Natural cytotoxic activity of peripheral-blood lymphocytes and cancer incidence: an 11-year follow-up study of a general population

Leukemic priming of resting NK cells is killer Ig-like receptor independent but requires CD15-mediated CD2 ligation and natural cytotoxicity receptors

Resting human NK cells require a two-stage activation process that we have previously described as "priming" and "triggering." NK-sensitive tumor cells provide both priming and triggering signals. NK-resistant tumors evade lysis, mostly by failure to prime; however, we recently reported a tumor cell line (CTV-1) that primes resting NK cells but fails to trigger lysis. In this article, we report two additional leukemia cell lines that prime NK cells but are resistant to lysis. Tumor-mediated NK priming is via CD2 binding to a ligand within CD15 on the tumor cell. NK-resistant RAJI cells became susceptible to NK lysis following transfection and expression of CD15. Blockade of CD15 on K562 cells or on CD15(+) RAJI cells significantly inhibited lysis, as did blockade of CD2 on resting NK cells. NK priming via CD2 induced CD16 shedding, releasing CD3ζ to the CD2, leading to its phosphorylation and the subsequent phosphorylation of linker for activation of T cells and STAT-5 and synthesis of IFN-γ. Blockade of C-type lectin receptors significantly suppressed the tumor-mediated priming of NK cells, whereas blockade of Ig-superfamily-like receptors had no effect at the NK-priming stage. Tumor priming of resting NK cells was irrespective of HLA expression, and blockade of HLA-killer Ig-like receptor interactions did not influence the incidence or degree of priming. However, CD15-CD2 interactions were critical for NK priming and were required, even in the absence of HLA-mediated NK inhibition. Tumor-mediated priming led to a sustained primed state, and the activated NK cells retained the ability to lyse NK-resistant tumors, even after cryopreservation.

[Effect of forest therapy on the human psycho-neuro-endocrino-immune network]

Traditional thinking considered the nervous system, endocrine system and immune system to be independent of each other. However, it is now widely accepted that these systems interact through the psycho-neuro-endocrino-immune network. The nervous system affects the endocrine and immune systems by releasing neurotransmitters through the hypothalamus in the hypothalamic-pituitary portal circulation. The endocrine system affects the nervous and immune systems by secreting hormones and the immune system feeds back to the nervous and endocrine systems via cytokines. Forest therapy reduces sympathetic nervous activity, increases parasympathetic nervous activity, and regulates the balance of autonomic nerves. As a result, forest therapy decreases blood pressure and heart rate and has a relaxing effect. Forest therapy affects psychological responses via the brain and nervous system thereby decreasing the scores for anxiety, depression, anger, fatigue, and confusion, and increasing the score for vigor in the POMS test. Forest therapy acts on the endocrine system to reduce stress hormone levels such as urinary adrenaline, urinary noradrenaline, salivary cortisol, and blood cortisol levels and shows a relaxing effect. Forest therapy also acts directly and indirectly on the immune system to promote NK activity by increasing the number of NK cells and intracellular levels of anticancer proteins such as perforin, granulysin and granzymes. Taken together, forest therapy brings various effects on human health via the psycho-neuro-endocrino-immune network.

Transcript signature predicts tissue NK cell content and defines renal cell carcinoma subgroups independent of TNM staging

Clear cell renal cell carcinoma (ccRCC) is an aggressive and difficult to manage cancer. Immunotherapy has the potential to induce long-lasting regression in a small group of patients. However, severe side effects limit broad application which highlights the need for a marker to distinguish responder from nonresponder. TNMG staging, referring to tumor size, lymph node involvement, presence of metastasis, and grade of tumor differentiation, represents an important prognostic system but is not useful for predicting responders to immunotherapy. NK cells are potent antitumor effector cells, and a role as prognostic marker in some solid tumors has been suggested. As NK cells are responsive to various immune modifiers, they may be important mediators of patient response to immunotherapies, in particular those including IL-2. We report that the NK cell percentage within RCC-infiltrating lymphocytes, as determined by flow cytometry, allows ccRCC subgrouping in NK(high)/NK(low) tissues independent of TNMG classification. Quantitative reverse transcriptase polymerase chain reaction using whole-tissue RNA identified four markers (NKp46, perforin, CX(3)CL1, and CX(3)CR1) whose transcript levels reproduced the NK(high)/NK(low) tissue distinction identified by flow cytometry with high selectivity and specificity. Combined in a multiplex profile and analyzed using neural network, the accuracy of predicting the NK(high)/NK(low) groups was 87.8%, surpassing that of each single marker. The tissue transcript signature, based on a robust high-throughput methodology, is easily amenable to archive material and clinical translation. This now allows the analysis of large patient cohorts to substantiate a role of NK cells in cancer progression or response to immunotherapy.

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.

