Impact of post-thoracotomy analgesia with dexmedetomidine and morphine on immunocytes: a randomized clinical trial / Impacto da analgesia pós-toracotomia com dexmedetomidina e morfina em imunócitos: estudo randomizado

Abstract Objective This study aimed to investigate the impact of post-thoracotomy analgesia with dexmedetomidine and morphine on immunocytes. Methods A total of 118 patients with post-thoracotomy Patient-Controlled Intravenous Analgesia (PCIA) in our hospital from March 2016 to July 2018 were randomly selected and divided into the Composite (COM) Group (57 patients administered with dexmedetomidine [1.0 µg.kg-1 body weight] and morphine [0.48 mg.kg-1 body weight]) and the Morphine (MOR) group (61 patients administered with morphine [0.48 mg.kg-1]). The values of lymphocyte subsets (CD3+, CD4+, and CD8+) and Natural Killer cells in the peripheral blood of these two groups were detected by FACSCalibur flow cytometry at different time points (before anesthesia induction [T0], immediately after tracheal extubation [T1], 12 hours after surgery [T2], 24 hours after surgery [T3], 48 hours after surgery [T4], 72 hours after surgery [T5], and 7 days after surgery [T6]). The doses of morphine at T3 to T5 and the adverse reactions between the two groups were also recorded and compared. Results The CD3+ level and the CD4+/CD8+ ratio at T2 to T5 and the CD4+ level and NK cells at T3 to T5 were significantly higher in the COM Group than in the MOR Group (p< 0.05). The postoperative morphine dose and the incidence of postoperative itching, nausea, and vomiting were significantly lower in the COM Group than in the MOR Group (p< 0.05). Conclusions Dexmedetomidine combined with morphine for post-thoracotomy PCIA can improve the function of immunocytes, reduce morphine consumption, and reduce the adverse reactions during analgesia induction.

Resumo Objetivo Estudar o impacto em linfócitos causado pelo uso da dexmedetomidina associada à morfina para analgesia pós-toracotomia. Método Um total de 118 pacientes utilizando Analgesia Intravenosa Controlada pelo Paciente (AICP) pós-toracotomia em nosso hospital, de março de 2016 a julho de 2018, foram selecionados aleatoriamente e divididos em dois grupos: o Grupo Combinado [COM, 57 pacientes que receberam dexmedetomidina (1,0 µg.kg-1 de peso corpóreo) associada à morfina (0,48 mg.kg-1 de peso corpóreo)] e o Grupo Morfina [MOR, 61 pacientes, que receberam somente morfina (0,48 mg.kg-)]. Os valores dos subconjuntos de linfócitos (CD3+, CD4+ e CD8+) e das células NK no sangue periférico desses dois grupos foram medidos por citometria de fluxo FACSCalibur em diferentes momentos do estudo [antes da indução anestésica (T0), imediatamente após extubação traqueal (T1), 12 horas após a cirurgia (T2), 24 horas após a cirurgia (T3), 48 horas após a cirurgia (T4), 72 horas após a cirurgia (T5) e 7 dias após a cirurgia (T6)]. As doses de morfina do momento T3 ao T5 e as reações adversas entre os dois grupos também foram registradas e comparadas. Resultados O nível de CD3+ e a razão CD4+/CD8+ de T2 a T5, e o nível de CD4+ e as células NK de T3 a T5 do Grupo COM foram significantemente maiores (p< 0,05) quando comparados ao Grupo MOR. A dose de morfina no pós-operatório e a incidência de prurido, náusea e vômito no pós-operatório foram significantemente menores no grupo MOR (p< 0,05). Conclusões Dexmedetomidina combinada com morfina para AICP no período pós-toracotomia pode melhorar a função dos linfócitos, reduzir o consumo de morfina e diminuir reações adversas durante a analgesia.

