Changes of liver-resident NK cells during liver regeneration in rats

To determine the role of NK cells in regulation of tissue growth, the phenotype and function of liver-resident NK cells were studied after 70% partial hepatectomy in rats. The process of liver regeneration was generally completed by clay 14. In contrast, the number of liver resident NK cells (NKR-P1(bright)) was restored as early as day 3 after partial hepatectomy. However, spontaneous functions of liver resident NK cells, including killing of YAC-1 and P815 targets, Ab-dependent cellular cytotoxicity, and redirected killing via NKR-P1, were continuously suppressed throughout the entire period of liver regeneration (from 3 h to 14 days). Augmentation of NK cytotoxicity against P815 targets and induction of NK cell adherence to plastic following 24 h of IL-2 stimulation showed a similar pattern of suppression. However, IL-2-induced augmentation of YAC-1 killing, proliferation and generation of adherent NK cells, and LAK activity in 5- to 7-day cultures were found to be suppressed only during the first 24 h and increased between days 2 and 7 after hepatectomy. Sorted NK cells (≥95% NKR-P1(bright)) from liver-resident mononuclear leukocytes 24 h after partial hepatectomy showed the same pattern of suppression as unsorted mononuclear leukocytes. In contrast to liver- resident NK cells, no significant changes were detected in peripheral blood or spleen NK cells of rats following partial hepatectomy. Of particular interest, in normal liver, hepatocytes were resistant to NK lysis, while resident NK cells were cytotoxic for various NK-sensitive targets. In contrast, during the early period of liver regeneration, when hepatocytes were sensitive to lysis by liver resident NK cells of normal rats, NK cells obtained from regenerating liver tissues were unable to mediate cytotoxicity. At the final phase of liver regeneration (days 7-14 after hepatectomy), both resistance of hepatocytes to killing by NK cells and cytotoxicity of liver- resident lymphocytes against hepatocytes from regenerating liver were simultaneously restored. In vivo depletion of NK cells by injection of rats with anti-NKR-P1 mAb resulted in a significant augmentation of liver regeneration subsequent to partial hepatectomy. Our data suggest that liver- resident NK cells may he involved in regulation of the extent of liver regeneration

Monounsaturated fats and immune function

Animal studies suggest that olive oil is capable of modulating functions of cells of the immune system in a manner similar to, albeit weaker than, fish oils. There is some evidence that the effects of olive oil on immune function in animal studies are due to oleic acid rather than to trace elements or antioxidants. Importantly, several studies have demonstrated effects of oleic acid-containing diets on in vivo immune responses. In contrast, consumption of a monounsaturated fatty acid (MUFA)-rich diet by humans does not appear to bring about a general suppression of immune cell functions. The effects of this diet in humans are limited to decreasing aspects of adhesion of peripheral blood mononuclear cells, although there are trends towards decreases in natural killer cell activity and proliferation. The lack of a clear effect of MUFA in humans may be attributable to the higher level of monounsaturated fat used in the animal studies, although it is ultimately of importance to examine the effects of intakes which are in no way extreme. The effects of MUFA on adhesion molecules are potentially important, since these molecules appear to have a role in the pathology of a number of diseases involving the immune system. This area clearly deserves further exploration

Plasmodium falciparum-Infected Erythrocytes Induce Granzyme B by NK Cells through Expression of Host-Hsp70

