Modulation of tumor-infiltrating lymphocyte cytolytic activity against human non-small cell lung cancer

Myco-remediation of chromium heavy metal from industrial wastewater: A review

Chromium a heavy metal present in the effluent of the industries causes accumulation of toxicity in water. Chromium commonly has Cr (III) and Cr (VI), two oxidation states, in which hexavalent form causes more health issues to human, other species and environment. The increased anthropogenic effects, especially tannery industrial effluent contributes the higher percentage of chromium accumulation. Removal of heavy metal can be attributed to many aspects, conventionally the physio-chemical methods which superseded by biological means of remediation. Chromium resistant microbes can be used to remove metal ions of chromium from the effluent, as this can be considered an eco-friendly approach. The microbial accession of nanoparticles synthesis is being focused, due to its accuracy and specificity in results. Mycoremediation grabbed attention as fungal absorbance efficiency and the surface-mechanism of heavy metal ions correlates each other. Current study in-depth indulges the base to core mechanism of mycoremediation of chromium ions from different effluents. Fungal-assisted mechanism of chromium ions have insists to be fewer, which may gain attention by enhancing the methodology of removal of chromium ions. This study focuses on improvement of fungal strain and pave-way, to improvise the study with immobilization technique which renders usage of the adsorbents redundant usage and applications, substantially with the low-cost polymeric material alginate is given more importance for immobilization technique. Alginate apart from low-cost adsorbent, is an excellent support for fungal producing nanoparticles which would provide wide-cast and an extraordinary adsorbent material.

Immunosuppressive Phenotype of Esophagus Tumors Stroma

Background

Tumor-associated macrophages (TAMs) and tumor-infiltrating lymphocytes (TILs) contribute significantly to the development of immunosuppressive properties of a tumor. In this study, we performed immunohistochemical analysis of immune cells of esophageal tumors stroma.

Methods

Paraffin-embedded tissue specimens from 48 esophageal squamous cell carcinoma (ESCC) patients were retrospectively collected for immunohistochemical analysis of stromal cells. For staining of macrophages, CD68, CD163, CD206, PU.1, and iNOS were used. For T cell detection, CD8, CD3, and FOXP3 were used. Also, we performed staining for PD-L1 that can be expressed on TAMs and tumor cells. Clinicopathological and survival data were collected and analyzed using the χ² and Fisher exact tests, Kaplan–Meier curves, and the log-rank test. The correlation analysis was performed with Spearman's rank correlation coefficient.

Results

We found that FOXP3 expression was associated with age (p = 0.042) and iNOS expression was associated with the disease stage (p = 0.044). In addition, FOXP3 and CD163 appeared to be markers of good prognosis (HR = 0.4420, p = 0.0325, and HR = 0.4447, p = 0.0456, respectively). Significant association between PU.1+ and CD68+ macrophages (r = 0.833; p ≤ 0.001) and between PU.1+ and CD163+ macrophages (r = 0.500; p ≤ 0.001) was established; positive association between PU.1 and CD206 expression was also observed (r = 0.250; p = 0.043).

Conclusions

Large amounts of CD163+ macrophages and FOXP3+ Т cells appear to be markers of good prognosis of ESCC. The number of PU.1+ macrophages strongly correlates with the number of CD68+ macrophages; therefore, usage of PU.1 as a potential macrophage marker can be recommended for esophageal tumors.

Kras and Tumor Immunity: Friend or Foe?

With the recent breakthroughs in immunotherapy as curative treatments in certain tumor types, there has been renewed interest in the relationship between immunity and tumor growth. Although we are gaining a greater understanding of the complex interplay of immune modulating components in the tumor microenvironment, the specific role that tumor cells play in shaping the immune milieu is still not well characterized. In this review, we focus on how mutant Kras tumor cells contribute to tumor immunity, with a specific focus on processes induced directly or indirectly by the oncogene.

