Enhancement of anti-tumour immunity by transduction with a <i>Mycobacterium tuberculosis</i> gene

As a strategy to enhance immune response against tumours by a "danger signal", the Mycobacterium tuberculosis Ag38 gene encoding an highly immunogenic protein has been transduced in tumour cells. The gene was stably expressed on tumour cell surface by using a retroviral vector modified to express the leader and transmembrane sequences of the Nerve Growth Factor Receptor. Transduced cells have been used as a cellular vaccine in syngeneic mice and their ability to elicit an anti-tumour response has been evaluated against both a transplanted tumour model and against a spontaneous tumour model. In the transplanted melanoma model, vaccination with transduced cells induced a significant protection against subcutaneous or intravenous challenge with non transduced cells. In Ag38-transduced vaccinated mice a preferential Thl response was observed. Moreover, after challenge, a high titre of antibodies directed against tumour cells was detected in protected mice. Most of these antibodies were directed against endogenously expressed viral antigens, while no reactivity against melanocyte lineage specific antigens was observed. In the HER2/Neu transgenic mice model, which spontaneously develop stochastic mammary tumours after a long latency period, the onset of tumour development was significantly delayed in mice vaccinated with Ag38-transduced cells. The delay in tumour development was increased when mice were vaccinated with the Ag38 transduced vaccine plus ·a systemic administration of IL-12 at . ~ low dose. Consistent with melanoma model, a preferential Thl profile was observed in mice in response to vaccination with Ag38-transduced cells and a CD3+CD8+ population able to respond to the tumour with IFN-y production was derived from these mice. No humoral response was induced in protected mice, while an activated CD4+ T cell population producing IL-4 was obtained from long-survived mice

Critical Role of TLR9 in Acute Graft-versus-Host Disease

Abstract Graft-vs-host disease (GVHD) is a major complication after allogeneic bone marrow transplantation. Different studies have demonstrated that intestinal bacterial breakdown products and loss of gastrointestinal tract integrity, both induced by conditioning regiments, are critical in the pathogenesis of acute GVHD. Using C57BL/6 knockout mice, we evaluated the role of TLR4 and TLR9, which recognize bacterial LPS and DNA, respectively, in the GVHD associated with allogeneic bone marrow transplantation. When myeloablative-irradiated TLR9 knockout (TLR9−/−) mice were used as graft recipients, survival and clinical score of acute GVHD were improved as compared with the wild-type recipient mice (18/30 vs 1/31 mice still alive at day 70 in a total of four experiments); while no differences were observed using recipient TLR4 knockout (TLR4−/−) mice. The reduced mortality and morbidity in TLR9−/− mice related with reduced stimulatory activity of TLR9−/− spleen APCs after conditioning and reduced proliferation of allogeneic donor T cells. Experiments using TLR9+/+ into TLR9−/− and TLR9−/− into TLR9+/+ chimeric mice as recipients indicated a critical role for nonhematopoietic TLR9+/+ cells interacting with bacterial breakdown products released in myeloablated mice. Altogether these data reveal a novel important role of TLR9 in GVHD, a finding that might provide tools to reduce this complication of allogeneic transplantation

Taxanes enhance trastuzumab-mediated ADCC on tumor cells through NKG2D-mediated NK cell recognition

Recent clinical data indicate a synergistic therapeutic effect between trastuzumab and taxanes in neoadjuvantly treated HER2-positive breast cancer (BC) patients. In HER2+ BC experimental models and patients, we investigated whether this synergy depends on the ability of drug-induced stress to improve NK cell effectiveness and thus trastuzumab-mediated ADCC. HER2+ BC cell lines BT474 and MDAMB361 treated with docetaxel showed up-modulation of NK activator ligands both in vitro and in vivo, accompanied by a 15-40% increase in in vitro trastuzumab-mediated ADCC; antibodies blocking the NKG2D receptor significantly reduced this enhancement. NKG2D receptor expression was increased by docetaxel treatment in circulating and splenic NK cells from mice xenografted with tumor cells, an increase related to expansion of the CD11b+Ly6G+ cell population. Accordingly, NK cells derived from HER2+ BC patients after treatment with taxane-containing therapy expressed higher levels of NKG2D receptor than before treatment. Moreover, plasma obtained from these patients recapitulated the modulation of NKG2D on healthy donors' NK cells, improving their trastuzumab-mediated activity in vitro. This enhancement occurred mainly using plasma from patients with low NKG2D basal expression. Our results indicate that taxanes increase tumor susceptibility to ADCC by acting on tumor and NK cells, and suggest that taxanes concomitantly administered with trastuzumab could maximize the antibody effect, especially in patients with low basal immune effector cytotoxic activit

Early immune modulation by single-agent trastuzumab as a marker of trastuzumab benefit