Cytotoxic activity in cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a chronic disease caused by species of the protozoan Leishmania and characterised by the presence of ulcerated skin lesions. Both parasite and host factors affect the clinical presentation of the disease. The development of skin ulcers in CL is associated with an inflammatory response mediated by cells that control parasite growth but also contribute to pathogenesis. CD8+ T cells contribute to deleterious inflammatory responses in patients with CL through cytotoxic mechanisms. In addition, natural killer cells also limit Leishmania infections by production of interferon-γ and cytotoxicity. In this review, we focus on studies of cytotoxicity in CL and its contribution to the pathogenesis of this disease.

Evaluation of immunostimulatory activity of Chyawanprash using in vitro assays.

Chyawanprash is an ayurvedic formulation used in Indian traditional medicinal system for its beneficial effect on human health. We investigated the immunostimulatory effects of Chyawanprash (CHY) using in vitro assays evaluating the secretion of cytokines such as Tumor Necrosis Factor-alpha (TNF-α), Interleukin-1beta (IL-1β) and Macrophage Inflammatory Protein-1-alpha (MIP-1-α) from murine bone marrow derived Dendritic Cells (DC) which play pivotal role in immunostimulation. The effects of CHY on phagocytosis in murine macrophages (RAW264.7) and Natural Killer (NK) cell activity were also investigated. At non-cytotoxic concentrations (20–500 µg/ml), CHY enhanced the secretion of all the three cytokines from DC. CHY also stimulated both, macrophage (RAW264.7) as well as NK cell activity, in vitro. In conclusion, the data substantiates the immunoprotective role of CHY at cellular level mediated by immunostimulation in key immune cells viz. dendritic Cells, macrophages and NK cells.

Immune enhancement activities of silk lutein extract from Bombyx mori cocoons

BACKGROUND: Declining immune function poses an important clinical challenge worldwide and supplementation with natural products that possessing immune enhancing properties is a promising approach for preventing or delaying immune function decline. Cocoons from yellow silkworms are a significant source of lutein, and this unexplored silk extract could be a viable alternative source for dietary lutein. This study assessed immunomodulatory activities of the silk lutein extract. Female BALB/c mice orally received lutein, either as silk or marigold extracts (10 or 20 mg/kg daily), or vehicle only (1% tween 80 in PBS pH 7.4) for 4 weeks. Natural killer (NK) cell activity, specific antibody production, lymphocyte subpopulations, mitogen-induced lymphocyte proliferation, and cytokine production were examined. RESULTS: Silk lutein extract increased NK cell activity, and the effect was dose-related whereas marigold lutein extract was ineffective. Silk lutein extract dose-dependently enhanced antibody production in pre-immunized mice but marigold lutein extract had no effect. Feeding with silk lutein extract increased the populations of CD3+ and CD4 + CD3 + cells. Silk lutein extract also stimulated concanavalin A- and lipopolysaccharide-induced proliferations of T and B lymphocytes, respectively. Moreover, silk lutein extract increased IL-2 and IFN-γ production while the effect of marigold lutein extract was undetectable. CONCLUSIONS: Together, silk lutein extract enhanced both innate and adaptive immune functions. This preparation may prove to be an effective supplement for strengthened immunity.

Resveratrol diminishes platelet aggregation and increases susceptibility of K562 tumor cells to natural killer cells.

Platelet aggregation around migrating cancer cells protects them against the activity of natural killer cells (NKCs). The inability of immune system to response results in the progression of malignant diseases. This study was designed to evaluate the effects of resveratrol (3, 4', 5-trihydroxystilbene) on platelet aggregation and NKCs activity. Experiments were designed to evaluate the platelet aggregation, production of thromboxane B2 (TXB2), estimation of expression of the platelet receptor GpIIb/IIIa (major biological markers for platelet aggregation) and functional activity of the NKCs against the K562 cancer cell line after incubation with various concentrations of reveratrol. Resveratrol at a concentration of 3 × 10-3Μ completely inhibited platelet aggregation (p<0.05), decreased TXB2 levels (p<0.05) and inhibited the expression of receptor GpIIb/IIIa in non-stimulated platelets (p<0.05). At the same concentration, it increased the NKCs cytotoxic activity at an average rate of 319 ± 34, 450 ± 34 and 62 ± 2.4% (p<0.05) in the NKC/targets cells ratios of 12.5:1, 25:1 and 50:1, respectively. Thus, resveratrol not only completely inhibited platelet aggregation and reduced TXB2 levels and expression of receptor GpIIb/IIIa, but also increased the cytotoxic activity of NKCs in vitro and thus increased the susceptibility of tumor cells to NKCs. Thus, resveratrol can be used as an additional supplement to modulate the immune system and to inhibit platelet aggregation in thromboembolic episodes. Further clinical investigation in vivo could lead to specific concentrations that may maximize the beneficial effect of resveratrol.

