Search results for "immune system"

Increased regulatory T-cell frequencies in patients with advanced melanoma correlate with a generally impaired T-cell responsiveness and are restored…

2009

Naturally occurring CD4(+) CD25(+) regulatory T-cell (Treg) activity is assumed to facilitate tumor development and progression. To elucidate the possible role of Tregs in the course of melanoma progression, we analysed the frequency of Tregs in the peripheral blood of patients at melanoma stages I-IV and in patients at melanoma stage IV that underwent dendritic cell (DC)-based immunotherapy. Using CD25, Foxp3, CD127 and HLA-DR as Treg associated markers, we observed increased Treg frequencies in patients at the late melanoma stage (stage IV) when compared to healthy donors. Accumulation of Tregs in patients with progressed melanoma correlated with a general reduction of T-cell responsivene…

Effects of Regulatory T Cell–Dendritic Cell Interactions on Adaptive Immune Responses

2014

The limited efficacy of chemo- or radiotherapy against neoplasias necessitates the development of complementary therapeutic strategies. Tumor immunotherapy represents a promising approach as it harnesses the potential of the host immune system to recognize and eradicate transformed cells. So far, T cell-based immunotherapy still suffers from a striking discrepancy between the induction of tumor-specific immune responses in experimental settings and therapeutic immunity in clinically relevant conditions. However, therapeutic approaches targeting immune regulatory mechanisms have lately shown encouraging results and have initiated long-lasting tumor control in patients. Therefore, a deeper un…

Mast cells counteract regulatory T-cell suppression through interleukin-6 and OX40/OX40L axis toward Th17-cell differentiation

2009

Abstract The development of inflammatory diseases implies inactivation of regulatory T (Treg) cells through mechanisms that still are largely unknown. Here we showed that mast cells (MCs), an early source of inflammatory mediators, are able to counteract Treg inhibition over effector T cells. To gain insight into the molecules involved in their interplay, we set up an in vitro system in which all 3 cellular components were put in contact. Reversal of Treg suppression required T cell–derived interleukin-6 (IL-6) and the OX40/OX40L axis. In the presence of activated MCs, concomitant abundance of IL-6 and paucity of Th1/Th2 cytokines skewed Tregs and effector T cells into IL-17–producing T cel…

2013

Dendritic cells (DC) are sentinels of immunity, essential for homeostasis of T cell-dependent immune responses. Both functions of DC, initiation of antigen-specific T cell immunity and maintenance of tissue-specific tolerance originate from distinct stages of differentiation, immunogenic versus tolerogenic. Dependent on local micro milieu and inflammatory stimuli, tissue resident immature DC with functional plasticity differentiate into tolerogenic or immunogenic DC with stable phenotypes. They efficiently link innate and adaptive immunity and are ideally positioned to modify T cell-mediated immune responses. Since the T cell stimulatory properties of DC are significantly influenced by thei…

Immunological and pathological status of gilthead sea bream (Sparus aurata L.) under different long-term feeding regimes

2003

The possible influence of the feeding regime (FR) on the immune system and pathological status of gilthead sea bream was studied. Two growth trials were performed starting at different seasons (trial 1 = March; trial 2 = June) under controlled experimental conditions. In both trials, FR-1 groups received a restricted amount of food, whereas FR-2 groups were fed to visual satiety. The pathology study included parasitological and bacteriological examination, and the immunological traits analysed were respiratory burst activity of head kidney leucocytes, serum lysozyme and alternative pathway complement activity (ACH50). The immunological status of gilthead sea bream not only was not impaired …

Confinement stress in sea bass (Dicentrarchus labrax) depresses peritoneal leukocyte cytotoxicity

2002

Fish respond to stressful conditions via neuroendocrine responses (primary response) which result in increased levels of plasma cortisol which is considered immunosuppressive. Sea bass were confined at low (10 kg/m3) and high (60 kg/m3) density for 3-48 h. Plasma cortisol and glucose were evaluated and two principal cellular immune responses were assayed. A significant increase in plasma cortisol and glucose levels, as well as osmolarity, was found following stress. In addition, phagocytic activity, as shown by reactive oxygen species (ROS) production by challenged head kidney phagocytes and cytotoxic activity of eosinophilic granule cells from peritoneal cavity against K562 tumour cell lin…

Aroclor 1254 inhibits the chemiluminescence response of peritoneal cavity cells from sharpsnout sea bream (Diplodus puntazzo)

2014

Chronic exposure to polychlorinated biphenyls (PCBs) affect the immune system of fish and could lead to a decreased disease resistance. The effects of Aroclor 1254, PCB mixtures, on the Diplodus puntazzo innate immunity were examined by assaying the zymosan stimulated chemiluminescence response (CL) of peritoneal cavity cells (PCCs) at various times (1, 24, 48 h and 1-4 weeks) from intraperitoneal injection of the xenobiotic (1 mg kg(-1) body weight). Controls were performed by assaying cells from medium-treated fish. Since the kinetic of the chemiluminescence response showed the highest peak at 25 min after the zymosan stimulation of the cells, the values found at that time were considered…

Neuroinflammation by cytotoxic T-lymphocytes impairs retrograde axonal transport in an oligodendrocyte mutant mouse.

2012

Mice overexpressing proteolipid protein (PLP) develop a leukodystrophy-like disease involving cytotoxic, CD8+ T-lymphocytes. Here we show that these cytotoxic T-lymphocytes perturb retrograde axonal transport. Using fluorogold stereotactically injected into the colliculus superior, we found that PLP overexpression in oligodendrocytes led to significantly reduced retrograde axonal transport in retina ganglion cell axons. We also observed an accumulation of mitochondria in the juxtaparanodal axonal swellings, indicative for a disturbed axonal transport. PLP overexpression in the absence of T-lymphocytes rescued retrograde axonal transport defects and abolished axonal swellings. Bone marrow tr…

2013

Background To monitor viability of implanted genetically engineered and microencapsulated human stem cells (MicroBeads) in the mouse eye, and to study the impact of the beads and/or xenogenic cells on retinal integrity. Methodology/Principal Findings MicroBeads were implanted into the subretinal space of SV126 wild type mice using an ab externo approach. Viability of microencapsulated cells was monitored by noninvasive retinal imaging (Spectralis™ HRA+OCT). Retinal integrity was also assessed with retinal imaging and upon the end of the study by light and electron microscopy. The implanted GFP-marked cells encapsulated in subretinal MicroBeads remained viable over a period of up to 4 months…

Bacterial and viral infections and related inflammatory responses in chronic obstructive pulmonary disease

2021

Abstract In chronic obstructive pulmonary disease (COPD) patients, bacterial and viral infections play a relevant role in worsening lung function and, therefore, favour disease progression. The inflammatory response to lung infections may become a specific indication of the bacterial and viral infections. We here review data on the bacterial–viral infections and related airways and lung parenchyma inflammation in stable and exacerbated COPD, focussing our attention on the prevalent molecular pathways in these different clinical conditions. The roles of macrophages, autophagy and NETosis are also briefly discussed in the context of lung infections in COPD. Controlling their combined response…