Search results for "Immune system"
showing 10 items of 2885 documents
Microgravity-induced alterations in signal transduction in cells of the immune system
2010
Since decades it is known that the activity of cells of the immune system is severely dysregulated in microgravity, however, the underlying molecular aspects have not been elucidated yet. The identification of gravity-sensitive molecular mechanisms in cells of the immune system is an important and indispensable prerequisite for the development of counteractive measures to prevent or treat disturbed immune cell function of astronauts during long-term space missions. Moreover, their sensitivity to altered gravity renders immune cells an ideal model system to understand if and how gravity on Earth is required for normal mammalian cell function and signal transduction. We investigated the effec…
Localization of antimicrobial peptides in the tunic of Ciona intestinalis (Ascidiacea, Tunicata) and their involvement in local inflammatory-like rea…
2011
AbstractTunicates comprising a wide variety of different species synthesize antimicrobial peptides as important effector molecules of the innate immune system. Recently, two putative gene families coding for antimicrobial peptides were identified in the expressed sequence tag database of the tunicate Ciona intestinalis. Two synthetic peptides representing the cationic core region of one member of each of the families displayed potent antibacterial and antifungal activities. Moreover, the natural peptides were demonstrated to be synthesized and stored in distinct hemocyte types. Here, we investigated the presence of these natural peptides, namely Ci-MAM-A and Ci-PAP-A, in the tunic of C. int…
Immune mediators of sea-cucumber Holothuria tubulosa (Echinodermata) as source of novel antimicrobial and anti-staphylococcal biofilm agents
2013
The present study aims to investigate coelomocytes, immune mediators cells in the echinoderm Holothuria tubulosa, as an unusual source of antimicrobial and antibiofilm agents. The activity of the 5kDa peptide fraction of the cytosol from H. tubulosa coelomocytes (5-HCC) was tested against a reference group of Gram-negative and Gram-positive human pathogens. Minimal inhibitory concentrations (MICs) ranging from 125 to 500 mg/ml were determined against tested strains. The observed biological activity of 5-HCC could be due to two novel peptides, identified by capillary RP-HPLC/nESI-MS/MS, which present the common chemical-physical characteristics of antimicrobial peptides. Such peptides were c…
Transcription Factors Controlling Innate Lymphoid Cell Fate Decisions
2014
The mucosal epithelium is in direct contact with symbiotic and pathogenic microorganisms. Therefore, the mucosal surface is the principal portal of entry for invading pathogens and immune cells accumulated in the intestine to prevent infections. In addition to these conventional immune system functions, it has become clear that immune cells during steady-state continuously integrate microbial and nutrient-derived signals from the environment to support organ homeostasis. A major role in both processes is played by a recently discovered group of lymphocytes referred to as innate lymphoid cells (ILCs) that are specifically enriched at mucosal surfaces but are rather rare in secondary lymphoid…
Tribolium castaneum Apolipophorin-III acts as an immune response protein against Bacillus thuringiensis Cry3Ba toxic activity
2013
In this study, a 2.1-fold Apolipophorin-III mRNA up-regulation was found in Tribolium castaneum larvae challenged with Bacillus thuringiensis Cry3Ba spore-crystal mixture. Knockdown of Apolipophorin-III by RNAi resulted in increased T. castaneum larvae susceptibility following Cry3Ba spore-crystal treatment, demonstrating Apolipophorin-III involvement in insect defense against B. thuringiensis. We showed that Apolipophorin-III participates in T. castaneum immune response to B. thuringiensis activating the prophenoloxidase cascade since: (i) phenoloxidase activity significantly increased after Cry3Ba spore-crystal treatment compared to untreated or Cry1Ac spore-crystal treated larvae and (ii…
Negative regulators of integrin activity
2012
Integrins are heterodimeric transmembrane adhesion receptors composed of α- and β-subunits. They are ubiquitously expressed and have key roles in a number of important biological processes, such as development, maintenance of tissue homeostasis and immunological responses. The activity of integrins, which indicates their affinity towards their ligands, is tightly regulated such that signals inside the cell cruicially regulate the switching between active and inactive states. An impaired ability to activate integrins is associated with many human diseases, including bleeding disorders and immune deficiencies, whereas inappropriate integrin activation has been linked to inflammatory disorders…
Preclinical immunomodulation by the probiotic Bifidobacterium breve M-16V in early life
2016
This study aimed to investigate the effect of supplementation with the probiotic Bifidobacterium breve M-16V on the maturation of the intestinal and circulating immune system during suckling. In order to achieve this purpose, neonatal Lewis rats were supplemented with the probiotic strain from the 6th to the 18th day of life. The animals were weighed during the study, and faecal samples were obtained and evaluated daily. On day 19, rats were euthanized and intestinal wash samples, mesenteric lymph node (MLN) cells, splenocytes and intraepithelial lymphocytes (IEL) were obtained. The probiotic supplementation in early life did not modify the growth curve and did not enhance the systemic immu…
Multifunctional CD4(+) T cells correlate with active Mycobacterium tuberculosis infection.
2010
Th1 CD4(+) T cells and their derived cytokines are crucial for protection against Mycobacterium tuberculosis. Using multiparametic flow cytometry, we have evaluated the distribution of seven distinct functional states (IFN-gamma/IL-2/TNF-alpha triple expressors, IFN-gamma/IL-2, IFN-gamma/TNF-alpha or TNF-alpha/IL-2 double expressors or IFN-gamma, IL-2 or TNF-alpha single expressors) of CD4(+) T cells in individuals with latent M. tuberculosis infection (LTBI) and active tuberculosis (TB). We found that triple expressors, while detectable in 85-90%TB patients, were only present in 10-15% of LTBI subjects. On the contrary, LTBI subjects had significantly higher (12- to 15-fold) proportions of…
Apoptosis and ageing.
1998
Stimulation of T cells from aged individuals leads to different kinds and/or size of responses if compared with the responses of T cells obtained from young individuals. In fact elderly is associated with a progressive decline of immune response besides an increasing incidence of autoimmune phenomena. These differences might be the result of modified cellular mechanisms controlling the immune system in the course of ageing. The apoptotic deletion of activated T cells has been proposed as the key mechanism to maintain T cell homeostasis, and in this respect CD95 (Fas antigen) seems to play a major role in this course of events. In this study we show that just collected lymphocytes from old s…
Uremic serum inhibits monocyte-dependent, but not interleukin-2-dependent steps of T cell proliferation.
1990
We examined the influence of uremic serum on antigen receptor triggered T cell proliferation in dialysis patients with impaired immune function, i.e., 12 nonresponders to hepatitis B vaccination. The dialysis patients showed a monocyte dysfunction and an increased responsiveness to interleukin 2 (IL-2) according to our previous findings. In vitro the addition of IL-2 completely reconstituted the defect. Uremic serum inhibited monocyte-dependent T cell proliferation of patients and of healthy controls. Contrary, monocyte-independent steps of T cell proliferation were not impaired by uremic serum. When IL-2 was added to cultures, the T cell proliferation in the presence of uremic serum was ev…