Antitumor function and mechanism of phycoerythrin from Porphyra haitanensis

The anti-tumor effect of R-Phycoerythrin (R-PE) from Porphyra haitanensis was studied using cell line HeLa as an in vitro model and Sarcoma-180 (S180) tumor-bearing mice as an in vivo model. The results showed that the combination treatment of R-PE and photodynamic therapy PDT) significantly inhibited the growth of HeLa cells up to 81.5%, with a fair dose-effect relationship, but did not inhibit endothelial cells. The annexin v-fitc/PI fluorescence staining experiments demonstrated that at doses between 0~60µg/mL, apoptosis cells and later stage apoptosis cells or necrosis cells increased significantly as the R-PE dosage increased. DNA electrophoresis showed that after R-PE+PDT treatment of HeLa cells for 24 hours, a light "smear" band between 100~400bp appeared to indicate the degradation of genomic DNA. The QRT-PCR results showed that R-PE+PDT treatment increased caspase-3 and caspase-10 gene expression and decreased the Bcl-2 gene expression level significantly as the R-PE dose increased, implying that R-PE promoted HeLa cell apoptosis. Compared with untreated S180 tumor-bearing mice, R-PE injection significantly inhibited the growth of S180 in tumor-bearing mice up to 41.3% at a dose of 300mg-kg-1. Simultaneously, the significant increase of superoxide dismutase (SOD) activity in serum (p < 0.01) and the decrease of the malondialdehyde (MDA) level in liver suggests that R-PE improved the anti-oxidant ability of the S180 tumor-bearing mice, which may related to its antitumor effect. In addition, the R-PE caused a significant increase (p < 0.05) in the spleen index and thymus index, and a significant increase (p < 0.01) in lymphocyte proliferation, NK cell kill activity and the TNF-α level in the serum of S180 tumor-bearing mice. These results strongly suggest that the antitumor effect of R-PE from Porphyra haitanensis functioned by increasing the immunity and antioxidant ability of S180 tumor-bearing mice, promoting apoptosis by increasing protease gene expression and TNF-α secretion.

IFNα2b augments immune responses of cisplatin+5-fluorouracil treated tongue squamous cell carcinoma patients - A preliminary study.

Background & objectives: Interferon alpha 2b (IFNα2b) has been reported to regulate several immune functions efficiently to enhance the cytotoxic activity of NK and T cells towards various forms of tumours. The objective of the present study was to evaluate the efficacy of IFNα2b in overcoming disease induced and/or treatment associated imunosuppression of tongue squamous cell carcinoma (TSCC) patients undergoing chemotherapy for better clinical outcome. Methods: Seven TSCC patients under cisplatin + 5-fluorouracil chemotherapy in combination with IFNα2b were assessed for various immunohaematological parameters before treatment, after chemotherapy and after IFNα2b therapy. Results: Deterioration of the haematological and immune responses was detected in immunosuppressed TSCC patients after chemotherapy. IFNα2b treatment led to a recovery in these parameters in most of the patients. Greater number of T/NK cells and enhanced secretion of type 1 cytokines were also noted. Haematological complications were reduced after completion of the therapy. Immune- and haematostimulation were also observed in patients with partial response. No positive clinical response was detected in one patient. Interpretation & conclusions: IFNα2b appears to be an effective immunostimulator having clinical impact to combat the immunosuppression in TSCC patients. Successful immunostimulation by IFNα2b may help TSCC patients in clinical improvement. The findings of this preliminary study need to be confirmed on a large number of patients with TSCC.