Pro-tumor activities of macrophages in the progression of melanoma

Macrophages are located in essentially all tissues due to their “janitor” function. Macrophages can exert either anti- or pro-tumor activities depending upon the specific tumor microenvironment they inhabit. Substantial evidence indicates that macrophages, owing to their plasticity, can be reeducated to adopt a protumoral phenotype within a tumor microenvironment through the help of growth factors in the microenvironment and intercellular interactions. As the lethality of malignant melanoma is due to its aggressive capacity for metastasis and resistance to therapy, considerable effort has gone toward treatment of metastatic melanoma. In the present review, we focus on the pro-tumor activities of macrophages in melanoma. Based upon the information presented in this review it is anticipated that new therapies will soon be developed that target pro-tumor activities of macrophages for use in the treatment of melanoma.

Radiation-induced lung fibrosis in a tumor-bearing mouse model is associated with enhanced Type-2 immunity

Lung fibrosis may be associated with Type-2 polarized inflammation. Herein, we aim to investigate whether radiation can initiate a Type-2 immune response and contribute to the progression of pulmonary fibrosis in tumor-bearing animals. We developed a tumor-bearing mouse model with Lewis lung cancer to receive either radiation therapy alone or radiation combined with Th1 immunomodulator unmethylated cytosine-phosphorothioate-guanine containing oligodeoxynucleotide (CpG-ODN). The Type-2 immune phenotype in tumors and the histological grade of lung fibrosis were evaluated in mice sacrificed three weeks after irradiation. Mouse lung tissues were analyzed for hydroxyproline and the expression of Type-1/Type-2 key transcription factors (T-bet/GATA-3). The concentration of Type-1/Type-2 cytokines in serum was measured by cytometric bead array. Lung fibrosis was observed to be more serious in tumor-bearing mice than in normal mice post-irradiation. The fibrosis score in irradiated tumor-bearing mice on Day 21 was 4.33 ± 0.82, which was higher than that of normal mice (2.00 ± 0.63; P < 0.05). Hydroxyproline and GATA-3 expression were increased in the lung tissues of tumor-bearing mice following irradiation. CpG-ODN attenuated fibrosis by markedly decreasing GATA-3 expression. Serum IL-13 and IL-5 were elevated, whereas INF-γ and IL-12 expression were decreased in irradiated tumor-bearing mice. These changes were reversed after CpG-ODN treatment. Thus, Type-2 immunity in tumors appeared to affect the outcome of radiation damage and might be of interest for future studies on developing approaches in which Type-1-related immunotherapy and radiotherapy are used in combination.

Novel antigens in non-small cell lung cancer: SP17, AKAP4, and PTTG1 are potential immunotherapeutic targets

Lung cancer is the leading cause of cancer deaths in both genders worldwide, with an incidence only second to prostate cancer in men and breast cancer in women. The lethality of the disease highlights the urgent need for innovative therapeutic options. Immunotherapy can afford efficient and specific targeting of tumor cells, improving efficacy and reducing the side effects of current therapies. We have previously reported the aberrant expression of cancer/testis antigens (CTAs) in tumors of unrelated histological origin. In this study we investigated the expression and immunogenicity of the CTAs, Sperm Protein 17 (SP17), A-kinase anchor protein 4 (AKAP4) and Pituitary Tumor Transforming Gene 1 (PTTG1) in human non-small cell lung cancer (NSCLC) cell lines and primary tumors. We found that SP17, AKAP4 and PTTG1 are aberrantly expressed in cancer samples, compared to normal lung cell lines and tissues. We established the immunogenicity of these CTAs by measuring CTA-specific autoantibodies in patients' sera and generating CTA-specific autologous cytotoxic lymphocytes from patients' peripheral blood mononuclear cells. Our results provide proof of principle that the CTAs SP17/AKAP4/PTTG1 are expressed in both human NSCLC cell lines and primary tumors and can elicit an immunogenic response in lung cancer patients.

Prognostic significance of tumor-infiltrating CD8⁺ or CD3⁺ T lymphocytes and interleukin-2 expression in radically resected non-small cell lung cancer

Background:

Altered immunoresponse is associated with tumorigenesis and cancer progression. This study assessed the levels of tumor-infiltrating CD3⁺ or CD8⁺ T lymphocytes and interleukin-2 (IL-2) protein in radically resected non-small cell lung cancer (NSCLC) tissues to predict overall survival (OS) of the patients.