Profound coordinated alterations of intratumoral NK cell phenotype and function in lung carcinoma

Both the innate and adaptive immune systems contribute to tumor immunosurveillance in mice and humans; however, there is a paucity of direct evidence of a role for natural killer (NK) cells in this important process. In this study, we investigated the intratumoral phenotypic profile and functions of NK cells in primary human tumor specimens of non-small cell lung carcinoma (NSCLC). We used in situ methods to quantify and localize NK cells using the NKp46 marker and we characterized their phenotype in blood, tumoral, and nontumoral samples of NSCLC patients. Intratumoral NK cells displayed a profound and coordinated alteration of their phenotype, with a drastic reduction of NK cell receptor expression specifically detected in the tumoral region. According to their altered phenotype, intratumoral NK cells exhibited profound defects in the ability to activate degranulation and IFN-γ production. We found that the presence of NK cells did not impact the clinical outcome of patients with NSCLC. Finally, we showed that tumor cells heterogeneously express ligands for both activating and inhibitory NK receptors. Taken together, our results suggest that the NSCLC tumor microenvironment locally impairs NK cells, rendering them less tumorcidal and thereby supportive to cancer progression.

Nasal lavage natural killer cell function is suppressed in smokers after live attenuated influenza virus

Background

Modified function of immune cells in nasal secretions may play a role in the enhanced susceptibility to respiratory viruses that is seen in smokers. Innate immune cells in nasal secretions have largely been characterized by cellular differentials using morphologic criteria alone, which have successfully identified neutrophils as a significant cell population within nasal lavage fluid (NLF) cells. However, flow cytometry may be a superior method to fully characterize NLF immune cells. We therefore characterized immune cells in NLF by flow cytometry, determined the effects of live attenuated influenza virus (LAIV) on NLF and peripheral blood immune cells, and compared responses in samples obtained from smokers and nonsmokers.

Methods

In a prospective observational study, we characterized immune cells in NLF of nonsmokers at baseline using flow cytometry and immunohistochemistry. Nonsmokers and smokers were inoculated with LAIV on day 0 and serial nasal lavages were collected on days 1-4 and day 9 post-LAIV. LAIV-induced changes of NLF cells were characterized using flow cytometry. Cell-free NLF was analyzed for immune mediators by bioassay. Peripheral blood natural killer (NK) cells from nonsmokers and smokers at baseline were stimulated in vitro with LAIV followed by flow cytometric and mediator analyses.

Results

CD45(+)CD56(-)CD16(+) neutrophils and CD45(+)CD56(+) NK cells comprised median 4.62% (range 0.33-14.52) and 23.27% (18.29-33.97), respectively, of non-squamous NLF cells in nonsmokers at baseline. LAIV did not induce changes in total NK cell or neutrophil percentages in either nonsmokers or smokers. Following LAIV inoculation, CD16(+) NK cell percentages and granzyme B levels increased in nonsmokers, and these effects were suppressed in smokers. LAIV inoculation enhanced expression of activating receptor NKG2D and chemokine receptor CXCR3 on peripheral blood NK cells from both nonsmokers and smokers in vitro but did not induce changes in CD16(+) NK cells or granzyme B activity in either group.

Conclusions

These data are the first to identify NK cells as a major immune cell type in the NLF cell population and demonstrate that mucosal NK cell cytotoxic function is suppressed in smokers following LAIV. Altered NK cell function in smokers suggests a potential mechanism that may enhance susceptibility to respiratory viruses.

NKG2D gene polymorphism has a significant impact on transplant outcomes after HLA-fully-matched unrelated bone marrow transplantation for standard risk hematologic malignancies

BACKGROUND

NKG2D, an activating and co-stimulatory receptor expressed on natural killer cells and T cells, plays pivotal roles in immunity to microbial infections as well as in cancer immunosurveillance. This study examined the impact of donor and recipient polymorphisms in the NKG2D gene on the clinical outcomes of patients undergoing allogeneic T-cell-replete myeloablative bone marrow transplantation using an HLA-matched unrelated donor.

DESIGN AND METHODS

The NKG2D polymorphism was retrospectively analyzed in a total 145 recipients with hematologic malignancies and their unrelated donors. The patients underwent transplantation following myeloablative conditioning; the recipients and donors were matched through the Japan Marrow Donor Program.

RESULTS

In patients with standard-risk disease, the donor NKG2D-HNK1 haplotype, a haplotype expected to induce greater natural killer cell activity, was associated with significantly improved overall survival (adjusted hazard ratio, 0.44; 95% confidence interval, 0.23 to 0.85; p=0.01) as well as transplant related mortality (adjusted hazard ratio, 0.42; 95% confidence interval, 0.21 to 0.86; p=0.02), but had no impact on disease relapse or the development of grade II-IV acute graft-versus-host disease or chronic graft-versus-host disease. The NKG2D polymorphism did not significantly influence the transplant outcomes in patients with high-risk disease.

CONCLUSIONS

These data suggest an association between the donor HNK1 haplotype and better clinical outcome among recipients, with standard-risk disease, of bone marrow transplants from HLA-matched unrelated donors.

Use of NK cell activity in cure by transplant

Analogous to T cells, Natural Killer (NK) cells may facilitate engraftment, combat infection, and control cancer in bone marrow or haematopoietic stem cell transplantation (HSCT); however, NK cells do not cause graft-versus-host disease. Killer immunoglobulin-like receptors (KIRs) regulate NK cell function, and recent data suggest that KIR is as important as its ligand (human leucocyte antigen; HLA) in HSCT for both malignant and non-malignant conditions. Because there is substantial variability in KIR gene content, allelic polymorphism, and cell-surface expression among people, careful selection of donors based on HLA and KIR is essential to optimize HSCT outcomes. Furthermore, NK cells may be used for adoptive immunotherapy after HSCT in place of conventional donor lymphocyte infusion, as part of pre-transplant cytoreductive therapy, or as an independent therapeutic agent in high-risk leukaemia in place of sibling donor HSCT.