Effect of suicide gene therapy in combination with immunotherapy on antitumour immune response & tumour regression in a xenograft mouse model for head & neck squamous cell carcinoma.

Background & objectives: Prodrug activation strategy as well as immunotherapy have been widely used for cancer gene therapy. In the present study, using a head and neck squamous cell carcinoma (HNSCC) xenograft nude mouse model, we have investigated whether the two therapies in combination could improve tumour cell kill. We also investigated induction of immune effector cells viz., NK (DX5+) and DC (CD11c+) in vivo, post-combination gene therapy. Methods: A retroviral vector producing cell line (PLTK47.1 VPC) carrying Herpes simplex virus thymidine kinase gene (HSVtk) was used for intratumoural injection into NT8e xenograft tumours followed by the prodrug ganciclovir (GCV). IL-2 plasmid DNA was injected intramuscularly. Immune cells were analyzed by flow-cytometry. Non parametric ANOVA was performed with Kruskal Wallis test. Results: IL-2 could induce proliferation of both NK cells (DX5+) and dendritic cells (CD11c+) in vivo. Apoptosis was higher in combination therapy group as compared to HSVtk/GCV alone or IL-2 alone and was mediated through caspase-3 dependent pathway. Significant reduction in tumour volume was seen in all 3 treatment arms as compared to controls. Interpretation & conclusions: Combination of suicide gene therapy and immunotherapy leads to successful tumour regression in a HNSCC xenograft mouse model. Immunotherapy could help in a systemic long lived anti-tumour immune response which would prove powerful for the treatment of metastatic cancers, and also for minimal residual disease. The results of this study may form the basis for Phase 1 clinical trials.

Interferon therapy shifts natural killer subsets among egyptian patients with chronic hepatitis C

Natural killer cells can be divided into five subpopulations based on the relative expression of CD16 and CD56 markers. The majority of natural killer cells are CD56dim, which are considered to be the main cytotoxic effectors. A minority of the natural killer cells are CD56bright, and function as an important source of immune-regulatory cytokines. Shifts of these subsets have been reported in patients with chronic hepatitis C virus infection. We sought to investigate the shift of natural killer subsets among Egyptian patients with chronic HCV and to analyze the influence of interferon therapy on this shift. We applied a flow cytometric analysis of peripheral blood natural killer subsets for 12 interferon-untreated and 12 interferon-treated patients with chronic HCV, in comparison to 10 control subjects. Among interferon-untreated patients, there was a significant reduction of CD56-16+ (immature natural killer) cells. Among interferon-treated patients, the absolute count of natural killer cells was reduced, with expansion of the CD56bright subset and reduction of the CD56dim16+ subset. Natural killer subset counts were not significantly correlated to HCV viral load and were not significantly different among interferon responders and non-responders. In conclusion, HCV infection in Egyptian patients has been observed to be statistically and significantly associated with reduction of the CD56-16+NK subset, while a statistically significant expansion of CD56bright and reduction of CD56dim16+ subsets were observed after interferon therapy. Further studies are required to delineate the molecular basis of interferon-induced shift of natural killer subsets among patients with HCV.

Aureobasidium-Derived Soluble Branched (1,3-1,6) beta-Glucan (Sophy beta-glucan) Enhances Natural Killer Activity in Leishmania amazonensis-Infected Mice

