Зміст журналу за 2009 р.

Item does not contain fulltextT-helper 1 and 17 (Th1/Th17) responses are important in inflammatory bowel disease (IBD), and research indicates that Toll-like receptor 6 (TLR6) stimulation leads to Th17 cell development within the lung. The gastrointestinal tract, like the lung, is a mucosal surface that is exposed to bacterially derived TLR6 ligands. Thus, we looked at the effects of TLR6 stimulation on the expression of Th17-, Th1-, and regulatory T-cell-associated transcription factors; RORgammat, T-bet, and Foxp3, respectively; in CD4+ T cells within gut-associated lymphoid tissue (GALT) in vitro and in vivo. Cells from GALT and spleen were stimulated with anti-CD3 and TLR ligands for TLR1/2 and TLR2/6 (Pam3CSK4 and FSL-1, respectively). FSL-1 was more effective than Pam3CSK4 at inducing Th1 and Th17 responses in the GALT while Pam3CSK4 rivaled FSL-1 in the spleen. TLR6 was further explored in vivo using experimental colitis. Tlr6-/- mice were resistant to colitis, and oral FSL-1 led to more severe colitis in wild-type mice. Similar pro-inflammatory reactions were seen in human peripheral blood mononuclear cells, and TLR6 expression was directly correlated with RORC mRNA levels in inflamed intestines of IBD patients. These results demonstrate that TLR6 supports Th1- and Th17-skewed responses in the GALT and might be an important target for the development of new medical interventions in IBD

In situ tumor destruction: towards in vivo modulation of immune responses by dendritic cells.

Contains fulltext : 27426.pdf (publisher's version ) (Open Access)Dendritic cells (DC's) are professional antigen presenting cells that play a critical role in initiation of immune responses. In recent years, it has become evident that tumor antigens presented by ex vivo generated DC can evoke tumor-specific responses in cancer patients. Although promising results have been obtained with tumor antigen loaded DC vaccination, many questions regarding the most effective tumor antigens and DC migration remain unanswered. Moreover, ex vivo generation of DC's is time consuming and costly. In vivo loading and maturation of DC's would therefore greatly improve the applicability of DC vaccination. For in vivo loading of DC's we pioneered on a novel mouse model that makes use of in situ tumor ablation (cryo and radiofrequency ablation) to create an antigen source for uptake by phagocytes. In this model we could show that after ablation, antigens were preferentially taken up by dendritic cells in the draining lymph node. This, however, induced only a minor anti-tumor immunity that was mainly cell-mediated and tumor-specific. We and others showed that the maturation and activation status of DC's is crucial for the outcome of vaccination. Thus, to enhance immune responses after in vivo loading we combined the ablative treatments with peri-tumoral injection of CpG ODN containing unmethylated CG motifs. We were able to trace back antigen positive DC's in the lymph nodes that were increasingly matured after CpG, compared to antigen negative DC's. This was accompanied by an increase in cross presentation of antigens and subsequent induction of specific CD8+ T cells. Accordingly, this strategy decreased the basal level of primary site recurrences. Furthermore, when a re-challenge with B16-OVA cells was given forty days after ablation we could obtain 100% protection from outgrowth of this re-challenge. The results presented in this thesis suggest that immunomodulation can be a powerful additive treatment modality to combine with in situ tumor ablation.RU Radboud Universiteit Nijmegen, 26 april 2006Promotores : Adema, G.J., Figdor, C.G. Co-promotores : Ruers, T.J.M., Sutmuller, R.P.M.180 p

Sweet escape: Sialic acids in tumor immune evasion

Sialic acids represent a family of sugar molecules derived from neuraminic acid that frequently terminate glycan chains and contribute to many biological processes. Already five decades ago, aberrantly high expression of sialic acids has been proposed to protect cancer cells from recognition and eradication by the immune system. Today, increased understanding at the molecular level demonstrates the broad immunomodulatory capacity of tumor-derived sialic acids that is, at least in part, mediated through interactions with immunoinhibitory Siglec receptors. Here we will review current studies from a sialic acid sugar perspective showing that tumor-derived sialic acids disable major killing mechanisms of effector immune cells, trigger production of immune suppressive cytokines and dampen activation of antigen-presenting cells and subsequent induction of anti-tumor immune responses. Furthermore, strategies to modulate sialic acid expression in cancer cells to improve cancer immunotherapy will be discussed

Sialic Acids Sweeten a Tumor's Life

Item does not contain fulltextOver four decades ago, specific tumor characteristics were ascribed to the increased expression of sialic acid sugars on the surface of cancer cells, and this led to the definition of sialic acids as potential therapeutic targets. Recent advances in glycobiology and cancer research have defined the key processes underlying aberrant expression of sialic acids in cancer, and its consequences, more precisely. These consequences include effects on tumor growth, escape from apoptosis, metastasis formation, and resistance to therapy. Collectively, these novel insights provide further rationale for the design and development of therapeutic approaches that interfere with excessively high expression of sialic acids in cancer cells. Strategies to target aberrant sialylation in cancer, however, have evolved comparatively slowly. Here, we review recent findings that emphasize the detrimental effects of hypersialylation on multiple aspects of tumor growth and behavior. We also discuss novel therapeutic strategies. Cancer Res; 74(12); 3199-204. (c)2014 AACR

Dendritic cells: tools and targets for antitumor vaccination.