Novel innate cancer killing activity in humans

Background

In this study, we pilot tested an in vitro assay of cancer killing activity (CKA) in circulating leukocytes of 22 cancer cases and 25 healthy controls.

Methods

Using a human cervical cancer cell line, HeLa, as target cells, we compared the CKA in circulating leukocytes, as effector cells, of cancer cases and controls. The CKA was normalized as percentages of total target cells during selected periods of incubation time and at selected effector/target cell ratios in comparison to no-effector-cell controls.

Results

Our results showed that CKA similar to that of our previous study of SR/CR mice was present in human circulating leukocytes but at profoundly different levels in individuals. Overall, males have a significantly higher CKA than females. The CKA levels in cancer cases were lower than that in healthy controls (mean ± SD: 36.97 ± 21.39 vs. 46.28 ± 27.22). Below-median CKA was significantly associated with case status (odds ratio = 4.36; 95% Confidence Interval = 1.06, 17.88) after adjustment of gender and race.

Conclusions

In freshly isolated human leukocytes, we were able to detect an apparent CKA in a similar manner to that of cancer-resistant SR/CR mice. The finding of CKA at lower levels in cancer patients suggests the possibility that it may be of a consequence of genetic, physiological, or pathological conditions, pending future studies with larger sample size.

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.

Probiotic Lactobacillus casei Shirota supplementation does not modulate immunity in healthy men with reduced natural killer cell activity

Oral intake of probiotic bacteria may beneficially modulate functions of NK cells. In healthy individuals, contradictory results exist as to whether NK cell functions can be modulated by probiotic bacteria. Therefore, the primary objective of our randomized, double-blind, placebo-controlled trial was to determine the effects of the probiotic strain Lactobacillus casei Shirota (LcS) on the activity of NK cells in healthy men who had been preselected for a reduced lytic function of their NK cells. Study participants (n = 68) were supplemented for 4 wk with a probiotic drink providing 1.95 × 10(10) CFU LcS/d or with a similar milk drink without probiotic additive. A run-in period of 2 wk preceded the probiotic supplementation followed by a 2-wk follow-up phase without the probiotic or control drink. Changes in the relative proportions of NK cells and other leukocytes as well as multiple functional measurements were determined longitudinally at baseline, after the 4-wk supplementation, and at the end of the follow-up. The probiotic supplementation had no significant effect on NK cell numbers and function or on phagocytosis, respiratory burst, or cytokine secretion of peripheral blood mononuclear cells. In conclusion, 4 wk of supplementation with LcS does not increase NK cell activity in healthy men with a reduced NK cell lytic activity. However, other doses of LcS, time of intervention, or differences, e.g. in the background diet, may result in a different outcome.

HLA antigen and NK cell activating ligand expression in malignant cells: a story of loss or acquisition

Malignant transformation of cells is often associated with changes in classical and non-classical HLA class I antigen, HLA class II antigen as well as NK cell activating ligand (NKCAL) expression. These changes are believed to play a role in the clinical course of the disease since these molecules are critical to the interactions between tumor cells and components of both innate and adaptive immune system. For some time, it has been assumed that alterations in the expression profile of HLA antigens and NKCAL on malignant cells represented loss of classical HLA class I antigen and induction of HLA class II antigen, non-classical HLA class I antigen and/or NKCAL expression. In contrast to these assumptions, experimental evidence suggests that in some cases dysplastic and malignant cells can acquire classical HLA class I antigen expression and/or lose the ability to express HLA class II antigens. In light of the latter findings as well as of the revival of the cancer immune surveillance theory, a reevaluation of the interpretation of changes in HLA antigen and NKCAL expression in malignant lesions is warranted. In this article, we first briefly describe the conventional types of changes in HLA antigen and NKCAL expression that have been identified in malignant cells to date. Second, we discuss the evidence indicating that, in at least some cell types, classical HLA class I antigen expression can be acquired and/or the ability to express HLA class II antigens is lost. Third, we review the available evidence for the role of immune selective pressure in the generation of malignant lesions with changes in HLA antigen expression. This information contributes to our understanding of the role of the immune system in the control of tumor development and to the optimization of the design of immunotherapeutic strategies for the treatment of cancer.

Natural killer cells in human cancer: from biological functions to clinical applications

Natural killer (NK) cells are central components of the innate immunity. In murine models, it has been shown that NK cells can control both local tumor growth and metastasis due to their ability to exert direct cellular cytotoxicity without prior sensitization and to secrete immunostimulatory cytokines like IFN-γ. The latter participates in cancer elimination by inhibiting cellular proliferation and angiogenesis, promoting apoptosis, and stimulating the adaptive immune system, and it is instrumental for enhancing Ag processing and presentation. Nevertheless, NK cells display impaired functionality and capability to infiltrate tumors in cancer patients. Also, NK cells are feasible targets of stimulation to participate in immunotherapeutic approaches like antibody-based strategies and adoptive cell transfer. Thus, multiple attempts currently aim to manipulate NK for utilization in the immunotherapy of cancer.