Methods:

Paraffin-embedded tissue specimens from 129 NSCLC patients were retrospectively collected for immunostaining of CD8⁺, CD3⁺, and IL-2 expression. Clinicopathological and survival data were collected and analyzed using the Chi-squared test, Kaplan–Meier curves, and the log-rank test or the Cox regression model.

Results:

The data showed a significant inverse association between CD8⁺ T lymphocyte levels and IL-2 expression (r = −0.927; P = 0.000) and between the levels of CD8⁺ and CD3⁺ T lymphocytes (r = −0.722; P = 0.000), but a positive association between CD3⁺ T lymphocyte levels and IL-2 expression (r = 0.781; P = 0.000) in NSCLC tissues. Furthermore, the levels of CD3⁺ and CD8⁺ T lymphocytes and IL-2 expression were associated with tumor stage (P = 0.023, 0.006, and 0.031, respectively) and the level of CD8⁺ T lymphocytes was associated with the patient gender (P = 0.024). In addition, the levels of CD8⁺ T lymphocytes were associated with an unfavorable 5-year OS, whereas patients with high levels of CD3⁺ T lymphocytes in tumor lesions and IL-2-expressing tumors had significantly better 5-year OS rates than patients with low levels.

Conclusions:

The levels of CD8⁺ T cells in tumor lesions and IL-2 expression were both independent predictors of OS for these NSCLC patients. Thus, the detection of tumor-infiltrating CD3⁺ or CD8⁺ T lymphocytes and IL-2 expression could be useful to predict the prognosis of radically resected NSCLC patients.

Bioremediation of hexavalent chromium (VI) by a soil-borne bacterium, Enterobacter cloacae B2-DHA

Chromium and chromium containing compounds are discharged into the nature as waste from anthropogenic activities, such as industries, agriculture, forest farming, mining and metallurgy. Continued disposal of these compounds to the environment leads to development of various lethal diseases in both humans and animals. In this paper, we report a soil borne bacterium, B2-DHA that can be used as a vehicle to effectively remove chromium from the contaminated sources. B2-DHA is resistant to chromium with a MIC value of 1000 µg mL(-1) potassium chromate. The bacterium has been identified as a Gram negative, Enterobacter cloacae based on biochemical characteristics and 16S rRNA gene analysis. TOF-SIMS and ICP-MS analyses confirmed intracellular accumulation of chromium and thus its removal from the contaminated liquid medium. Chromium accumulation in cells was 320 µg/g of cells dry biomass after 120-h exposure, and thus it reduced the chromium concentration in the liquid medium by as much as 81%. Environmental scanning electron micrograph revealed the effect of metals on cellular morphology of the isolates. Altogether, our results indicate that B2-DHA has the potential to reduce chromium significantly to safe levels from the contaminated environments and suggest the potential use of this bacterium in reducing human exposure to chromium, hence avoiding poisoning.

Effects of reticuloendotheliosis virus infection on cytokine production in SPF chickens

Infection with reticuloendotheliosis virus (REV), a gammaretrovirus in the Retroviridae family, can result in immunosuppression and subsequent increased susceptibility to secondary infections. The effects of REV infection on expression of mRNA for cytokine genes in chickens have not been completely elucidated. In this study, using multiplex branched DNA (bDNA) technology, we identified molecular mediators that participated in the regulation of the immune response during REV infection in chickens. Cytokine and chemokine mRNA expression levels were evaluated in the peripheral blood mononuclear cells (PBMCs). Expression levels of interleukin (IL)-4, IL-10, IL-13 and tumor necrosis factor (TNF)-α were significantly up-regulated while interferon (IFN)-α, IFN-β, IFN-γ, IL-1β, IL-2, IL-3, IL-15, IL-17F, IL-18 and colony-stimulating factor (CSF)-1 were markedly decreased in PBMCs at all stages of infection. Compared with controls, REV infected chickens showed greater expression levels of IL-8 in PBMCs 21 and 28 days post infection. In addition, REV regulates host immunity as a suppressor of T cell proliferative responses. The results in this study will help us to understand the host immune response to virus pathogens.

