as well as the metastatic cancer. For the past several years, the relationship between cancer and inflammation has been actively studied in preclinical and clinical settings, but there are no reports on alterations in and correlation for NK cell activity (NKA) and systemic inflammatory markers. Accordingly, this study aimed to measure correlation between NKA and the levels of other systemic inflammatory markers in patients with gastric, breast, and pancreatic cancer who received Wheel Balance Cancer Therapy (WBCT). Methods: Forty-two electronic charts of patients with gastric, breast, and pancreatic cancer treated with WBCT from February 1, 2015 to September 30, 2015, were reviewed retrospectively. These charts were statistically analyzed, looking for alterations of and correlation for NKA and the expressions of systemic inflammatory markers. Results: Patients with a NKA of under 300 pg/mL at admission showed significantly higher erythrocyte sedimentation rate (ESR) and neutrophil-to-lymphocyte ratio (NLR) values and decreasing NLR values due to WBCT than patients with an NKA greater than 300 pg/mL. As a result of the correlation analysis between NKA and the levels of the systemic inflammatory markers, NKA showed significant negative correlation with NLR, ESR, and fibrinogen values. Conclusions: Negative correlation was identified between NKA and NLR, NKA and ESR, and NKA and fibrinogen in patients with heterogeneous cancer patients.

Radiation alters PD-L1/NKG2D ligand levels in lung cancer cells and leads to immune escape from NK cell cytotoxicity via IL-6-MEK/Erk signaling pathway

We investigated whether radiation influences the susceptibility of non-small cell lung cancer (NSCLC) cells to NK cell mediated cytotoxicity. We found radiation treatment increased expression of programmed cell death ligand 1 (PD-L1), but decreased NK group 2, member D (NKG2D) ligand expressions in A549 and H157 NSCLC cells. Both types of changes would have protected tumor cells from the cytotoxic action of NK cells. Consistently, we detected similar alteration in these molecules in radioresistant A549R26-1 and H157R24-1 subline cells. Higher PD-L1 level was also observed in tumors of A549R26-1 cell-derived xenografts than tumors of parental A549 (A549P) cell-derived xenografts. Accordingly, we found radioresistant cells were more resistant to the cytotoxic action of NK cells than parental cells, and such resistance was decreased when neutralizing antibody (Ab) of PD-L1 was added to the radioresistant cell/NK cell co-cultures. In mechanism studies, we found that IL-6-MEK/Erk signaling contributed most significantly to the up-regulation of PD-L1/down-regulation of NKG2D ligands in radioresistant cells. The addition of the MEK/Erk inhibitor increased the susceptibility of A549R26-1 and H157R24-1 cells to NK-cell cytotoxicity while no significant effect was observed in parental cells. Moreover, we detected enhanced NK-cell cytotoxicity to radioresistant cells when PD-L1 Ab and MEK/Erk inhibitor were added together to co-cultures of tumor/NK cells compared to when PD-L1 Ab was used alone. We suggest that combined use of PD-L1 Ab and MEK/Erk inhibitor may offer better therapeutic benefits than PD-L1 Ab alone to treat NSCLC patients who are receiving radiotherapy or who are at the radioresistant stage.

Natural killer cells in placentation and cancer: Implications for hypertension during pregnancy

Hypertension during pregnancy is the most common medical condition encountered during gestation. Despite this, knowledge of the mechanisms that underlie the disease and the development of new therapies are limited. Hypertension during pregnancy and some forms of cancer confer an increased risk to the development of cardiovascular disease later in life; one mechanism which may link these conditions is the involvement of natural killer (NK) cells. Whilst immunology and immunotherapy are well-developed areas in oncology; the complex mechanisms of the immune system in health and disease at the maternal-fetal interface are less well-defined. Natural killer (NK) cells have emerged as key immune cells involved in physiology and pathology of pregnancy. These small lymphocytes are present in the decidua (the uterine-specific uNK cells) and are distinct from peripheral NK cells. The uNK cell population plays a vital role in mediating trophoblast invasion and affecting decidual vascular remodelling whereas the role of the peripheral NK cell population during pregnancy is less well-defined. This review will give an overview of NK cell biology followed by a discussion of the current evidence for the role of uterine and peripheral NK cells at the maternal-fetal interface in health and disease. Furthermore, examples of NK cell research from cancer biology will be employed to inform future directions of research. By combining this knowledge from oncology where the field of immunotherapy has now matured into clinical trials; it is hopeful that new mechanisms can be elucidated to generate targets for similar therapeutic strategies for women with hypertensive pregnancies where interventions are needed.