Dendritic cell based tumor vaccination in prostate and renal cell cancer: a systematic review and meta-analysis

BACKGROUND

More than 200 clinical trials have been performed using dendritic cells (DC) as cellular adjuvants in cancer. Yet the key question whether there is a link between immune and clinical response remains unanswered. Prostate and renal cell cancer (RCC) have been extensively studied for DC-based immunotherapeutic interventions and were therefore chosen to address the above question by means of a systematic review and meta-analysis.

METHODOLOGY/PRINCIPAL FINDINGS

Data was obtained after a systematic literature search from clinical trials that enrolled at least 6 patients. Individual patient data meta-analysis was performed by means of conditional logistic regression grouped by study. Twenty nine trials involving a total of 906 patients were identified in prostate cancer (17) and RCC (12). Objective response rates were 7.7% in prostate cancer and 12.7% in RCC. The combined percentages of objective responses and stable diseases (SD) amounted to a clinical benefit rate (CBR) of 54% in prostate cancer and 48% in RCC. Meta-analysis of individual patient data (n = 403) revealed the cellular immune response to have a significant influence on CBR, both in prostate cancer (OR 10.6, 95% CI 2.5-44.1) and in RCC (OR 8.4, 95% CI 1.3-53.0). Furthermore, DC dose was found to have a significant influence on CBR in both entities. Finally, for the larger cohort of prostate cancer patients, an influence of DC maturity and DC subtype (density enriched versus monocyte derived DC) as well as access to draining lymph nodes on clinical outcome could be demonstrated.

CONCLUSIONS/SIGNIFICANCE

As a 'proof of principle' a statistically significant effect of DC-mediated cellular immune response and of DC dose on CBR could be demonstrated. Further findings concerning vaccine composition, quality control, and the effect of DC maturation status are relevant for the immunological development of DC-based vaccines.

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.

Evaluation of human natural killer cell activities in whole blood

Natural killer (NK) cells are important effector cells of the innate immune system. Activation of NK cells results in their cytotoxic activity against locally attached target cells and leads to the secretion of cytokines. These activities are usually measured in purified NK cells or isolated peripheral blood mononuclear cells. In this unit, we describe a protocol to measure NK cell cytotoxicity (lysis of (51)Cr labeled target cells), degranulation (externalization of CD107a), and cytokine production (intracellular FACS analysis of IFN-γ) in whole-blood samples. Using these protocols, it is possible to perform a comprehensive analysis of NK cell function with as little as 3.5 ml of heparinized whole blood.

Immune response in ovarian cancer: how is the immune system involved in prognosis and therapy: potential for treatment utilization

Ovarian cancer is one of the leading causes of cancer-related death among women. Resistance to the disease occurs in more than 70% of the cases even after treated with chemotherapy agents such as paclitaxel- and platinum-based agents. The immune system is increasingly becoming a target for intense research in order to study the host's immune response against ovarian cancer. T cell populations, including NK T cells and Tregs, and cytokines have been associated with disease outcome, indicating their increasing clinical significance, having been associated with prognosis and as markers of disease progress, respectively. Harnessing the immune system capacity in order to induce antitumor response remains a major challenge. This paper examines the recent developments in our understanding of the mechanisms of development of the immune response in ovarian cancer as well as its prognostic significance and the existing experience in clinical studies.

Novel role for STAT3 in transcriptional regulation of NK immune cell targeting receptor MICA on cancer cells

The role of natural killer group 2, member D receptor (NKG2D)-expressing natural killer (NK) cells in tumor immunosurveillance is now well established. Nevertheless, tumor progression occurs despite tumor immunosurveillance, leading to cancer persistence in immunocompetent hosts. STAT3 plays a pivotal role both in oncogenic functions and in immunosuppression. In this study, we investigated the role of STAT3 in suppressing NK cell-mediated immunosurveillance. Using a colorectal cancer cell line (HT29) that can poorly activate NK, we neutralized STAT3 with pharmacologic inhibitors or siRNA and found that this led to an increase in NK degranulation and IFN-γ production in a TGF-β1-independent manner. Exposure to NKG2D-neutralizing antibodies partially restored STAT3 activity, suggesting that it prevented NKG2D-mediated NK cell activation. On this basis, we investigated the expression of NKG2D ligands after STAT3 activation in HT29, mesenchymal stem cells, and activated lymphocytes. The NK cell recognition receptor MHC class I chain-related protein A (MICA) was upregulated following STAT3 neutralization, and a direct interaction between STAT3 and the MICA promoter was identified. Because cross-talk between DNA damage repair and NKG2D ligand expression has been shown, we assessed the influence of STAT3 on MICA expression under conditions of genotoxic stress. We found that STAT3 negatively regulated MICA expression after irradiation or heat shock, including in lymphocytes activated by CD3/CD28 ligation. Together, our findings reveal a novel role for STAT3 in NK cell immunosurveillance by modulating the MICA expression in cancer cells.