In the early immune response to Plasmodium falciparum-infected erythrocytes (iRBC), Natural Killer (NK) cells are activated, which suggests an important role in innate anti-parasitic immunity. However, it is not well understood whether NK cells directly recognize iRBC or whether stimulation of NK cells depends mainly on activating signals from accessory cells through cell-to-cell contact or soluble factors. In the present study, we investigated the influence of membrane-bound host Heat shock protein (Hsp) 70 in triggering cytotoxicity of NK cells from malaria-naïve donors or the cell line NK92 against iRBC. Hsp70 and HLA-E membrane expression on iRBC and potential activatory NK cell receptors (NKG2C, CD94) were assessed by flow cytometry and immunoblot. Upon contact with iRBC, Granzyme B (GzmB) production and release was initiated by unstimulated and Hsp70-peptide (TKD) pre-stimulated NK cells, as determined by Western blot, RT-PCR and ELISPOT analysis. Eryptosis of iRBC was determined by Annexin V-staining. Our results suggest that presence of Hsp70 and absence of HLA-E on the membrane of iRBC prompt the infected host cells to become targets for NK cell-mediated cytotoxicity, as evidenced by impaired parasite development. Contact of iRBC with NK cells induced release of GzmB. We propose that following GzmB uptake, iRBC undergo eryptosis via a perforin-independent, GzmB-mediated mechanism. Since NK activity toward iRBC could be specifically enhanced by TKD peptide and abrogated to baseline levels by blocking Hsp70 exposure, we propose TKD as an innovative immunostimulatory agent to be tested as an adjunct to anti-parasitic treatments in vivo

Enhanced antitumor efficacy of cisplatin in combination with HemoHIM in tumor-bearing mice

<p>Abstract</p> <p>Background</p> <p>Although cisplatin is one of the most effective chemotherapeutic agents, cisplatin alone does not achieve a satisfactory therapeutic outcome. Also cisplatin accumulation shows toxicity to normal tissues. In this study, we examined the possibility of HemoHIM both to enhance anticancer effect with cisplatin and to reduce the side effects of cisplatin in melanoma-bearing mice.</p> <p>Methods</p> <p>HemoHIM was prepared by adding the ethanol-insoluble fraction to the total water extract of a mixture of 3 edible herbs, Angelica Radix, Cnidium Rhizoma and Paeonia Radix. Anticancer effects of HemoHIM with cisplatin were evaluated in melanoma-bearing mice. We used a Cr⁵¹-release assay to measure the activity of NK/Tc cell and ELISA to evaluate the production of cytokines.</p> <p>Results</p> <p>In melanoma-bearing mice, cisplatin (4 mg/kg B.W.) reduced the size and weight of the solid tumors, and HemoHIM supplementation with cisplatin enhanced the decrease of both the tumor size (p < 0.1) and weight (p < 0.1). HemoHIM itself did not inhibit melanoma cell growth <it>in vitro</it>, and did not disturb the effects of cisplatin <it>in vitro</it>. However HemoHIM administration enhanced both NK cell and Tc cell activity in mice. Interestingly, HemoHIM increased the proportion of NK cells in the spleen. In melanoma-bearing mice treated with cisplatin, HemoHIM administration also increased the activity of NK cells and Tc cells and the IL-2 and IFN-γ secretion from splenocytes, which seemed to contribute to the enhanced efficacy of cisplatin by HemoHIM. Also, HemoHIM reduced nephrotoxicity as seen by tubular cell of kidney destruction.</p> <p>Conclusion</p> <p>HemoHIM may be a beneficial supplement during cisplatin chemotherapy for enhancing the anti-tumor efficacy and reducing the toxicity of cisplatin.</p

Treatment with interleukin-2 in malignant pleural mesothelioma: immunological and angiogenetic assessment and prognostic impact