TGF-beta specifically enhances the metastatic attributes of murine lung adenocarcinoma: implications for human non-small cell lung cancer

Lung cancer is the most frequent and one of the most deadly cancer types and is classified into small cell lung cancer and non-small cell lung cancer (NSCLC). Transforming growth factor beta (TGFβ) regulates a wide array of cell functions and plays a major role in lung diseases, including NSCLC. TGFβ signals through the complex of TGFβ type I and type II receptors, triggering Smad and non-Smad signaling pathways such as PI3K/Akt and MEK1/ERK. We investigated the role of TGFβ1 on the progression of the murine lung adenocarcinoma cell line LP07. Furthermore, we undertook a retrospective study with tissue samples from stage I and II NSCLC patients to assess the clinical pathologic role and prognostic significance of TβRI expression. We demonstrated that although lung cancer cell monolayers responded to TGFβ1 anti-mitogenic effects and TGFβ1 pulse (24 h treatment) delayed tumor growth at primary site; a switch towards malignant progression upon TGFβ1 treatment was observed at the metastatic site. In our model, TGFβ1 modulated in vitro clonogenicity, protected against stress-induced apoptosis and increased adhesion, spreading, lung retention and metastatic outgrowth. PI3K and MEK1 signaling pathways were involved in TGFβ1-mediated metastasis stimulation. Several of these TGFβ responses were also observed in human NSCLC cell lines. In addition, we found that a higher expression of TβRI in human lung tumors is associated with poor patient's overall survival by univariate analysis, while multivariate analysis did not reach statistical significance. Although additional detailed analysis of the endogenous signaling in vivo and in vitro is needed, these studies may provide novel molecular targets for the treatment of lung cancer.

The role of inflammation in the pathogenesis of non-small cell lung cancer

The link between chronic immune activation and tumorigenesis is well established. Compelling evidence has accumulated that histologic assessment of infiltration patterns of different host immune response components in non-small cell lung cancer specimens helps identify different prognostic patient subgroups. This review provides an overview of recent insights gained in the understanding of the role played by chronic inflammation in lung carcinogenesis. The usefulness of quantification of different populations of lymphocytes, natural killer cells, macrophages, and mast cells within the tumor microenvironment in non-small cell lung cancer is also discussed. In particular, the importance of assessment of inflammatory cell microlocalization within both the tumor islet and surrounding stromal components is emphasized.

Activation of a TGF-beta-specific multistep gene expression program in mature macrophages requires glucocorticoid-mediated surface expression of TGF-beta receptor II

Alternatively activated (M2) macrophages regulate steady state-, cancer-, and inflammation-related tissue remodeling. They are induced by Th2-cytokines and glucocorticoids (GC). The responsiveness of mature macrophages to TGF-beta, a cytokine involved in inflammation, cancer, and atherosclerosis, is currently controversial. Recently, we demonstrated that IL-17 receptor B is up-regulated in human monocyte-derived macrophages differentiated in the presence of Th2 cytokines IL-4 and TGF-beta1. In this study, we show that mature human macrophages differentiated in the presence of IL-4, and dexamethasone (M2(IL-4/GC)) but not M2(IL-4) responds to TGF-beta1 which induced a gene expression program comprising 111 genes including transcriptional/signaling regulators (ID3 and RGS1), immune modulators (ALOX5AP and IL-17 receptor B) and atherosclerosis-related genes (ALOX5AP, ORL1, APOC1, APOC2, and APOE). Analysis of molecular mechanism underlying GC/TGF-beta cooperation revealed that surface expression of TGF-betaRII was high in M2(GC) and M2(IL-4/GC), but absent from M2(IL-4), whereas the expression of TGF-betaRI/II mRNA, TGF-betaRII total protein, and surface expression of TGF-betaRIII were unchanged. GC dexamethasone was essential for increased surface expression of functional TGF-betaRII because its effect was observed also in combination with IL-13, M-CSF, and GM-CSF. Prolonged Smad2-mediated signaling observed in TGF-beta1-treated M2(IL-4/GC) was due to insufficient activity of negative feedback mechanism what can be explained by up-regulation of SIRT1, a negative regulator of Smad7, and the retention of TGF-betaRII complex on the cell surface. In summary, mature human M2 macrophages made permissive to TGF-beta by GC-induced surface expression of TGF-betaRII activate in response to TGF-beta1, a multistep gene expression program featuring traits of macrophages found within an atherosclerotic lesion.