The beta-glucans derived from yeast cell walls have been reported for having many immunomodulatory activities in vivo and in vitro. In this study, Aureobasidium-derived soluble branched (1,3-1,6) beta-glucan (Sophy beta-glucan) was checked for natural killer (NK) activity and for the production of IFN-gamma and IL-4 in Leishmania amazonensis infection. The main experiment was performed with a group of female C57BL/6 and BALB/c mice, orally supplemented with 5% of Sophy beta-glucan and infected with promastogotes of L. amazonensis (1 x 10(7)) into the footpad. Increase in the footpad thickness with time was observed in BALB/c mice in spite of the oral Sophy beta-glucan supplement, but it was less in C57BL/6 mice. The difference in overall mean footpad thickness between 'infection only' versus 'infection + glucan' groups was statistically significant (P < 0.001). High NK activity in C57BL/6 than BALB/c mice was observed in 'glucan only' group compared to the control group and also in 'infection + glucan' group compared to 'infection only' group. The difference in the NK activity among these groups was significant (P < 0.05). The IFN-gamma level increased at weeks 7 and 8 post-infection in C57BL/6 mice and was significantly high in 'infection + glucan' group compared to the 'infection only' group (P < 0.05). IL-4 levels did not increase up to detectable levels throughout the study. The results led a conclusion that Sophy beta-glucan enhances NK activity and cellular immunity in L. amazonensis-infected mice.

Nickel induces secretion of IFN-gamma by splenic natural killer cells

Although nickel hypersensitivity is known as a delayed-type hypersensitivity mediated by nickel-specific T cells, it is greatly influenced by other immune cells. Here we show that splenic natural killer cells (NK cells) directly or indirectly respond to nickel by secretion of IFN-gamma. Using enzyme-linked immunosorbent spot (ELISPOT) assays, we found that nickel-reactive cells readily secreted IFN-gamma when splenocytes were cultured in the presence of varying concentrations of nickel sulfate (NiSO4) for 24 h. However, nickel-reactive IL-2- or IL- 4-secreting cells were infrequent during the 24-h culture with NiSO4. Immune responses to nickel were innate, not adaptive, in nature since the frequency of nickel-reactive IFN-gamma-secreting cells did not increase upon previous exposure to NiSO4 and recombination activating gene (RAG)-1-deficient mice contained nickel-reactive IFN-gamma-secreting cells. The involvement of NK cells in the innate response to NiSO4 was confirmed since we could observe a significant reduction of the frequency of nickel-reactive cells in NK cell-depleted mice. Furthermore, the number of IFN-gamma secreting cells was significantly reduced in the ELISPOT assays when NKG2D was blocked by anti-NKG2D antibody. These results suggest that there is an early and rapid innate immune response to nickel, which is mediated by NK cells and the NKG2D receptor. The significance of the innate response to nickel is that it may contribute to development of the late T cell-mediated delayed type hypersensitivity against nickel.

Effect of bitter melon (Momordica charantia Linn) on level and function of natural killer cells in cervical cancer patients with radiotherapy.

Cervical cancer patients have a defective immune system. There is a decrease of total white blood cell count including lymphocytes and natural killer (NK) cells. NK cells, one type of lymphocytes, play a role to eliminate cancer cells by antibody dependent cell mediated cytotoxicity (ADCC) mechanism. Previous studies have shown that P-glycoprotein (170 kDa, transmembrane protein) may be a transporter for cytokine releasing in ADCC mechanism. This study proposed to explore the role of bitter melon intake in cervical cancer patients undergoing normal treatment (radiotherapy). Subjects were divided into three groups: 1) normal control (women 35-55 years, n = 35), 2) patient control (n = 30) and 3) patient treatment (n = 30) groups. Patient control and patient treatment groups were cervical cancer patients (stage II or III) treated with radiotherapy (without or with bitter melon ingestion). Blood samples of patient control and patient treatment groups were analyzed for NK cells percentage and P-glycoprotein level. Bitter melon is a Thai herb. Previous studies have shown that bitter melon can stimulate lymphocyte activity in vitro and in vivo (mouse). The authors hope that bitter melon could stimulate the increase of NK cells percentage and P-glycoprotein level on the membrane in blood samples from cervical cancer patients who ingest bitter melon. The results showed an increased percentage of NK cells in patient control and patient treatment groups. The increase in each group is significant (p < 0.05) when compared with the percentage of NK cells from second and third blood sampling time (after radiation with of without bitter melon intake for 45 and 90 days) with first blood sampling time (before treatment). The results also show a significant decrease of P-glycoprotein level (p < 0.05) in second and third blood sampling times when compared with first blood sampling time of the patient treatment group. There was no significant difference of P-glycoprotein (P-gp) level from first, second and third blood sampling times in patient control group. Bitter melon ingestion did not affect NK cell level but it affected the decrease of P-gp level on NK cell membrane.

