Search results for "Immune system"
showing 10 items of 2885 documents
Cancer and the microbiome : potential applications as new tumor biomarker
2015
Abstract: Microbial communities that colonize in humans are collectively described as microbiome. According to conservative estimates, about 15% of all types of neoplasms are related to different infective agents. However, current knowledge is not sufficient to explain how the microbiome contributes to the growth and development of cancers. Large and thorough studies involving colonized, diverse and complex microbiome entities are required to identify microbiome as a potential cancer marker and to understand how the immune system is involved in response to pathogens. This article reviews the existing evidence supporting the enigmatic association of transformed microbiome with the developmen…
Microbiota Depletion Promotes Human Rotavirus Replication in an Adult Mouse Model
2021
Intestinal microbiota-virus-host interaction has emerged as a key factor in mediating enteric virus pathogenicity. With the aim of analyzing whether human gut bacteria improve the inefficient replication of human rotavirus in mice, we performed fecal microbiota transplant (FMT) with healthy infants as donors in antibiotic-treated mice. We showed that a simple antibiotic treatment, irrespective of FMT, resulted in viral shedding for 6 days after challenge with the human rotavirus G1P[8] genotype Wa strain (RVwa). Rotavirus titers in feces were also significantly higher in antibiotic-treated animals with or without FMT but they were decreased in animals subject to self-FMT, where a partial re…
Distribution and phenotype of rotavirus-specific B cells induced during the antigen-driven primary response to 2/6 virus-like particles administered …
2007
AbstractSelection of mucosal sites is an important step in mucosal vaccine development. The intrarectal (IR) route represents an alternative to the oral route of immunization; nevertheless, immune responses induced by this route are not well defined. Here, we studied the early primary B cell response (induction, homing, and phenotype) induced by IR immunization with rotavirus (RV)-2/6 virus-like particles (VLP). Using flow cytometry, we traced RV-specific B cells in different lymphoid tissues and analyzed the expression of α4β7 and CCR9, which are important receptors for homing to the gut, as well as CD5, a marker expressed by B1-a cells, which are a major source of natural antibodies. We o…
Specific Recognition of the 5′-Untranslated Region of West Nile Virus Genome by Human Innate Immune System
2022
In the last few years, the sudden outbreak of COVID-19 caused by SARS-CoV-2 proved the crucial importance of understanding how emerging viruses work and proliferate, in order to avoid the repetition of such a dramatic sanitary situation with unprecedented social and economic costs. West Nile Virus is a mosquito-borne pathogen that can spread to humans and induce severe neurological problems. This RNA virus caused recent remarkable outbreaks, notably in Europe, highlighting the need to investigate the molecular mechanisms of its infection process in order to design and propose efficient antivirals. Here, we resort to all-atom Molecular Dynamics simulations to characterize the structure of th…
PKM2 promotes Th17 cell differentiation and autoimmune inflammation by fine-tuning STAT3 activation
2019
Th17 cells undergo metabolic reprogramming towards glycolysis to support their differentiation and pathogenicity. Damasceno et al. report that PKM2, a glycolytic enzyme, plays a nonmetabolic role in mediating Th17 cell differentiation and autoimmune neuroinflammation by fine-tuning STAT3 activation.
Protein kinase CK2 governs the molecular decision between encephalitogenic T H 17 cell and T reg cell development
2016
T helper 17 (TH17) cells represent a discrete TH cell subset instrumental in the immune response to extracellular bacteria and fungi. However, TH17 cells are considered to be detrimentally involved in autoimmune diseases like multiple sclerosis (MS). In contrast to TH17 cells, regulatory T (Treg) cells were shown to be pivotal in the maintenance of peripheral tolerance. Thus, the balance between Treg cells and TH17 cells determines the severity of a TH17 cell-driven disease and therefore is a promising target for treating autoimmune diseases. However, the molecular mechanisms controlling this balance are still unclear. Here, we report that pharmacological inhibition as well as genetic ablat…
Mouse models of inflammatory bowel disease.
2007
Animal models of intestinal inflammation are indispensable for our understanding of the pathogenesis of Crohn disease and Ulcerative colitis, the idiopathic forms of inflammatory bowel disease in humans. The clinical appearance of human IBD is heterogeneous, a fact that is also reflected by the steadily increasing number of mouse strains displaying IBD like intestinal alterations. The analysis of these models together with genetic studies in humans greatly enhanced our insights into immunoregulatory processes in the gut and led to the generally accepted hypothesis that a deregulated immune response against components of the intestinal microbiota is critically involved in IBD pathophysiology…
SPARC is a new myeloid-derived suppressor cell marker licensing suppressive activities
2019
Myeloid-derived suppressor cells (MDSC) are well-known key negative regulators of the immune response during tumor growth, however scattered is the knowledge of their capacity to influence and adapt to the different tumor microenvironments and of the markers that identify those capacities. Here we show that the secreted protein acidic and rich in cysteine (SPARC) identifies in both human and mouse MDSC with immune suppressive capacity and pro-tumoral activities including the induction of epithelial-to-mesenchymal transition (EMT) and angiogenesis. In mice the genetic deletion of SPARC reduced MDSC immune suppression and reverted EMT. Sparc−/− MDSC were less suppressive overall and the granu…
Induction of tolerogenic lung CD4+ T cells by local treatment with a pSTAT-3 and pSTAT-5 inhibitor ameliorated experimental allergic asthma.
2010
Signal transducer and activator of transcription (STAT)-3 inhibitors play an important role in regulating immune responses. Galiellalactone (GL) is a fungal secondary metabolite known to interfere with the binding of phosphorylated signal transducer and activator of transcription (pSTAT)-3 as well of pSTAT-6 dimers to their target DNA in vitro. Intra nasal delivery of 50 μg GL into the lung of naive Balb/c mice induced FoxP3 expression locally and IL-10 production and IL-12p40 in RNA expression in the airways in vivo. In a murine model of allergic asthma, GL significantly suppressed the cardinal features of asthma, such as airway hyperresponsiveness, eosinophilia and mucus production, after…
Dual Antimicrobial and Antiproliferative Activity of TcPaSK Peptide Derived from a Tribolium castaneum Insect Defensin
2021
Antimicrobial peptides (AMPs) found in the innate immune system of a wide range of organisms might prove useful to fight infections, due to the reported slower development of resistance to AMPs. Increasing the cationicity and keeping moderate hydrophobicity of the AMPs have been described to improve antimicrobial activity. We previously found a peptide derived from the Tribolium castaneum insect defensin 3, exhibiting antrimicrobial activity against several human pathogens. Here, we analyzed the effect against Staphyloccocus aureus of an extended peptide (TcPaSK) containing two additional amino acids, lysine and asparagine, flanking the former peptide fragment in the original insect defensi…