Item does not contain fulltextDendritic cells are the most potent antigen-presenting cells of the immune system and represent a promising tool in therapeutic vaccination against cancer. Immunotherapy applying ex vivo-generated and tumor antigen-loaded dentritic cells has been successfully introduced in clinical vaccination protocols and has proven to be feasible and effective in some patients. A better understanding of how dentritic cells succeed to induce and modulate immunity is necessary to optimally exploit dentritic cells in anticancer vaccines. The authors will review novel insights in antigen loading, activation and migration of dentritic cells and their impact on the application of ex vivo-generated dentritic cell vaccines. In addition, novel means to exploit dentritic cells in cancer vaccines by loading and activation of dentritic cells directly in situ and possible obstacles that should be overcome to induce long-lasting immunity in therapeutic settings will be discussed

Synergy between in situ tumor destruction and TLR stimulation: An evolving approach in immunotherapy

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Thermal and mechanical high-intensity focused ultrasound: perspectives on tumor ablation, immune effects and combination strategies

Tumor ablation technologies, such as radiofrequency-, cryo- or high-intensity focused ultrasound (HIFU) ablation will destroy tumor tissue in a minimally invasive manner. Ablation generates large volumes of tumor debris in situ, releasing multiple bio-molecules like tumor antigens and damage-associated molecular patterns. To initiate an adaptive antitumor immune response, antigen-presenting cells need to take up tumor antigens and, following activation, present them to immune effector cells. The impact of the type of tumor ablation on the precise nature, availability and suitability of the tumor debris for immune response induction, however, is poorly understood. In this review, we focus on immune effects after HIFU-mediated ablation and compare these to findings using other ablation technologies. HIFU can be used both for thermal and mechanical destruction of tissue, inducing coagulative necrosis or subcellular fragmentation, respectively. Preclinical and clinical results of HIFU tumor ablation show increased infiltration and activation of CD4+ and CD8+ T cells. As previously observed for other types of tumor ablation technologies, however, this ablation-induced enhanced infiltration alone appears insufficient to generate consistent protective antitumor immunity. Therapies combining ablation with immune stimulation are therefore expected to be key to boost HIFU-induced immune effects and to achieve systemic, long-lasting, antitumor immunity

Le rôle des parents dans le développement des jeunes joueurs de football et de tennis brésiliens

The best known method of high-intensity focused ultrasound is thermal ablation, but interest in non-thermal, mechanical destruction is increasing. The advantages of mechanical ablation are that thermal protein denaturation remains limited and less damage is created to the surrounding tissue by thermal diffusion. The two main techniques for mechanical fragmentation of tissue are histotripsy and boiling histotripsy. These techniques can be used for complete liquefaction of tumor tissue into submicron fragments, after which the fragmented tissue can be easily removed by natural (immunologic) responses. Interestingly it seems that there is a correlation between the degree of destruction and tissue specific characteristics based on the treatment settings used. In this review article, the technical aspects of these two techniques are described, and an overview of the in vivo pathologic and immunologic responses is provided

Examination of coaches' self-efficacy : preliminary analysis of the coaching efficacy scale

In around half of the patients with neuroblastoma (NBL), the primary tumor is located in one of the adrenal glands. We have previously reported on a transplantable TH-MYCN model of subcutaneous (SC) growing NBL in C57Bl/6 mice for immunological studies. In this report, we describe an orthotopic TH-MYCN transplantable model where the tumor cells were injected intra-adrenally (IA) by microsurgery. Strikingly, 9464D cells grew out much faster in IA tumors compared to the subcutis. Tumors were infiltrated by equal numbers of lymphocytes and myeloid cells. Within the myeloid cell population, however, tumor-infiltrating macrophages were more abundant in IA tumors compared to SC tumors and expressed lower levels of MHC class II, indicative of a more immunosuppressive phenotype. Using 9464D cells stably expressing firefly luciferase, enhanced IA tumor growth could be confirmed using bioluminescence. Collectively, these data show that the orthotopic IA localization of TH-MYCN cells impacts the NBL tumor microenvironment, resulting in a more stringent NBL model to study novel immunotherapeutic approaches for NBL