Innate or adaptive immunity? The example of natural killer cells

Natural killer (NK) cells were originally defined as effector lymphocytes of innate immunity endowed with constitutive cytolytic functions. More recently, a more nuanced view of NK cells has emerged. NK cells are now recognized to express a repertoire of activating and inhibitory receptors that is calibrated to ensure self-tolerance while allowing efficacy against assaults such as viral infection and tumor development. Moreover, NK cells do not react in an invariant manner but rather adapt to their environment. Finally, recent studies have unveiled that NK cells can also mount a form of antigen-specific immunologic memory. NK cells thus exert sophisticated biological functions that are attributes of both innate and adaptive immunity, blurring the functional borders between these two arms of the immune response.

Fine particulate matter (PM₂.₅) air pollution and immune status among women in the Seattle area

Changes in immune status have been suggested as a possible biologic mechanism by which particulate matter (PM) air pollution could lead to adverse health effects. The authors studied associations between ambient PM₂.₅ and immune status among 115 postmenopausal, overweight women in the greater Seattle, Washington, area. The authors evaluated 3-day, 30-day, and 60-day average PM₂.₅ values in relation to inflammation markers (C-reactive protein, serum amyloid A, interleukin-6) and functional assays of cellular immunity (natural killer cell cytotoxicity, T-lymphocyte proliferation) at 3 time points for each woman during 1 year. Three-day averaged PM₂.₅ was inversely associated with anti-CD3-stimulated lymphocyte proliferation. There were no notable associations between the inflammation markers and PM₂.₅. If additional studies confirm our findings, then future health effect assessments for PM₂.₅ should consider changes in cellular immunity as an endpoint that may lead to overt clinical disease.

Pre-operative intracellular glutathione levels of peripheral monocytes as a biomarker to predict survival of colorectal cancer patients

The ability to predict anti-tumor immune responses at local tumor growing sites using only peripheral blood specimens would be helpful in determining therapeutic options for patients with solid tumors. Here, we show that the glutathione intracellular content (icGSH) of peripheral monocytes (Mo) correlates positively with T cell infiltration within tumor islets and overall survival in patients with colorectal carcinoma. IcGSH redox status was determined in CD14(+) Mo prior to surgery by staining with monochlorobimane. The tumor-infiltrating T cells (TIL) were quantified as CD45RO(+) T cells in resected tumors using paraffin sections. A positive association was found between the GSH index and TIL in tumor islets (P < 0.001). The 50% cut-off value for the GSH index, that is the determinant between TIL presence or absence in tumor islets, was calculated to be almost 0.7 through logistic regression analysis. Mo with a GSH index of > or =0.7 were termed reductive (R)-Mo, and those with <0.7 were designated as oxidative (O)-Mo. Cox's proportional hazards regression analysis of patients with R-Mo or O-Mo prior to surgery, and the presence or absence of TIL, was found to correlate significantly with the overall survival rate of stage II and III patients. Kaplan-Meier analysis also showed a significant correlation. These results indicate that the Mo icGSH index is a useful biomarker parameter for better understanding the host/tumor relationship prior to surgery, thereby enabling the development of an individual patient-oriented therapeutic strategy.

Nurses, smoking, and immunity: a review

Nurses regularly are exposed to a variety of occupational hazards. In addition to documented occupational hazards, exposure to smoking remains a major concern. This article reviews the prevalence of smoking among nurses working in the United States and discusses their reasons for smoking. Researchers conducted a state-of-the-art review on the effects of cigarette smoking and exposure to secondhand smoke (SHS) on the immune system. Smoking prevalence among nurses working in the United States ranged from 796-12%, and high work stress, poor work environment, shift work, and peer influence were suspected major risk factors influencing smoking behavior. A review of the effects of smoking on immunity revealed that both active smoking and exposure to SHS negatively affects immune function. When rehabilitation nurses stop smoking their health improves and nonsmokers are exposed to less SHS. Rehabilitation nurses are encouraged to share knowledge of the immunological benefits of smoking cessation with patients to facilitate nurse-led rehabilitation programs.

New views on natural killer cell-based immunotherapy for melanoma treatment

Natural killer (NK) cell-based immunotherapies treat hematopoietic malignancies, but are less effective against solid tumors. Here, we review recent data on NK cell recognition of melanoma at various stages of the disease and propose a combinatorial strategy to exploit fully the potential of NK cells. Depending on the stage of melanoma progression, NK cell-based therapies could be combined with pharmacological and T cell-based immunotherapies, to: (i) prevent lymph node metastases by redistributing cytotoxic NK cells; (ii) boost NK cell activity using chemotherapy to upregulate activating ligands on tumor cells; and (iii) target visceral metastases by transfer of autologous or allogeneic NK cells.

Extracapsular spread in oral squamous cell carcinoma

BACKGROUND

Extracapsular spread (ECS) in the cervical lymph nodes represents the most significant adverse prognostic indicator in oral squamous cell carcinoma (OSCC).

METHODS

In a consecutive cohort of OSCC treated by primary surgery, ECS was seen in 25% (101) of 400 patients.

RESULTS

ECS doubled the incidence of local recurrence and distant metastases, but tripled regional failure. The recurrences occurred sooner in ECS than in non-ECS cases (206 vs 334 days, p = .04). Patients with macroscopic ECS had a 5-year overall survival (OS) of 19% compared with 31% in microscopic ECS. MRI neck staging offered poor sensitivity, especially in microscopic ECS. Age >75 years, smoking, and heavy use of alcohol were independent predictors of ECS, which may implicate a failure of immunosurveillance by the host as much as adverse biology of the tumor.