Cell proliferation and natural killer cell activity by polyherbal formulation, Immu-21 in mice.

Immunomodulatory activity of an Ayurvedic polyherbal formulation, Immu-21 containing extracts of Ocimum sanctum, Withania somnifera, Emblica officinalis and Tinospora cordifolia was studied on proliferative response of splenic leukocytes to T cell mitogens, concanavalin (Con)-A and phytohemagglutinin (PHA) and B cell mitogen, lipopolysaccharide (LPS) in vitro by [3H]-thymidine uptake assay in mice. The cytotoxic activity of Immu-21 was tested by measuring the splenic leukocyte natural killer (NK) cell activity against K 562 cells. Intraperitoneal (i.p.) treatment with Immu-21 (30 mg/kg) once a day for 14 and 21 days did not cause change in body weight and spleen weight, where as splenocytes/spleen count was increased. Treatment of Immu-21 (30 mg/kg, i.p.) for 14 days and 1 mg/kg for 21 days significantly increased LPS induced leukocyte proliferation. NK cell activity was significantly increased when mice were pretreated with Immu-21 (10 and 30 mg/kg, i.p.) once a day for 7 days. The results indicate that pretreatment with Immu-21 selectively increased the proliferation of splenic leukocyte to B cell mitogen, LPS and cytotoxic activity against K 562 cells in mice.

Restoration of P-glycoprotein function is involved in the increase of natural killer activity with exogenous interleukin-15 in human immunodeficiency virus-infected individuals

A depressed level of natural killer (NK) activity is one of the various immunologic abnormalities in human immunodeficiency virus (HIV) infection. Interleukin-15 (IL-15), an immunotherapeutic candidate in HIV infection, increases NK activity and induces the excretion of CC-chemokines from divergent immune cells, but the mechanisms of NK activity enhancement by IL-15 stimulation is not clearly established in HIV infection. This study examined whether CC-chemokines, which are known to increase NK activity, are secreted adequately in HIV-infected individuals, and also investigated whether P-glycoprotein is involved in NK activity enhancement after IL-15 administration. NK activity increased with IL-15 stimulation in NK cells of HIV-infected individuals, as it does in normal NK cells. IL-15 stimulates NK cells to secrete CC-chemokines, such as, macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage chemotactic protein-1alpha (MCP-1alpha) and regulated upon activation, normal T cells expressed and secreted (RANTES) in both HIV-infected individuals and controls with no significant difference. P-glycoprotein expression and function is decreased in HIV-infected individuals and restored only in NK cells of HIV-infected individuals after IL-15 stimulation. P-glycoprotein may play a role in the mechanism of increased NK cell activity in HIV-infected individuals after IL-15 stimulation.

Interleukin-2 restores natural killer activity inhibited by sera from HIV + Hemophilic patients

Natural killer (NK) activity is impaired in patients with positive serology for the human immunodeficiency virus (HIV). We previously found an inhibitory effect of sera from hemophilic (He) HIV+ patients on normal NK activity. In the present study, we have further characterized this effect by studying its reversibility, temperature and time incubation dependence. Since interleukin 2 (IL-2) is able to enhance NK levels, we analized the capacity of this lymphokine to reverse the effect of He HIV+ sera. We found that when IL-2 activation of NK activity occurred simultaneously or after HIV+ serum-treatment, a significant restoration of NK function was observed. In contrast, preincubation with IL-2 did not affect the inhibitory effect exerted by HIV+ sera.

Immunopotentiating activity of septilin.

Oral administration of septilin (100mg/animal/dose; five doses) was found to enhance natural killer cell mediated cytotoxicity and antibody-dependent cellular cytotoxicity in normal mice as well as tumour-bearing mice. Septilin treatment also activated the peritoneal macrophages which produced cytotoxicity to L929 cells. Septilin increased proliferation of bone-marrow cells and there was an increase in the number of alpha-naphthyl acetate esterase staining cells in the bone-marrow. In addition to the activation of cellular immunity, septilin was found to increase the number of antibody producing cells in the spleen and activation of antibody-dependent complement-mediated cell lysis. These studies justifies the use of this herbal preparation in improving immunocompetence in disease states.