Role of interleukin-18 in the pathophysiology of allergic diseases

Interleukin (IL)-18 is an IL-1 family cytokine expressed by macrophages, dendritic cells, epithelial cells, and keratinocytes and is implicated in various aspects of both the innate and adaptive immune systems. IL-18 signals similar to IL-1β intracellularly to activate gene transcription. Since its discovery, IL-18 has been demonstrated to play a key role in pathogen defense from helminths and some bacteria. Recently however, evidence has accumulated that IL-18 expression is increased in many presentations of allergic disease. A pathologic role for IL-18 includes stimulating mast cell and basophil degranulation, recruiting granulocytes to sites of inflammation, increasing cytotoxic activity of natural killer (NK) and NK-T cells, inducing Immunoglobulin (Ig)E production and isotype switching, and affecting a broad range of T cells to promote a type II helper T cell (Th2) response. Evidence and importance of these effects are presented, including novel results from our lab implicating IL-18 in the direct expansion of mast cells, basophils, and other myeloid-lineage cells from bone-marrow precursors. The development of urticaria, asthma, dermatitis, rhinitis, and eosinophilic disorders all have demonstrated correlations to increased IL-18 levels either in the tissue or systemically. IL-18 represents a novel site of immune regulation in not only allergic conditions, but also autoimmune diseases and other instances of aberrant immune functioning. Diagrammatic summarized abstract for readers convinance is presented in Fig. 1.

Immunotoxicity Evaluation of Resorcinol Bis-Diphenylphosphate (Fyrolflex RDP) in B6C3F1 Mice

RDP was administered daily to groups of female B6C3F1 mice by oral gavage for 28 days at dose levels of 500, 1500, or 5000 mg/kg/day body weight (BW). Control animals were sham dosed. Animals were euthanized 1 day following final exposure or following a 60-day recovery period. End point observations included necropsy and histopathology, spleen and thymus weights and cellularity, peritoneal cell numbers and differential cell analysis, splenic natural killer (NK) cell activity, lymphocyte blastogenesis, antibody-forming cell (AFC) response, peritoneal macrophage phagocytic activity, and host susceptibility to Listeria monocytogenes infection. In-life observations included weekly clinical examinations and body weights. No adverse clinical signs were noted and the only significant finding was an increase in body weight in high dose mice on week 4 as compared to sham controls. Small changes in body weight gain were seen in all dose groups as compared to sham controls after completion of dosing on weeks 5 and 6 and in mid-dose mice on weeks 7 and 12. No significant differences were found in spleen and thymus weights or in cellularity. No changes were found in peritoneal cell numbers or cell types, peritoneal macrophage phagocytic activity, or host susceptibility to infection. Likewise, splenic NK cell activity, lymphocyte blastogenesis, and AFC function were also unaffected. No histopathologic changes were observed. All animals that received positive-control substances demonstrated a significant effect in the respective tests. In conclusion, a standardized and validated battery of immune function tests demonstrated no immunotoxicity following daily oral exposure to up to 5000 mg/kg BW of RDP for 28 days.

Phenotypic analysis of immunocompetent cells in healthy human dental pulp

INTRODUCTION

Like other tissues in the body, the human dental pulp is equipped with a network of immune cells that can be mobilized against pathogens when they invade the tooth. Very little data, mostly obtained with classic histologic methods, have reported their quantities and relative percentages. The objective of this study was to characterize and precisely quantify immunocompetent cells in healthy human dental pulp by using fluorescence-activated cell sorting, together with identifying specific cell subsets in the leukocyte (CD45(+)) cells.

METHODS

Healthy human third molars were collected from 42 young patients. Dental pulps were separated from the hard tissues and prepared for flow cytometry or immunostaining analyses.

RESULTS

CD45(+) cells represented 0.94% ± 0.65% of cells obtained from the enzymatic digestion of whole dental pulps (n = 34). CD16(+)CD14(+) granulocytes/neutrophils (50.01% ± 9.08%, n = 7) were found to represent the major subpopulation in CD45(+) cells followed by CD3(+) T lymphocytes (32.58% ± 11%, n = 17), CD14(+) monocytes (8.93% ± 5.8%, n = 7), and HLA-DR(high) Lin1(-) dendritic cells (4.51% ± 1.12%, n = 7). Minor subpopulations included CD3(-)CD56(+) natural killer cells (2.63% ± 1.15%, n = 7) and CD19(+) B lymphocytes (1.65% ± 0.89%, n = 17). We further identified cells harboring a phenotype compatible with Foxp3/CD25-expressing regulatory T lymphocytes (CD45(+)CD3(+)CD4(+)CD127(low)). Fluorescence-activated cell sorting analysis and confocal microscopy also revealed expression of HO-1 in HLA-DR(+) cells.

CONCLUSIONS

For the first time, this study identifies and precisely quantifies the relative proportion of immunocompetent cells potentially involved in tissue homeostasis of healthy human dental pulp.