CONCLUSIONS

Reporting of ECS is essential in accurate prognostication, and we advocate that all patients with OSCC and ECS should be grouped as pN3 on the basis of their prognosis. (c) 2009 Wiley Periodicals, Inc. Head Neck, 2010.

Perforin: structure, function, and role in human immunopathology

The secretory granule-mediated cell death pathway is the key mechanism for elimination of virus-infected and transformed target cells by cytotoxic lymphocytes. The formation of the immunological synapse between an effector and a target cell leads to exocytic trafficking of the secretory granules and the release of their contents, which include pro-apoptotic serine proteases, granzymes, and pore-forming perforin into the synapse. There, perforin polymerizes and forms a transmembrane pore that allows the delivery of granzymes into the cytosol, where they initiate various apoptotic death pathways. Unlike relatively redundant individual granzymes, functional perforin is absolutely essential for cytotoxic lymphocyte function and immune regulation in the host. Nevertheless, perforin is still the least studied and understood cytotoxic molecule in the immune system. In this review, we discuss the current state of affairs in the perforin field: the protein's structure and function as well as its role in immune-mediated diseases.

Innate and adaptive immunosenescence

OBJECTIVE

To review the effect of increasing age on the immune system and some of its clinical implications.

DATA SOURCES

MEDLINE and PubMed searches were performed cross-referencing the keywords immunosenescence, aging, and immunity. Articles were reviewed for additional citations.

STUDY SELECTION

Articles were reviewed and selected based on relevance to subject matter.

RESULTS

The study of immunosenescence is complex and not completely understood. Aging affects both the innate and adaptive arms of the immune response. With increased age, there may be a decrease in phagocytosis, alteration of cellular migration, changes in cell populations and numbers, and a decreased ability to produce specific antibodies. Clinically, these changes potentially increase morbidity and mortality in elderly individuals through an increased rate of infections, malignancy, and autoimmunity.

CONCLUSIONS

The process of aging is accompanied by diverse changes in immunity. Several therapeutic approaches are under investigation, including cytokine therapy, hormonal replacement, antioxidant supplementation, and caloric restriction, to attenuate or potentially reverse immunosenescence.

[The role of chemotherapy in pediatric medulloblastoma]

Medulloblastoma is one of the most frequent brain tumors in childhood. The mortality of medulloblastoma decreased significantly during the last few decades, which was the result of the better surgical and radiotherapeutic methods and of the development of chemotherapy. The aim of this publication is the critical review of the present chemotherapeutic treatment. The new therapeutic trials based on the molecular genetic mechanism of these tumors are also mentioned.

Deficient innate immunity, thymopoiesis, and gene expression response to radiation in survivors of childhood acute lymphoblastic leukemia

BACKGROUND

Survivors of childhood acute lymphoblastic leukemia (ALL) are at an increased risk of developing secondary malignant neoplasms. Radiation and chemotherapy can cause mutations and cytogenetic abnormalities and induce genomic instability. Host immunity and appropriate DNA damage responses are critical inhibitors of carcinogenesis. Therefore, we sought to determine the long-term effects of ALL treatment on immune function and response to DNA damage.

METHODS

Comparative studies on 14 survivors in first complete remission and 16 siblings were conducted.

RESULTS

In comparison to siblings on the cells that were involved in adaptive immunity, the patients had either higher numbers (CD19+ B cells and CD4+CD25+ T regulatory cells) or similar numbers (alphabetaT cells and CD45RO+/RA- memory T cells) in the blood. In contrast, patients had lower numbers of all lymphocyte subsets involved in innate immunity (gammadeltaT cells and all NK subsets, including KIR2DL1+ cells, KIR2DL2/L3+ cells, and CD16+ cells), and lower natural cytotoxicity against K562 leukemia cells. Thymopoiesis was lower in patients, as demonstrated by less CD45RO-/RA+ naïve T cell and less SjTREC levels in the blood, whereas the Vbeta spectratype complexity score was similar. Array of gene expression response to low-dose radiation showed that about 70% of the probesets had a reduced response in patients. One of these genes, SCHIP-1, was also among the top-ranked single nucleotide polymorphisms (SNPs) during the whole-genome scanning by SNP microarray analysis.

CONCLUSION

ALL survivors were deficient in innate immunity, thymopoiesis, and DNA damage responses to radiation. These defects may contribute to their increased likelihood of second malignancy.

NK cells and gammadelta T cells mediate resistance to polyomavirus-induced tumors

NK and γδ T cells can eliminate tumor cells in many experimental models, but their effect on the development of tumors caused by virus infections in vivo is not known. Polyomavirus (PyV) induces tumors in neonatally infected mice of susceptible strains and in adult mice with certain immune deficiencies, and CD8+ αβ T cells are regarded as the main effectors in anti-tumor immunity. Here we report that adult TCRβ knockout (KO) mice that lack αβ but have γδ T cells remain tumor-free after PyV infection, whereas TCRβ×δ KO mice that lack all T cells develop tumors. In addition, E26 mice, which lack NK and T cells, develop the tumors earlier than TCRβ×δ KO mice. These observations implicate γδ T and NK cells in the resistance to PyV-induced tumors. Cell lines established from PyV-induced tumors activate NK and γδ T cells both in culture and in vivo and express Rae-1, an NKG2D ligand. Moreover, these PyV tumor cells are killed by NK cells in vitro, and this cytotoxicity is prevented by treatment with NKG2D-blocking antibodies. Our findings demonstrate a protective role for NK and γδ T cells against naturally occurring virus-induced tumors and suggest the involvement of NKG2D-mediated mechanisms.