Radioprotective effects of Rasayanas.

Oral administration of Rasayanas (indigenous preparations made up of herbal drugs) significantly increased total WBC count, bone marrow cellularity, natural killer cell and antibody dependent cellular cytotoxicity in gamma radiation (4 Gy) exposed mice. Also, Rasayanas reduced radiation induced lipid peroxidation in liver. The possible mechanisms of action of Rasayanas could be increased stem cell proliferation and its effect on free radical induced injury produced by radiation.

Natural killer cells and interleukin-12 in patients with advanced cervical cancer under neoadvanced chemotherapy

Patients with advanced cervical cancer have deficient natural killer (NK) cell activity, usually as a consequence of tumor invasion, which results in tumor NK cell sequestration. The reason for the occurrence of such alterations in patients under chemotherapy is unknown. We evaluated the activity and number of NK cells and T cell subpopulations in ten patients before and three weeks after neoadjuvant chemotherapy (CT). The schedule used was cis-platinum (100 Mg/M2 per cycle) and bleomycin (15 mg/cycle), repeated every 28 days. Although there were similar levels of NK cells before and after CT in both groups, we observed greater cytotoxicity of peripheral blood lymphocytes and increased levels of CD4+ and CD8+ T cells (P<0.01) in five patients who presented a good clinical response when compared to the group with a poor response. IL- 12, known to increase NK cell activity when added to peripheral blood lymphocyte cultures, markedly increased lytic activity before and after CT only in the group with a good clinical response. These results suggest that NK cells from the poorly responding patient group express less lytic activity per NK cell and are insensitive to IL- 12 stimulation, probably as a result of reduced IL-12 receptor expression or a defective intracellular transduction mechanism. The present findings may be useful as a prognostic factor in clinical practice and also provide support for human clinical trials of IL- 12 and neoadjuvant CT for the treatment of malignant cervical tumors.

In vitro effect of methyl mercury on natural killer cells activity

The effect of in vitro treatment with methyl mercury on mouse natural killer [NK] cell activity and conjugate formation was studied. Lymphocytes preincubated with 10-6 M methyl mercury at room temperature for one hour showed significant suppression in NK activity and conjugate formation [38% and 40%, respectively] at effector: target [E: T] ratio of 25: 1 compared with control lymphocytes. Complete inhibition of NK activity and conjugate formation [78% and 77%, respectively] at 25: 1 ratio occurred when lymphocytes were preincubated with 10-3 M methyl mercury. The effect of methyl mercury may be attributed to the decrease in the percentage of conjugate formation between splenic NK cells and target tumor cells. It can be concluded that methyl mercury has a potential inhibitory effect on NK activity and this may lead to malignancy

Efeito inibidor do crescimento tumoral pela metionina-encefalina / Inhibitory effect of tumor growth by methionine-enkephalin

A metionina-encefalina (Met-Enk) é um pentapeptídeo opióide derivado do prónormônio proencefalina A, presente em células neuroendócrinas e hematopoéticas. Estudos experimentais evidenciam seu papel na induçäo, ativaçäo e controle de eventos imunomoduladores, inclusive com potente efeito inibidor do crescimento tumoral. O presente estudo demonstra que o efeito inibidor da Met-Enk no crescimento de um fibro-histocitoma, em camundongos BALB/cJ, é influenciado pelo protocolo utilizado, via de administraçäo e dose do pentapeptídeo opióide utilizada no tratamento. A administraçäo de Met-Enk por via intracerebral retardou de forma eficiente o processo de tumorigênese, aumentando a sobrevida dos animais e reduzindo de forma significativa a área tumoral final. Dose baixa (0,25mg/Kg) de Met-Enk administrada por via intracerebral foi ainda mais potente no controle da tumorigênese