Stimulation of natural killer cells by homoeopathic complexes: an in vitro and in vivo pilot study in advanced cancer patients

The present study was designed in order to evaluate the effects of five homoeopathic complex preparations on functional activity natural killer cells (NKCs) in advanced cancer patients. We examined the effects of Coenzyme Compositum®, Ubichinon Compositum®, Glyoxal Compositum®, Katalysatoren® and Traumeel® on the functional activity of NKCs. Experimental procedures included in vitro and in vivo trials. The in vitro trials were performed in NKCs isolated from 12 healthy volunteers (aged 44 ± 4 years) and incubated with the five homoeopathic complex preparations. The in vivo trials were performed in 15 advanced cancer patients (aged 55 ± 12 years) supplemented for 3 months with the homoeopathic preparations. All five homoeopathic preparations significantly increased the cytotoxic activity of the NKCs at the lowest NKCs/target cell ratio 12:1 (p < 0·05). The order of activity was: Ubichinon Compositum® > Glyoxal Compositum® > Katalysatoren® > Traumeel® > Coenzyme Compositum®. In the advanced cancer patients, the homoeopathic preparation significantly increased NKCs cytotoxic activity (p < 0·05). The homoeopathic complex preparations tested in this study can be used as an adjuvant immunotherapy in advanced cancer patients.

A randomized placebo-controlled trial of massage therapy on the immune system of preterm infants

OBJECTIVES

The aim of this study was to investigate the effects of massage therapy (MT) on the immune system of preterm infants. The primary hypothesis was that MT compared with sham therapy (control) will enhance the immune system of stable premature infants by increasing the proportion of their natural killer (NK) cell numbers.

METHODS

A randomized placebo-controlled trial of MT versus sham therapy (control) was conducted among stable premature infants in the NICU. Study intervention was provided 5 days per week until hospital discharge for a maximum of 4 weeks. Immunologic evaluations (absolute NK cells, T and B cells, T cell subsets, and NK cytotoxicity), weight, number of infections, and length of hospital stay were also evaluated.

RESULTS

The study enrolled 120 infants (58 massage; 62 control). At the end of the study, absolute NK cells were not different between the 2 groups; however, NK cytotoxicity was higher in the massage group, particularly among those who received ≥5 consecutive days of study intervention compared with control (13.79 vs 10 lytic units, respectively; P = .04). Infants in the massage group were heavier at end of study and had greater daily weight gain compared with those in the control group; other immunologic parameters, number of infections, and length of stay were not different between the 2 groups.

CONCLUSIONS

In this study, MT administered to stable preterm infants was associated with higher NK cytotoxicity and more daily weight gain. MT may improve the overall outcome of these infants. Larger studies are needed.

NF-κB regulates MICA gene transcription in endothelial cell through a genetically inhibitable control site

Endothelial cells form a barrier between blood and the underlying vessel wall, which characteristically demonstrates inflammatory damage in atherosclerotic disease. MICA is a highly polymorphic ligand for the activating immune receptor NKG2D and can be expressed on endothelial cells. We hypothesized that damaged vessel walls, such as those involved in atherosclerosis, might express MICA, which could contribute to the vascular immunopathology. Immune activation resulting from MICA expression could play a significant role in the development of vascular damage. We have demonstrated that TNFα up-regulates MICA on human endothelial cells. The up-regulation is mediated by NF-κB, and we have defined the regulatory control site responsible for this at -130 bp upstream of the MICA transcription start site. This site overlaps with a heat shock response element and integrates input from the two pathways. We have shown that in atherosclerotic lesions there is expression of MICA on endothelial cells. Using lentivirus-mediated gene delivery in primary human endothelial cells, we were able to inhibit the MICA response to TNFα with a truncated HSF1 that lacked a transactivation domain. This highlights the potential for transcription-based therapeutic approaches in atherosclerotic vascular disease to reduce immune-mediated endothelial and vessel wall damage.

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.

Measurement of NK activity in whole blood by the CD69 up-regulation after co-incubation with K562, comparison with NK cytotoxicity assays and CD107a degranulation assay

In present study human peripheral blood NK cell activation after co-incubation with K569 cell line was investigated by CD69 expression. NK lytic activity was studied by two different assays: TDA (2,2':6',2″-terpyridine-6,6″-dicarboxylate) release assay (TRA) and flow cytometry assay (FCA) that display two approach to cytotoxicity measurement. We also investigated NK cell degranulation activity by estimation of CD107a (LAMPa) expression. Comparison of specific lysis value measured by both cytotoxicity assays showed high correlation coefficient between two methods (r=0.94447). Specific lysis value correlated significantly with CD69+ NK frequency and NK degranulation activity. We show that lymphocyte incubation with K562 results to increase CD69 expression on NK and NKT but not on T lymphocytes. Only a part of peripheral blood NK cells became CD69 positive after incubation with excess of K562 cells. CD69+ NK cell frequencies did not increase after elevation of K562/NK ratio or incubation period that confirmed existence of subset of NK cells able to response to K562. CD69 elevation on NK significantly correlated with NK cytotoxicity (r=0.726). CD69 increases were similar when whole blood or isolated PBMC was used in assay. We also found different capacity to activation in NK subsets that express CD62L at various densities. The results demonstrated that K562 induced CD69 expression displays NK lymphocyte functional condition that associated with cytotoxic function.