BACKGROUND: Administration of interleukin-2 (IL-2) has shown some effects on malignant pleural mesothelioma (MPM) tumour regression. The purpose of this study was to investigate the ability of IL-2 to modify immunological effector cells and angiogenesis in MPM patients and their prognostic value. METHODS: Tumour-infiltrating lymphocytes (CD4, CD8, Foxp3), mast cells (MCs) (tryptase and chymase), microvessel count (MVC) and VEGF were determined by immunohistochemistry in two series of MPM patients: 60 patients treated with intra-pleural preoperative IL-2 and 33 patients untreated. RESULTS: Tryptase MCs, and CD8 and Foxp3 lymphocytes were significantly increased in the IL-2-treated group, whereas MVC was significantly lower in the same group. Moreover, in the IL-2-treated group, greater tryptase + MCs and greater Foxp3 lymphocytes were associated with improved and poorer clinical outcomes, respectively. Notably, when these two immunological parameters were combined, they predicted outcomes more effectively. CONCLUSIONS: This study showed that IL-2 treatment leads to a significant increase of immunological parameters, concomitantly with a reduction in vasculature, providing new insight into the cancer mechanisms mediated by IL-2. Moreover, these results suggest that tryptase-positive MCs and Foxp3 + lymphocytes predict clinical outcomes in IL-2-treated patients, highlighting the critical role of the inflammatory response in mesothelioma cancer progression. British Journal of Cancer (2009) 101, 1869-1875. doi:10.1038/sj.bjc.6605438 www.bjcancer.com (C) 2009 Cancer Research U

Natural killer cells are crucial for the efficacy of Icon (factor VII/human IgG1 Fc) immunotherapy in human tongue cancer

<p>Abstract</p> <p>Background</p> <p>Icon is a novel, dual neovascular- and cancer cell-targeting immunotherapeutic agent and has shown efficacy in the treatment of cancer, wet form macular degeneration and endometriosis. However, its underlying mechanism remains to be investigated. The objective of this study is to elucidate the mechanism of Icon immunotherapy in cancer using a squamous carcinoma human tongue cancer line TCA8113 <it>in vitro </it>and <it>in vivo </it>in severe combined immunodeficiency (SCID) mice.</p> <p>Results</p> <p>We showed that Icon, as a chimeric factor VII and human IgG1 Fc immunoconjugate, could separately induce murine natural killer (NK) cells and activate complement to kill TCA8113 cancer cells <it>in vitro </it>via antibody dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). However, Icon-NK ADCC had a significantly stronger effect than that of Icon-CDC. Moreover, Icon could completely eradicate established human tongue tumour xenografts <it>in vivo </it>in the CB-17 strain of SCID mice that have functional NK cells at a normal level, whereas it was less effective in SCID/Beige mice that do not have functional NK cells.</p> <p>Conclusions</p> <p>We conclude that NK cells are crucial for the efficacy of Icon immunotherapy in the treatment of cancer. The results also suggest that impaired NK level/activity could contribute to the resistance to therapeutic antibodies that are currently under investigation in preclinical and clinical studies.</p

Immunoregulatory dysfunctions in type I diabetes: Natural and antibody-dependent cellular cytotoxic activities

Peripheral blood lymphocytes from 13 patients with established insulin-dependent diabetes mellitus (IDDM) and 2 prediabetic patients were examined for natural killer (NK) and antibody-dependent cellular cytotoxic activities (ADCC), lectin-dependent cellular cytotoxicity (LDCC), interferon- and interleukin-2-induced cytotoxicity, and concanavalin A-induced suppressor-cell activities in comparison with age-matched normal controls. IDDM patients demonstrated normal levels of NK and ADCC activities against K562 and antibody-coated SB target cells, respectively, compared to controls. IDDM patients showed normal levels of LDCC activity. Notable deviations from control values were, however, observed with diabetic lymphocytes in the following systems. Interferon-and interleukin-2-induced NK activities were significantly higher with IDDM lymphocytes than with control cells. IDDM lymphocytes precultured with concanavalin A demonstrated lower NK and ADCC activities than control cells and manifested decreased suppressor effects on the NK activity of normal allogeneic lymphocytes. Lymphocytes from one of two prediabetic patients showed increased NK, ADCC, and LDCC activities in comparison to controls. The increased interferon- and interleukin-2-induced enhancement of NK activity and reduced suppressor activity of lymphocytes from IDDM patients may be involved in the pathogenesis of the disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44848/1/10875_2004_Article_BF00915375.pd