Virus-induced tumors account for a large fraction of malignancies in both humans and mice. These tumors express viral antigens and have been thought to be controlled mostly by αβ TCR+ CD8 T lymphocytes that are specific for viral peptides. We found that mice lacking αβ T cells are protected from the formation of tumors induced by the small DNA virus polyoma (PyV) if they have γδ T and NK cells. Moreover, cell lines we established from the virus-induced tumors induced NK and γδ T cell activation, and expressed Rae-1, a cellular stress molecule which serves as ligand for NKG2D, an activating receptor on NK and γδ T cells. NK and γδ T cells seemed to mount antitumor but not antiviral responses, as their presence did not change the amount of persisting virus significantly. Our studies suggest that mice have a multipronged host defense against PyV-induced tumors that includes γδ T and NK cells in addition to αβ T cell responses. Merkel cell virus, a tumor causing polyomavirus in humans, is closely related to PyV with a similar biology, making it very important to understand mechanisms involved in host control of tumor development in the course of these life-long persistent infections.

Probiotics and immunosenescence: cheese as a carrier

Oral intake of specific probiotics has been reported to enhance the immunity of the elderly. Earlier studies have used milk or yoghurt as a probiotic carrier. We chose a commercial probiotic cheese to evaluate its potential as a probiotic food. Thirty-one healthy elderly volunteers (21 female, 10 male) aged from 72 to 103 (median 86) consumed a commercial probiotic cheese containing approximately 10(9) CFU day(-1) of Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus NCFM. The 4-week probiotic intervention was preceded by a 2-week consumption of probiotic-free cheese (run-in) and followed by a 4-week wash-out period with the same control cheese. The cytotoxicity of peripheral blood mononuclear cells (PBMCs), the relative numbers of natural killer (NK) and NKT cells in the total PBMCs, and phagocytic activity were assessed. Consumption of the probiotic cheese significantly increased the cytotoxicity of NK cells. A significant increase in phagocytosis was observed for both the control and the probiotic cheese. Cheese was found to be an effective carrier for the study of probiotics, and daily consumption of the probiotic enhanced parameters of innate immunity in elderly volunteers. It remains to be determined whether this enhancement correlates with a beneficial effect on the health of the elderly population.

Immunotherapy in the context of hematopoietic stem cell transplantation: the emerging role of natural killer cells and mesenchymal stromal cells

Immunotherapy in the context of hematopoietic stem cell transplantation has been dominated for many years by T-cell- and dendritic-cell-based treatment modalities. During the last decade, insight into the biology of natural killer (NK) cells and mesenchymal stromal cells (MSC) has rapidly increased and resulted in NK- and MSC-based therapeutic strategies in clinical practice. This article reviews current knowledge of the biology and clinical aspects of NK cells and MSC.

Perforin deficiency and susceptibility to cancer

Cytotoxic lymphocytes (CLs) are the killer cells that destroy intracellular pathogen-infected and transformed cells, predominantly through the cytotoxic granule-mediated death pathway. Soluble cytotoxic granule components, including pore-forming perforin and pro-apoptotic serine proteases, granzymes, synergize to induce unscheduled apoptosis of the target cell. A complete loss of CL function results in an aggressive immunoregulatory disorder, familial hemophagocytic lymphohistiocytosis, whereas a partial loss of function seems to be a factor strongly predisposing to hematological malignancies. This review discusses the pathological manifestations of CL deficiencies due to impaired perforin function and describes novel aspects of perforin biology.

Development of functional human NK cells in an immunodeficient mouse model with the ability to provide protection against tumor challenge

Studies of human NK cells and their role in tumor suppression have largely been restricted to in vitro experiments which lack the complexity of whole organisms, or mouse models which differ significantly from humans. In this study we showed that, in contrast to C57BL/6 Rag2^−/−/γ_c^−/− and NOD/Scid mice, newborn BALB/c Rag2^−/−/γ_c^−/− mice can support the development of human NK cells and CD56+ T cells after intrahepatic injection with hematopoietic stem cells. The human CD56⁺ cells in BALB/c Rag2^−/−/γ_c^−/− mice were able to produce IFN-γ in response to human IL-15 and polyI:C. NK cells from reconstituted Rag2^−/−/γ_c^−/− mice were also able to kill and inhibit the growth of K562 cells in vitro and were able to produce IFN-γ in response to stimulation with K562 cells. In vivo, reconstituted Rag2^−/−/γ_c^−/− mice had higher survival rates after K562 challenge compared to non-reconstituted Rag2^−/−/γ_c^−/− mice and were able to control tumor burden in various organs. Reconstituted Rag2^−/−/γ_c^−/− mice represent a model in which functional human NK and CD56+ T cells can develop from stem cells and can thus be used to study human disease in a more clinically relevant environment.