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.

Bariatric surgery reverses natural killer (NK) cell activity and NK-related cytokine synthesis impairment induced by morbid obesity

BACKGROUND

Obesity is related to a higher rate of infections and some types of cancer. Here we analyzed the impact of obesity and weight loss induced by Roux-en-Y gastric bypass (RYGB) on immunological parameters, i.e., cytokine productions and natural killer cell function.

METHODS

We analyzed 28 morbidly obese patients before and 6 months after RYGB. Biochemical parameters were analyzed in plasma. The percent of natural killer (NK) cells, their cytotoxicity, and the production of cytokines by peripheral blood mononuclear cells were analyzed. The percent of NK cells was determined by flow cytometry and cytokine production determined by enzyme-linked immunosorbent assay. NK cytotoxicity was determined by the lactate dehydrogenase release assay.

RESULTS

The weight loss 6 months following surgery was 35.3 ± 4.5 kg. RYGB also improves biochemical parameters. No significant difference was found in the percent of NK cells after surgery. We found an increase in the production of interferon-γ, interleukin (IL)-12 and IL-18, but not in IL-2, 6 months after RYGB. Cytotoxic activity of NK cells was significantly enhanced 6 months after RYGB [17.1 ± 14.7% before RYGB vs 51.8 ± 11.3% at 6 months after, at 40:1 effector to target cell ratio; p < 0.001]. We observed significant post-surgical improvement in the cytotoxic activity curve in 22 out of 28 patients (78.6%), irrespective of the target to effector cell ratio.

CONCLUSIONS

The weight loss induced by RYGB modifies the production of cytokines related with NK cell function and improves its activity.

Deletion of galectin-3 in the host attenuates metastasis of murine melanoma by modulating tumor adhesion and NK cell activity

Galectin-3, a β galactoside-binding lectin, plays an important role in the processes relevant to tumorigenesis such as malignant cell transformation, invasion and metastasis. We have investigated whether deletion of Galectin-3 in the host affects the metastasis of B16F1 malignant melanoma. Galectin-3-deficient (Gal-3(-/-)) mice are more resistant to metastatic malignant melanoma as evaluated by number and size of metastatic colonies in the lung. In vitro assays showed lower number of attached malignant cells in the tissue section derived from Gal-3(-/-) mice. Furthermore, lack of Galectin-3 correlates with higher serum levels of IFN-γ and IL-17 in tumor bearing hosts. Interestingly, spleens of Gal-3(-/-) mice have lower number of Foxp3(+) T cells after injection of B16F1 melanoma cells. Finally, we found that while CD8(+) T cell and adherent cell cytotoxicity were similar, there was greater cytotoxic activity of splenic NK cells of Gal-3(-/-) mice compared with "wild-type" (Gal-3( +/+ )) mice. Despite the reduction in total number of CD3ε(-)NK1.1(+), Gal-3(-/-) mice constitutively have a significantly higher percentage of effective cytotoxic CD27(high)CD11b(high) NK cells as well as the percentage of immature CD27(high)CD11b(low) NK cells. In contrast, CD27(low)CD11b(high) less functionally exhausted NK cells and NK cells bearing inhibitory KLRG1 receptor were more numerous in Gal-3( +/+ ) mice. It appears that lack of Galectin-3 affects tumor metastasis by at least two independent mechanisms: by a decrease in binding of melanoma cells onto target tissue and by enhanced NK-mediated anti-tumor response suggesting that Galectin-3 may be considered as therapeutic target.

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.

Does analgesia and condition influence immunity after surgery? Effects of fentanyl, ketamine and clonidine on natural killer activity at different ages

BACKGROUND AND OBJECTIVE

Cellular immunity varies in the perioperative period. We evaluated the effects of fentanyl, clonidine and ketamine at different time points after surgery and in animals in different conditions (young vs. old).

MATERIALS AND METHODS

Rats undergoing laparotomy under sevoflurane anaesthesia were assigned to receive saline, fentanyl (40 microg kg(-1)), clonidine (10 microg kg(-1)) or ketamine (10 mg kg(-1)) 1 h before surgery. Natural killer (NK) activity was quantified at different time points (immediately or after 18, 24, 48, 72 h and 8 days) in vitro by the lysis of YAC-1 cells. In-vivo assessment included counting the number of lung metastases induced by the MADB-106 cells.