Chromium-reducing and plant growth-promoting Mesorhizobium improves chickpea growth in chromium-amended soil

Mesorhizobium strain RC3, isolated from chickpea nodules, tolerated chromium up to 500 mug/ml and reduced it by 90% at pH 7 after 120 h. It produced plant growth-promoting substances, both in the presence and absence of chromium. Strain RC3 produced 35 mug indole acetic acid/ml in Luria Bertani broth with 100 mg tryptophan/ml, which decreased with an increase in chromium concentration. Chromium application to soil at 136 mg/kg was toxic to chickpea plants but when RC3 at 136 mg/kg was also added, it increased the dry matter accumulation, number of nodules, seed yield and grain protein by 71, 86, 36 and 16%, respectively, compared to non-inoculated plants. Nitrogen in roots and shoots were increased by 46 and 40%, respectively, at 136 mg Cr/kg. The bio-inoculant decreased the uptake of chromium by 14, 34 and 29% in roots, shoots and grains, respectively.

Chromium Reduction, Plant Growth–Promoting Potentials, and Metal Solubilizatrion by Bacillus sp. Isolated from Alluvial Soil

The plant growth-promoting potentials, production of siderophore and solubilization of insoluble phosphorus (P) and zinc and lead by the chromium (vi) -reducing Bacillus species, PSB 1, PSB 7, and PSB 10, was assessed both in the presence and absence of chromium under in vitro conditions. The Bacillus strains tolerated chromium up to the concentration of 500 (PSB1), 400 (PSB7), and 550 microg ml(-1) (PSB10), respectively, on nutrient agar plates. Bacillus sp. PSB 10 reduced Cr (vi) by 87% at pH 7, which was followed by Bacillus sp. PSB 1 (83%) and PSB 7 (74%) in nutrient broth after 120 h of incubation. A concentration of 50 microg ml(-1) of Cr (vi) was completely reduced by Bacillus sp. PSB 1 and PSB 10 (after 100 h) and PSB 7 (after 120 h). The Bacillus strains PSB 1, PSB 7, and PSB 10 produced 19.3, 17.7, and 17.4 microg ml(-1) of indole acetic acid, respectively, in luria bertani broth at 100 microg ml(-1) of tryptophan, which consistently decreased with an increase in chromium concentration. The Bacillus strains were positive for siderophore, HCN, and ammonia both in the absence and presence of chromium. The Bacillus strains solubilized 375 (PSB 1), 340 (PSB 7), and 379 (PSB 10) microg ml(-1) P, respectively, in Pikovskaya broth devoid of chromium. In contrast, chromium at 150 microg ml(-1) reduced the amount of P solubilized by 17 (PSB 1), 15 (PSB 7), and 9% (PSB 10) compared to control. The tested bacterial strains solubilized a considerable amount of zinc and lead in nutrient broth both in the absence and presence of chromium. Generally, the chromium reduction and the plant growth-promoting potentials of chromium-reducing Bacillus were strongly correlated at the tested concentration of chromium. The present observations demonstrated that the chromium-reducing, metal-solubilizing, and plant growth-promoting potentials of the Bacillus strains PSB1, PSB 7, and PSB10 were not adversely affected by the chromium application and, hence, may be applied for raising the productivity of crops under metal-contaminated soils.

Lung carcinomas decrease the number of monocytes/macrophages (CD14+ cells) that produce TNF-alpha

The role that inflammation plays in cancer is puzzling. In peripheral blood, TNF-alpha-producing monocytes (CD14+ cells) were compared among patients with lung cancer, patients with tuberculosis and healthy donors; also, in pleural effusion TNF-alpha-producing CD14+ cells were compared between tuberculous patients and lung cancer patients. To analyze the level of the cellular alteration in TNF-alpha production, an experimental model was set up. TNF-alpha-producing CD14+ cells in peripheral blood from lung cancer patients were significantly lower than those from healthy donors. In pleural effusion, TNF-alpha-producing CD14+ cells were significantly lower in lung cancer patients than in tuberculous patients. Based on the results obtained from an experimental model, we suggest that this phenomenon was attributed to a reduced expression of TNF-alpha transcript. These findings provide evidence that lung carcinomas reduce TNF-alpha production by macrophages, possibly by inducing in these cells an M2 phenotype, which favor tumor progression.