Cytomegalovirus-induced gammadelta T cells associate with reduced cancer risk after kidney transplantation

An increase in the number of blood gammadelta T cells follows cytomegalovirus (CMV) infection in kidney transplant recipients. These cells react against CMV-infected cells and tumor epithelial cells in vitro. We hypothesized that these CMV-induced gammadelta T cells play a protective role against cancer in kidney transplant recipients. We performed a longitudinal case-control study involving 18 recipients who developed cancer between 2 and 6 yr after transplantation and 45 recipients who did not. The median percentage of gammadelta T cells among total lymphocytes in patients with malignancies was significantly lower compared with that in control patients at 6, 12, and 18 mo before the diagnosis of cancer. Patients with a gammadelta T cell percentage of more than 4% were protected from cancer. An increase of the Vdelta2(neg) gammadelta T cell subset significantly associated with lower incidence of cancer only in recipients who experienced pre- or postgraft CMV infection. Finally, a retrospective follow-up of 131 recipients for 8 yr revealed that CMV-naive recipients had an approximately 5-fold higher risk of cancer compared with CMV-exposed patients. In summary, these results suggest a protective role of CMV exposure against cancer in kidney transplant recipients.

Thymosin beta 4 enhances NK cell cytotoxicity mediated by ICAM-1

Thymosin beta 4 (T beta 4), which is the major G-actin sequestering protein, has been shown to have ubiquitous distribution and multiple biological activities. However, T beta 4's functions in relation to natural killer(NK) cells are still unknown. In this study, we show that synthetic T beta 4 peptide increases NK cell cytotoxicity mediated by intercellular adhesion molecule-1 (ICAM-1) through the secretion of cytolytic granules to target cells. This suggests that T beta 4 is a key activator of NK cell cytotoxicity.

Breast cancer lung metastasis requires expression of chemokine receptor CCR4 and regulatory T cells

Cancer metastasis is a leading cause of cancer morbidity and mortality. More needs to be learned about mechanisms that control this process. In particular, the role of chemokine receptors in metastasis remains controversial. Here, using a highly metastatic breast cancer (4T1) model, we show that lung metastasis is a feature of only a proportion of the tumor cells that express CCR4. Moreover, the primary tumor growing in mammary pads activates remotely the expression of TARC/CCL17 and MDC/CCL22 in the lungs. These chemokines acting through CCR4 attract both tumor and immune cells. However, CCR4-mediated chemotaxis was not sufficient to produce metastasis, as tumor cells in the lung were efficiently eliminated by natural killer (NK) cells. Lung metastasis required CCR4(+) regulatory T cells (Treg), which directly killed NK cells using beta-galactoside-binding protein. Thus, strategies that abrogate any part of this process should improve the outcome through activation of effector cells and prevention of tumor cell migration. We confirm this prediction by killing CCR4(+) cells through delivery of TARC-fused toxins or depleting Tregs and preventing lung metastasis.

The role of immunity in elderly cancer

The increased incidence of malignancies in elderly patients living in industrialized countries has led to both identify the causes that alter the normal homeostatic balance in elderly and designate the specific treatments. The progressive decline of the immune system (immunosenescence) involving cellular and molecular alterations impact both innate and adaptive immunity. The immunosenescence leads to increased incidence of infectious diseases morbidity and mortality as well as heightened rates of other immune disorders such as autoimmunity, cancer, and inflammatory conditions. Here, we summarize the knowledge on the major changes in the immune system associated with aging in primary lymphoid organs as well as a description of molecular mechanisms, and the impact on cancer development.

KIR-HLA receptor-ligand mismatch associated with a graft-versus-tumor effect in haploidentical stem cell transplantation for pediatric metastatic solid tumors

Killer immunoglobulin-like receptors (KIRs) on natural killer cells (NKs) recognize groups of human leukocyte antigen (HLA) class I alleles. Cells without an inhibitory HLA ligand may trigger NK activation. Reduced risk of relapse has been reported in malignant hematologic diseases after haploidentical transplantation when HLA ligands against the inhibitory KIRs present in the donor were absent in the recipient. We performed haploidentical transplant in three children with refractory solid tumors. Our results showed that beneficial antitumor effects could be observed in the presence of inhibitory KIR-HLA mismatch. These preliminary results suggest a possible association between disease control and NK cell alloreactivity.

ERK5 knockdown generates mouse leukemia cells with low MHC class I levels that activate NK cells and block tumorigenesis

Tumor cell-based vaccines are currently used in clinical trails, but they are in general poorly immunogenic because they are composed of cell extracts or apoptotic cells. Live tumor cells should be much better Ags provided that they are properly processed by the host immune system. We show herein that stable expression of a small hairpin RNA for ERK5 (shERK5) decreases ERK5 levels in human and mouse leukemic cells and leads to their elimination by NK cells in vivo. The shERK5 cells show down-regulation of MHC class I expression at the plasma membrane. Accordingly, ectopic activation of the ERK5 pathway induces MHC class I gene expression. Coinjection of shERK5-expressing cells into the peritoneum diminishes survival of engrafted wild-type tumor cells. Moreover, s.c. injection of shERK5-expressing cells strongly diminishes tumor development by wild-type cells. Our results show that shERK5 expression in leukemia cells effectively attenuates their tumor activity and allows their use as a tumor cell-based vaccine.