RESULTS

During the first 24 h after surgery, a rapid increase in NK activity was noted, followed by a significant depression returning to baseline at 8 days. Analgesics show specific effects: fentanyl depressed NK activity with or without surgery. Clonidine depressed NK activity in nonoperated animals and during the first 24 h after surgery. Ketamine depressed NK activity in nonoperated animals but, after surgery, this activity varied with the same time course as saline. Ketamine and clonidine significantly reduced the number of lung metastases in operated animals. Ketamine significantly reduced the number of metastases in old nonoperated animals. Finally, ageing has a significant negative influence.

CONCLUSION

Surgery, analgesics and co-existing conditions significantly influence cellular immunity. The importance of these changes varies with time. Fentanyl had a worse influence than clonidine and ketamine, but seemed equally protective against the development of metastases.

Variation of human natural killer cell phenotypes with age: identification of a unique KLRG1-negative subset

Human natural killer (NK) cells subsets are phenotypically characterized by their lack of CD3 and low/high expression of CD56. This study revealed an age-associated increase in the ratio of CD3(-)CD56(dim) to CD3(-)CD56(bright) NK cells, whereas distinct expression patterns of CD2, CD16, CD57, and the C-type lectin family members killer cell lectin-like receptor -D1 (CD94) and -G1 (KLRG1), were noted on both these NK and the CD3(+)CD56(+) T cell subsets; moreover, CD94 and KLRG1 expression were significantly reduced with age. Although the proportion of CD3(-)CD56(bright) NK cells vs CD3(-)CD56(dim) cells decreased with age, the percentage of CD3(-)CD56(bright) cells expressing IFN-gamma after activation significantly increased, potentially representing compensatory augmentation of cytokine production to maintain the important immunoregulatory role of these cells in older individuals. Collectively, these results highlight new evidence for a continuum of change during immunologic aging and present unique data for variation of NK cell subsets with human aging.

The effect of stress on the defense systems

Acute stress increases resistance to infection. The alteration of this mechanism in chronically stressed people impairs the organism's ability to mount a strong immune response with a resultant increase in morbidity. Acute stress induces a probable sympatho-adrenergically mediated increase in chemotaxis and adhesion molecules expression, thus promoting immune cells migration to sites of infection and/or inflammation, while chronic stress impairs this mechanism. Protracted stressful conditions decrease NK cytotoxic capacity. There is a substance P, which under stressful circumstances mediates the increase in macrophage cytokine production. Acute stress increases T cell mobilization through a beta2-adrenergically mediated process, which is blunted during chronic stress. Psychological stress impairs the immune system's ability to produce antibodies in response to a vaccine, thereby making the organism more vulnerable to infections.

Regulation of NK cell trafficking by CD81

NK cells, a heterogeneous sub-population of lymphocytes, are critically involved in the regulation of both innate and adaptive immune responses in humans. Besides their participation in the control of tumors and viral infections, they also regulate inflammatory processes, mediating both beneficial and detrimental effects. To effectively fulfil their role in immune surveillance, proper trafficking of NK cells is essential. However, the mechanisms and factors governing NK cell recruitment are only poorly dissected. Here, we describe the functional role of tetraspanins, a family of evolutionary conserved cell-surface proteins, in modulating migration and transmigration of human NK cells. We demonstrate expression of various tetraspanins on NK cells. Furthermore, we show that stimulation of the NK cell-expressed tetraspanin CD81 induces phosphorylation of ezrin/radixin/moesin proteins and leads to NK cell polarization thereby facilitating NK cell migration toward various chemokines/cytokines. Finally, we provide evidence for a role of CD81 in promoting adhesion of NK cells to components of the extracellular matrix, a prerequisite for extravasation of lymphocytes in inflamed tissues. Thus, our data suggest that the tetraspanin CD81 is importantly involved in the regulation of NK cell recruitment.

[Could anaesthesia, analgesia and sympathetic modulation affect neoplasic recurrence after surgery? A systematic review centred over the modulation of natural killer cells activity]

OBJECTIVE

The Natural Killer cells (NK) are an important part of non-specific cellular-mediated and antitumoral immunity. The goal of this review is to recapitulate data published over NK activity during the perioperative period and the influence of anaesthesia, analgesia and modulation of sympathetic system.

DATA SOURCES

Pubmed/Medline database.

STUDY SELECTION AND DATA EXTRACTION

Keywords-based selection, without limit of date: fundamental studies, randomized controlled trials and non-randomized comparative studies.

DATA SYNTHESIS

In human as in animal studies, an important correlation exists between NK activity and prognosis linked to the development of metastasis. The great depression of this cytotoxicity during the perioperative period could be able to compromise host defenses. The influence of anaesthetics and analgesics is important. The effects of the opioids, the agonists and the antagonists of the sympathetic nervous system, the prostaglandins, the NSAIDs, the ketamine, the hypnotics and the locoregional anaesthesia are systematically reviewed. The limits of experimental model presented are covered.