Protective mechanisms of head and neck squamous cell carcinomas from immune assault

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy that is the sixth most common neoplasm in the world. Despite advances in treatments involving surgery, radiation, and chemotherapy, the 5-year survival has remained at less than 50% for the past 30 years, primarily because of local recurrences. Thus, the possibility of immunotherapeutic approaches for patients with HNSCC has gained interest. Unfortunately, patients with HNSCC have profound immune defects that are associated with increased recurrence. This review aims to provide an overview of both the defensive and immune subversive mechanisms by which patients with HNSCC can protect themselves from immune antitumor assault.

Characterization of IL-2-activated TILs and their use in intrapericardial immunotherapy in malignant pericardial effusion

Pericardial effusion (PE) and cardiac tamponade caused by malignant pericarditis are critical conditions in cancer patients, which still lack a recommended protocol for their long-term management. Percutaneous pericardiocentesis and simple drainage are commonly performed as the initial treatment. The aims of this study were to investigate the presence of cytotoxic T lymphocytes (CTLs) in malignant PE and to determine the clinical response to administering autologous tumor-infiltrating lymphocytes (TILs) into the pericardial cavity. Initially, we identified human lymphocyte antigen class-I-restricted and tumor-specific CTLs within the interleukin-2 (IL-2)-activated TILs in PEs from four patients, on the basis of interferon-gamma production and lactate dehydrogenase-release assays. Clinically we observed favorable responses to the pericardial transfer of IL-2-activated autologous TILs in four patients: one male with advanced esophageal cancer, one female with recurrent lung cancer and two females with recurrent breast cancer, respectively. Autologous TILs from PEs were expanded in vitro with IL-2, characterized for CD3, CD4 and CD8 markers, checked for contamination and then infused into the patient's pericardial space through a catheter. This was repeated biweekly. After treatment, there were no signs of recurrence of PE in either case, as determined by radiography, echocardiography and computed tomography. The only adverse effects seen were grade 1 fevers. These results suggested that intrapericardial cellular immunotherapy with autologous TILs could be a safe and effective treatment for controlling malignant pericarditis with associated cardiac tamponade, and that tumor-specific CTLs present in malignant PE might be important for tumor rejection.

Bacterial Cr(VI) reduction concurrently improves sunflower (Helianthus Annuus L.) growth

Four Cr(VI)-reducing bacterial strains (Ochrobactrum intermedium, CrT-2, CrT-3 and CrT-4) previously isolated from chromium-contaminated sites were inoculated on to seeds of sunflower (Helianthus annuus var SF-187), which were germinated and grown along with non-inoculated controls with chromate salts (300 microg CrCl3 or K2CrO4 ml(-1)). Severe reduction (20%) in seed germination was observed in Cr(VI) stress. Plant height decreased (36%) with Cr(VI) when compared with chromium-free control, while O. intermedium inoculation resulted a 20% increment in this parameter as compared to non-inoculated chromium-free control. CrT-3 inoculation resulted a 69% increment in auxin content as compared to non-inoculated control. O. intermedium caused 30% decrease in chromium uptake in sunflower plant roots under Cr(VI) stress as compared to chromium-free control plants.

