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Immunostimulatory Effects (immunostimulatory + effects)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Immunostimulatory Effects of Mesenchymal Stem Cell-Derived Neurons: Implications for Stem Cell Therapy in Allogeneic Transplantations

CLINICAL AND TRANSLATIONAL SCIENCE, Issue 1 2008
Marianne D. Castillo
Abstract Mesenchymal stem cells (MSCs) differentiate along various lineages to specialized mesodermal cells and also transdifferentiate into cells such as ectodermal neurons. MSCs are among the leading adult stem cells for application in regenerative medicine. Advantages include their immune-suppressive properties and reduced ethical concerns. MSCs also show immune-enhancing functions. Major histocompatibility complex II (MHC-II) is expected to be downregulated in MSCs during neurogenesis. Ideally, "off the shelf" MSCs would be suited for rapid delivery into patients. The question is whether these MSC-derived neurons can reexpress MHC-II in a milieu of inflammation. Western analyses demonstrated gradual decrease in MHC-II during neurogenesis, which correlated with the expression of nuclear CIITA, the master regulator of MHC-II expression. MHC-II expression was reversed by exogenous IFNY. One-way mixed lymphocyte reaction with partly differentiated neurons showed a stimulatory effect, which was partly explained by the release of the proinflammatory neurotransmitter substance P (SP), cytokines, and decreases in miR-130a and miR-206. The anti-inflammatory neurotransmitters VIP and CGRP were decreased at the peak time of immune stimulation. In summary, MSC-derived neurons show decreased MHC-II expression, which could be reexpressed by IFNY. The release of neurotransmitters could be involved in initiating inflammation, underscoring the relevance of immune responses as consideration for stem cell therapies. [source]

Nasal CpG oligodeoxynucleotide administration induces a local inflammatory response in nonallergic individuals

ALLERGY, Issue 9 2009
A. Mĺnsson
Background:, We have previously demonstrated the presence of toll-like receptor 9 in the nasal mucosa of both healthy and allergic individuals. CpG motifs, found in bacterial and viral DNA, elicit strong immunostimulatory effects via this receptor. CpG is known to skew the immune system towards a T helper 1 (Th1) profile, thereby suppressing Th2-driven allergic responses. This study was designed to examine the effects of CpG administration in the human nose. Methods:, Twenty subjects, of whom 10 suffered from seasonal allergic rhinitis (AR), were challenged intranasally with CpG outside pollen season. Symptom scores, nasal airway resistance (NAR), and nasal and pulmonary nitric oxide (NO) levels were assayed prior to challenge and 30 min, 6, 24 and 48 h post challenge. The presence of leukocytes and various cytokines were analyzed in nasal lavage (NAL) fluids before and after CpG exposure. Results:, Increased NAR, nasal NO production and secretion of interleukin (IL)-1,, IL-6, and IL-8 were seen after CpG exposure. Further analysis revealed that this inflammatory response was more marked in healthy subjects than among patients with AR, although a higher basal inflammatory response was recorded in the allergic group. In vitro experiments suggest that the effects induced by CpG are mediated by epithelial cells and neutrophils. Conclusion:, Nasal administration of CpG induces a local airway inflammation, more distinct among healthy than allergic individuals. The reduced responsiveness to CpG in allergic patients might be related to the ongoing minimal persistent inflammation. Results from cytokine analyses reflect the ability of CpG to induce a pro-inflammatory Th1-like immune response. [source]

Anti-inflammatory and immunomodulatory activities of polysaccharide from Chlorella stigmatophora and Phaeodactylum tricornutum

PHYTOTHERAPY RESEARCH, Issue 6 2003
S. Guzmán
Abstract Crude polysaccharide extracts were obtained from aqueous extracts of the microalgae Chlorella stigmatophora and Phaeodactylum tricornutum. The crude extracts were fractionated by ion-exchange chromatography on DEAE-cellulose columns. The molecular weights of the polysaccharides in each fraction were estimated by gel filtration on Sephacryl columns. The crude polysaccharide extracts of both microalgae showed anti-inflammatory activity in the carrageenan-induced paw edema test. In assays of effects on the delayed hyper-sensitivity response, and on phagocytic activity assayed in vivo and in vitro, the C. stigmatophora extract showed immunosuppressant effects, while the P. tricornutum extract showed immunostimulatory effects. Copyright © 2003 John Wiley & Sons, Ltd. [source]

The protein kinase C agonist PEP005 increases NF-,B expression, induces differentiation and increases constitutive chemokine release by primary acute myeloid leukaemia cells

BRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2009
Astrid Marta Olsnes
Summary Acute myeloid leukaemia (AML) cells show constitutive release of several chemokines that occurs in three major clusters: (I) chemokine (C-C motif) ligand (CCL)2,4/chemokine (C-X-C motif) ligand (CXCL)1/8, (II) CCL5/CXCL9,11 and (III) CCL13/17/22/24/CXCL5. Ingenol-3-angelate (PEP005) is an activator of protein kinase C and has antileukaemic and immunostimulatory effects in AML. We investigated primary AML cells derived from 35 unselected patients and determined that PEP005 caused a dose-dependent increase in the release of chemokines from clusters I and II, including several T cell chemotactic chemokines. The release of granulocyte-macrophage colony-stimulating factor and hepatocyte growth factor was also increased. CCL2,4/CXCL1/8 release correlated with nuclear factor (NF)-,B expression in untreated AML cells, and PEP005-induced chemokine production was associated with further increases in the expression of the NF-,B subunits p50, p52 and p65. Increased DNA binding of NF-,B was observed during exposure to PEP005, and the specific NF-,B inhibitor BMS-345541 reduced constitutive chemokine release even in the presence of PEP005. Finally, PEP005 decreased expression of stem cell markers (CD117, CXCR4) and increased lineage-associated CD11b and CD14 expression. To conclude, PEP005 has a unique functional pharmacological profile in human AML. Previous studies have described proapoptotic and T cell stimulatory effects and the present study describes additional T cell chemotactic and differentiation-inducing effects. [source]