CONCLUSION

The effects of anaesthetic/analgesic drugs and techniques, the consequences of sympathomodulation on NK activity are numerous and sometimes opposite. It is important for the anaesthesiologist to keep in mind that the long term consequences of his techniques on the patients' outcome must be clarified.

Perioperative pain, psychological distress, and immune function in men undergoing prostatectomy for cancer of the prostate

Prostate cancer is a leading malignancy in men, and prostatectomy is widely used for its treatment. Psychological distress and pain are commonly experienced in the perioperative period, and both can contribute to suppression of the immune response to cancer. This study evaluated perioperative pain, psychological distress, and immune function in men undergoing prostatectomy. Men were evaluated prior to surgery, 1 and 2 days postoperatively and 4-6 weeks postoperatively. Compared to cancer-free men, the prostatectomy group reported increased perceived stress, depression, confusion, and anxiety prior to surgery. During the 2 postoperative days, mood disturbance and anxiety persisted and were accompanied by mild elevations in pain and reduced vigor. At 4-6 weeks postoperative, mood, pain, and immune function were similar to those of the cancer-free group; however, the prostatectomy group continued to report significant elevations in anxiety. Natural killer cell activity (NKCA) was significantly reduced on Day 1 after prostatectomy, but by postoperative Day 2, NKCA returned to a level similar to that of the cancer-free group. The reduction in NKCA was not accompanied by changes in circulating immune cells, demonstrating that this reduction represented a functional change in NKCA. No correlations between immune variables and pain or psychological variables were found, suggesting that the postoperative reduction in NKCA was likely the result of the physical stress of the surgical experience. Suppression of immune defenses during the critical postoperative period can place cancer patients at risk for nascent tumor seeding. Additional interventions are needed to reduce this risk.

Natural killer activity of peripheral-blood mononuclear cells in breast cancer patients

Natural killer (NK) activity of immune cells plays a central role in host defense against cancer and virus-infected cells. Natural cytotoxic activity of peripheral-blood mononuclear cells was assessed by a Calcein-AM release assay in 89 subjects. In the present study, we here demonstrated that NK activities of peripheral-blood mononuclear cells (PBMCs) from breast cancer patients were significantly lower as compared with that of healthy individuals. There were significant differences in the NK activities of PBMCs from HER2-negative breast cancer patients as compared with HER2-positive patients. Our results suggest that NK activity of PBMCs is lower in breast cancer indicating a role for immunological natural host defense mechanisms against cancer.

Measurement of cytotoxic activity of NK/LAK cells

In this unit, methodology is presented for measuring the capacity of human natural killer (NK) or lymphokine-activated killer (LAK) cells to lyse tumor cell targets. Cytotoxicity of these effector cells is evaluated in a short-term (51)Cr-release assay using NK-sensitive tumor cells as the targets for NK cells or NK-resistant tumor cells as the targets for LAK cells. In the basic protocol, a generic (51)Cr-release assay is described in which PBMC, purified NK cells or interleukin 2 (IL-2)-activated lymphocyte populations (LAK cells) are utilized as effector cells. Support protocols describe preparation of nonadherent tumor cells, cells obtained from malignant effusions, trypsinized tumor cells from adherent monolayer culture, or freshly isolated tumor cells from surgical specimens. All of these cell types can serve as the (51)Cr-labeled target cells in the basic protocol. The procedure for labeling target cells from any of these sources with (51)Cr is also provided.

Psychological distress, killer lymphocytes and disease severity in HIV/AIDS

Immunocellular mechanisms that account for the association between psychosocial risk factors and increased susceptibility to faster progression of HIV/AIDS are largely unknown. This study used structural equation modeling to test the hypothesis that enumerative and functional alterations in killer lymphocytes mediate the relationship between higher levels of psychological distress (defined by perceived stress, anxiety and depressive symptoms) and greater HIV disease severity (defined by HIV-1 viral load and T-helper (CD4(+)) cell count), independent of standard demographic and various HIV-related covariates. Participants were 200 HIV-1 seropositive adults on combination antiretroviral therapy (ages 20-55 years; 67% men; 62% black; 84% AIDS). The data fit a psychoimmune model in which the significant relationship between higher distress levels and greater disease severity was mediated by diminished natural killer (NK) cell count and cytotoxic function, as well as increased cytotoxic (CD8(+)) T-cell activation. Overall the findings indicated that the psychoimmune model accounted for 67% of the variation in HIV disease severity. In contrast, the data did not support a reverse directionality mediation model, where greater HIV disease severity predicted greater distress as a function of killer lymphocyte status. In sum, the psychoimmune associations of the final model are physiologically consistent and suggest that distress-related alterations in killer lymphocyte immunity may play a role in the biobehavioral mechanisms linked with HIV-1 pathogenesis.