Effector, memory and naïve CD8+ T cells in peripheral blood and pleural effusion from lung adenocarcinoma patients

The proportions of naïve, memory and effector CD8+ T cells in peripheral blood and pleural effusion from lung adenocarcinoma patients were studied. CD8+ T subsets were identified by using a combination of the following antibodies: anti-CD45RA, anti-CD45RO, anti-CD27 and anti-CD28, as well as antibodies to other markers. Fas-positive cells were determined in each CD8+ T subset. Also, the intracellular cytokine patterns of CD4+ and CD8+ lymphocytes from pleural effusion were analysed. In naïve, memory and effector CD8+ T subsets no significant differences were observed in peripheral blood between healthy donors and cancer patients. In contrast, a high proportion of cells with memory phenotype (CD45RA-CD45RO+CD27+CD28+) and a low proportion of cells with effector phenotype (CD45RA+CD45RO-CD27-CD28-) were found in pleural effusion with respect to peripheral blood (P<0.001). The altered proportions of CD8+ T subsets in pleural effusion were not mediated by type 2 cytokines produced by CD4+ or CD8+ lymphocytes. In the effector CD8+ T subset, from peripheral blood as well as from pleural effusion, a low percentage of perforin-expressing cells was observed compared to granzyme A-expressing cells. Additionally, a high percentage of naïve CD8+ T cells expressing Fas was found. Our data suggest that: (i) terminal-differentiation process of CD8+ T cells is blocked, and (ii) early Fas-expression in CD8+ T cells, which was reflected even in peripheral blood, may lead to apoptosis of naïve cells when they reach the effector stage. All these processes may contribute to the inadequate antitumour immune response found in lung carcinoma patients.

Immune activation status of CD8+ T cells infiltrating non-small cell lung cancer

In a variety of human cancers, the presence of tumor-infiltrating T lymphocytes (TILs) is associated with tumor regression and favorable prognosis. Local interferon (IFN)-gamma secretion from activated T cells is supposed to induce a specific immune response leading to tumor-specific cytotoxicity. Nonetheless, significance and properties of TILs still remains controversial in lung cancer patients. We determined CD8+ T cell counts in 31 patients with non-small cell lung cancer (NSCLC) by immunohistochemistry, and assessed T-cell immune activation status in a subset of patients by measuring IFN-gamma mRNA expression by quantitative PCR (TaqMan). Semi-quantitative immunohistochemical analysis revealed significantly higher CD8+ T cell counts within the tumor as when compared to the invasive margin. CD8+ T cells immune activation status, represented in the IFN-gamma/CD8 mRNA ratio, correlated with the median number of CD8+ T cells presented at the tumor-host interface. Neither tumor histology and grade, nor CD8+ T cell counts and IFN-gamma/CD8 ratio could demonstrate an influence on overall survival in these patients. Our results indicate that CD8+ T cells infiltrating the tumor cell nests may be inadequately activated and thus incapable of mounting an effective anti-tumor immune response.

Tumor-Infiltrating Lymphocyte Secretion of IL-6 Antagonizes Tumor-Derived TGF-β1 and Restores the Lymphokine-Activated Killing Activity

IL-6 is a multifunctional cytokine that regulates cell growth, differentiation, and cell survival. Many tumor cells produce TGF-beta1, which allows them to evade CTL-mediated immune responses. IL-6 antagonizes TGF-beta1 inhibition of CD3 cell activation. However, whether IL-6 restores NK activity, which also is suppressed by TGF-beta1, is not known. We used canine transmissible venereal tumor (CTVT), which produces TGF-beta1, as a model to determine whether IL-6 restores lymphokine-activated killer (LAK) activity. During the progression phase, CTVT cells stop expressing MHC molecules. During the regression phase, the number of surface MHC molecules increases dramatically on about one-third of tumor cells. Tumor cells that stop expressing MHC should be targeted by NK cells. In this study, we found that TGF-beta1 secreted by CTVT cells suppressed LAK cytotoxicity. Interestingly, tumor-infiltrating lymphocytes (TIL) isolated from regressing CTVT secrete high concentrations of IL-6 and antagonize the anti-LAK activity of tumor cell TGF-beta1. TIL also produce IL-6 during progression phase, but the concentration is too low to block the anti-LAK activity of TGF-beta1. There is probably a threshold concentration of IL-6 needed to reverse TGF-beta1-inhibited LAK activity. In addition, in the absence of TGF-beta1, IL-6 derived from TIL does not promote the activity of LAK. This new mechanism, in which TIL manufacture high concentrations of IL-6 to block tumor TGF-beta1 anti-LAK activity, has potential applications in cancer immunotherapy and tumor prognosis.