BACKGROUND: Optimising the selection of HER2-targeted regimens by identifying subsets of HER2-positive breast cancer (BC) patients who need more or less therapy remains challenging. We analysed BC samples before and after treatment with 1 cycle of trastuzumab according to the response to trastuzumab. METHODS: Gene expression profiles of pre- and post-treatment tumour samples from 17 HER2-positive BC patients were analysed on the Illumina platform. Tumour-associated immune pathways and blood counts were analysed with regard to the response to trastuzumab. HER2-positive murine models with differential responses to trastuzumab were used to reproduce and better characterise these data. RESULTS: Patients who responded to single-agent trastuzumab had basal tumour biopsies that were enriched in immune pathways, particularly the MHC-II metagene. One cycle of trastuzumab modulated the expression levels of MHC-II genes, which increased in patients who had a complete response on treatment with trastuzumab and chemotherapy. Trastuzumab increased the MHC-II-positive cell population, primarily macrophages, only in the tumour microenvironment of responsive mice. In patients who benefited from complete trastuzumab therapy and in mice that harboured responsive tumours circulating neutrophil levels declined, but this cell subset rose in nonresponsive tumours. CONCLUSIONS: Short treatment with trastuzumab induces local and systemic immunomodulation that is associated with clinical outcomes

Antitumor Activity of the TLR-5 Ligand Flagellin in Mouse Models of Cancer

Abstract Flagellin, the structural protein subunit of the bacterial flagellum, is specifically recognized by TLR-5 and has potent immunomodulatory effects. The antitumor effects of purified Salmonella typhimurium flagellin were evaluated in mice transplanted s.c. with a weakly immunogenic murine tumor or with its variant stably transfected to express the highly antigenic human HER-2 oncoprotein. Peritumoral administration of flagellin 8–10 days after tumor implantation did not affect the growth rate of the weakly immunogenic tumor but significantly inhibited growth of the antigenic variant tumor. In contrast, flagellin administered at the time of implantation of the antigenic tumor led to accelerated tumor growth. These contrasting effects of flagellin on tumor growth correlated with the type of immune response induced; i.e., late flagellin administration was associated with an increased IFN-γ:IL-4 ratio and the decreased frequency of CD4+CD25+ T regulatory cells, whereas flagellin treatment at the time of tumor implantation decreased the IFN-γ:IL-4 ratio and increased CD4+CD25+ T cell frequency. When the early flagellin treatment was combined with administration of CpG-containing oligodeoxynucleotides, tumor growth was completely suppressed, indicating synergy between flagellin and CpG-containing oligodeoxynucleotides. Together, these data provide evidence that flagellin can have contrasting effects on tumor growth

Polyphenols&ndash;Gut&ndash;Heart: An Impactful Relationship to Improve Cardiovascular Diseases

A healthy gut provides the perfect habitat for trillions of bacteria, called the intestinal microbiota, which is greatly responsive to the long-term diet; it exists in a symbiotic relationship with the host and provides circulating metabolites, hormones, and cytokines necessary for human metabolism. The gut&ndash;heart axis is a novel emerging concept based on the accumulating evidence that a perturbed gut microbiota, called dysbiosis, plays a role as a risk factor in the pathogenesis of cardiovascular disease. Consequently, recovery of the gut microbiota composition and function could represent a potential new avenue for improving patient outcomes. Despite their low absorption, preclinical evidence indicates that polyphenols and their metabolites are transformed by intestinal bacteria and halt detrimental microbes&rsquo; colonization in the host. Moreover, their metabolites are potentially effective in human health due to antioxidant, anti-inflammatory, and anti-cancer effects. The aim of this review is to provide an overview of the causal role of gut dysbiosis in the pathogenesis of atherosclerosis, hypertension, and heart failure; to discuss the beneficial effects of polyphenols on the intestinal microbiota, and to hypothesize polyphenols or their derivatives as an opportunity to prevent and treat cardiovascular diseases by shaping gut eubiosis

Use of a self-etching primer in combination with a resin-modified glass ionomer: effect of water and saliva contamination on shear bond strength

The purpose of this study was to evaluate the effects of 3 different enamel conditioners (10% polyacrylic acid, 37% phosphoric acid, and self-etching primer) on the shear bond strength and site of bond failure of a resin-modified glass ionomer (Fuji Ortho LC, GC Europe, Leuven, Belgium) bonded onto dry, water-moistened, and saliva-moistened enamel. One hundred eighty bovine permanent mandibular incisors were randomly divided into 12 groups; each group consisted of 15 specimens. Three different enamel surface conditions were studied: dry, soaked with water, soaked with saliva. One hundred eighty stainless steel brackets were bonded with the resin-modified glass ionomer. After bonding, all samples were stored in distilled water for 24 hours and then tested in a shear mode on a testing machine. After self-etching primer application, Fuji Ortho LC produced the highest shear bond strengths under all the different enamel surface conditions; these values were significantly higher than those achieved in the remaining groups, except when Fuji Ortho LC was used in combination with 37% phosphoric acid on dry enamel. Fuji Ortho LC bonded without enamel conditioning produced the lowest shear bond strengths. The bond strength of the groups conditioned with 10% polyacrylic acid was significantly lower than that of the groups etched with 37% phosphoric acid, except when both conditioners were used on enamel soaked with water