Positive psychosocial factors and NKT cells in ovarian cancer patients

Psychosocial factors are known to be associated with properties of both NK cells and T cells in cancer patients. Less is known about the relationship between psychosocial factors and NKT cells, a rare group of lymphocytes that have known relevance for tumor control. We examined four psychosocial factors and percentage and number of CD3+CD56+ NKT cells, CD3-CD56+ NK cells, and CD3+CD56- T cells in peripheral blood lymphocytes (PBL), ascites, and tumor of 35 ovarian cancer patients and 28 patients with benign pelvic masses. Patients awaiting surgery for a suspected cancerous mass completed questionnaires and gave a pre-surgical blood sample. Ascites and tumor were taken during surgery. After lymphocyte isolation, subpopulations were analyzed by flow cytometry. Benign and cancer patients did not differ on PBL subpopulations. Among cancer patients, NKT cell percentage was significantly higher in tumor and ascites than in PBL; T cell percentage was significantly higher in PBL than tumor. NKT, NK, and T cell number were significantly higher in peripheral blood than in ascites. Positive reframing was related to significantly higher NKT cell percentage and number in PBL. Social support was related to significantly higher NKT cell percentage in tumor. Vigor was related to significantly higher NKT cell percentage in PBL. Total mood disturbance was not related to NKT cell percentage or number. No significant relationships were found between psychosocial factors and NK cell percentage and number and T cell percentage and number. Given the anti-tumor activity of CD3+CD56+ cells, these relationships may have relevance for cancer control.

Developmental pathways that generate natural-killer-cell diversity in mice and humans

Natural killer (NK) cells are large granular lymphocytes capable of producing inflammatory cytokines and spontaneously killing malignant, infected or 'stressed' cells. These NK-cell functions are controlled by cell-surface receptors that titrate stimulatory and inhibitory signals. However, we remain puzzled about where and when NK cells develop and differentiate, and this has fuelled the debate over the diversification of the peripheral NK-cell pool: are NK cells functionally homogeneous or are there subsets with specialized effector functions? In this Review, we consider the developmental relationships and biological significance of the diverse NK-cell subsets in mice and humans, and discuss how new humanized mouse models may help to characterize them further.

Oral administration of high molecular mass poly-gamma-glutamate induces NK cell-mediated antitumor immunity

We analyzed the in vivo tumor regression activity of high molecular mass poly-gamma-glutamate (gamma-PGA) from Bacillus subtilis sups. chungkookjang. C57BL/6 mice were orally administered 10-, 100-, or 2000-kDa gamma-PGA or beta-glucan (positive control), and antitumor immunity was examined. Our results revealed higher levels of NK cell-mediated cytotoxicity and IFN-gamma secretion in mice treated with higher molecular mass gamma-PGA (2000 kDa) vs those treated with lower molecular mass gamma-PGA (10 or 100 kDa) or beta-glucan. We then examined the effect of oral administration of 10- or 2000-kDa gamma-PGA on protection against B16 tumor challenge in C57BL/6 mice. Mice receiving high molecular mass gamma-PGA (2000 kDa) showed significantly smaller tumor sizes following challenge with the MHC class I-down-regulated tumor cell lines, B16 and TC-1 P3 (A15), but not with TC-1 cells, which have normal MHC class I expression. Lastly, we found that gamma-PGA-induced antitumor effect was decreased by in vivo depletion of NK cells using mAb PK136 or anti-asialo GM1 Ab, and that was completely blocked in NK cell-deficient B6 beige mice or IFN-gamma knockout mice. Taken together, we demonstrated that oral administration of high molecular mass gamma-PGA (2000 kDa) generated significant NK cell-mediated antitumor activity in mice bearing MHC class I-deficient tumors.

Association of vitamin A deficiency with decrease in TNF-α expressing CD3-CD56+ NK cells in Ghanaians

Although low plasma vitamin A concentrations are associated with increased incidence or severity of infections such as respiratory tract infection and measles in children, there is a paucity of data on the effect of vitamin A deficiency on the distribution of, and cytokine production by, the different cellular immune subsets in humans. We conducted a cross-sectional study in a district in Ghana to characterize cellular subsets and functional capacity of peripheral blood mononuclear cells from vitamin A deficient and vitamin A sufficient (normal) individuals, and evaluated the relationships between vitamin A concentration in plasma and cellular immune status. We measured the percentages of selected cellular phenotypes and intracellular cytokine expression and describe the differential cellular subset distributions and alterations in cytokine expression in participants with normal and deficient vitamin A concentrations. The major change observed in the constitution of cellular subsets was a decrease in TNF-α expressing CD3-CD56+ NK cells in those with vitamin A deficiency compared with normal individuals. CD4+ T cell proliferation and production of IFN-γ and IL-4 were not statistically different between the two groups. These results support previous studies that demonstrated decreased NK cell activity in vitamin A deficient animals. The decrease in TNF-α expressing NK cells observed in vitamin A deficient individuals in this study could help to explain the decreased resistance to infections observed in those with vitamin A deficiency.

A novel multiparametric flow cytometry-based cytotoxicity assay simultaneously immunophenotypes effector cells: comparisons to a 4 h 51Cr-release assay

Natural killer (NK) cell-or T cell-mediated cytotoxicity traditionally is measured in 4-16 h (51)Cr-release assays (CRA). A new four-color flow cytometry-based cytotoxicity assay (FCC) was developed to simultaneously measure NK cell cytotoxicity and NK cell phenotype (CD3(-)CD16(+)CD56(+)). Target cells, K562 or Daudi, were labeled with Cell Tracker Orange (CTO) prior to the addition of effector cells. Following co-incubation, 7 amino-actinomycin D (7-AAD) was added to measure death of target cells. The phenotype of effectors, viability of targets, the formation of tumor-effector cell conjugates and absolute numbers of all cells were measured based on light scatter (FSC/SSC), double discrimination of the fluorescence peak integral and height, and fluorescence intensity. Kinetic studies (0.5 and 1 to 4 h) at different effector to target (E:T) cell ratios (50, 25, 12, and 6) confirmed that the 3 h incubation was optimal. The FCC assay is more sensitive than the CRA, has a coefficient of variation (CV) 8-13% and reliably measures NK cell-or lymphokine-activated killer (LAK) cell-mediated killing of target cells in normal controls and subjects with cancer. The FCC assay can be used to study a range of phenotypic attributes, in addition to lytic activity of various subsets of effector cells, without radioactive tracers and thus, it is relatively inexpensive. The FCC assay has a potential for providing information about molecular interactions underlying target cell lysis and thus becoming a major tool for studies of disease pathogenesis as well as development of novel immune therapies.

Cellular liaisons of natural killer lymphocytes in immunology and immunotherapy of cancer

There is compelling evidence for the role of natural killer (NK) cells in tumor immunosurveillance and their beneficial effects on many experimentally successful immunotherapy strategies. NK cells mediate cell contact-dependent cellular cytotoxicity and produce pro-inflammatory cytokines, but do not rearrange antigen receptors. Their activation depends on various germline-encoded receptors, including CD16, which mediates recognition of antibody-coated target cells. NK cytotoxicity is checked by a repertoire of inhibitory receptors that scan adequate expression of major histocompatibility complex class I molecules on the potential target cell. Functional cross-talk of NK and dendritic cells suggests a critical role for NK cells in the initiation and regulation of cellular immunity. Considerable knowledge on the molecular basis of NK recognition/activation contrasts with a lack of successful translational research on these matters. However, there is plenty of opportunity for targeted intervention of inhibitory/activatory surface receptors and for adoptive cell therapy with autologous or allogeneic NK cells.

Host immune status and incidence of hepatocellular carcinoma among subjects infected with hepatitis C virus: a nested case-control study in Japan

A nested case-control study was conducted to examine the association between host immune status, as characterized by serum immune marker levels, and the development of hepatocellular carcinoma (HCC) up to 8 years later in persons with chronic hepatitis C virus (HCV) infection. Cases (n = 39) and matched controls (n = 117) were selected from participants of the Town C HCV Study in Japan between 1996 and 2004 and matched on age at first available sample (+/-1 year), gender, and length of follow-up. Separate analyses were done for each of three serum immune markers: soluble tumor necrosis factor-receptor II (sTNF-R2) and soluble intercellular adhesion molecule-1 (sICAM-1), as indicators of type 1, cell-mediated immune response, and soluble CD30 (sCD30), as an indicator of type 2, humoral immune response. The median concentrations of sTNF-R2, sICAM-1, and sCD30 among controls were 3,170 pg/mL, 305 ng/mL, and 3.0 units/mL, respectively, and were higher among cases (3,870 pg/mL, 372 ng/mL, and 3.3 units/mL, respectively). The risk of developing HCC among subjects with immune marker concentrations above the median levels of the controls was >2-fold greater than among subjects with lower concentrations for all three markers [sTNF-R2: odds ratio (OR), 6.9; 95% confidence interval (95% CI), 2.4-20.5; sICAM-1: OR, 2.0; 95% CI, 0.9-4.1; and sCD30: OR, 2.1; 95% CI, 1.0-4.7]. Simultaneous adjustment for all three markers revealed only sTNF-R2 to be associated with HCC risk (OR, 6.4; 95% CI, 2.0-20.6). Adjustment for alcohol consumption and HCV serotype did not materially alter these associations. Results from this prospective, community-based study suggest that a dysregulation in both type 1-related and type 2-related host immunity contributes to the development of HCV-associated HCC.