Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic myeloid leukaemia (CML) dendritic cells (DC) are possible candidates for inducing antileukaemic immunity. This study aimed to investigate the frequency, phenotype and function of blood-derived leukaemic DC in comparison with DC from healthy donors using flow cytometric assays and mixed leucocyte reaction (MLR). Immature leukaemic DC displayed a reduced endocytotic capacity as compared with healthy controls. Moreover, in vitro maturation of leukaemic DC was found to be deficient. Expression of CD80, CD83, CD86, and major histocompatibility complex class I and class II antigens were reduced on lipopolysaccharide (LPS)-matured leukaemic DC but were enhanced by a mixture of interleukin 1beta (IL-1beta), IL-6, tumour necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2). Upon stimulation with bacterial LPS, intracellular TNF-alpha and IL-8 production was diminished in maturing DC from CML patients. This distinct cytokine deficiency was overcome when leukaemic DC were stimulated with cytokines/PGE2. MLR showed fully functional leukaemic DC after TNF-alpha-induced maturation, but a reduced proliferative alloresponse of leukaemic peripheral blood mononuclear cells. Further, intracellular production of cytokines in CML-derived T cells was markedly reduced. These data indicated that, in CML, the maturation response of leukaemic monocyte-derived DC to a natural stimulus like LPS is abnormal and may be caused by an aberrant TNF-alpha response in these cells. Thus, TNF-alpha alone or in combination with pro-inflammatory and T-cell stimulatory cytokines should be considered as an adjuvant for DC-based immunotherapy in CML.
 ...
PMID:Phenotypic and functional deficiencies of leukaemic dendritic cells from patients with chronic myeloid leukaemia. 1249 78

We analyzed capsomeres of human papillomavirus type 16 (HPV16) consisting of the L1 major structural protein for their ability to trigger a cytotoxic T-cell (CTL) response. To this end, we immunized C57BL/6 mice and used the L1(165-173) peptide for ex vivo restimulation of splenocytes prior to analysis ((51)Cr release assay and enzyme-linked immunospot assay [ELISPOT]). This peptide was identified in this study as a D(b)-restricted naturally processed CTL epitope by HPV16 L1 sequence analysis, major histocompatibility complex class I binding, and (51)Cr release assays following immunization of C57BL/6 mice with HPV16 L1 virus-like particles (VLPs). HPV16 L1 capsomeres were obtained by purification of HPV16 L1 lacking 10 N-terminal amino acids after expression in Escherichia coli as a glutathione S-transferase fusion protein (GST-HPV16 L1 Delta N10). Sedimentation analysis revealed that the majority of the purified protein consisted of pentameric capsomeres, and assembled particles were not observed in minor contaminating higher-molecular-weight material. Subcutaneous (s.c.) as well as intranasal immunization of C57BL/6 mice with HPV16 L1 capsomeres triggered an L1-specific CTL response in a dose-dependent manner as measured by ELISPOT and (51)Cr release assay. Significant reduction of contaminating bacterial endotoxin (lipopolysaccharide) from the capsomere preparation did not diminish the immunogenicity. Antibody responses (serum and vaginal) were less robust under the experimental conditions employed. In addition, s.c. vaccination with HPV16 L1 capsomeres induced regression of established tumors expressing L1 determinants (C3 tumor cells). Our data demonstrate that capsomeres are potent inducers of CTL responses similar to completely assembled T=7 VLPs. This result is of potential relevance for the development of (combined prophylactic and therapeutic) HPV-specific vaccines, since capsomeres can be produced easily and also can be modified to incorporate heterologous sequences such as early HPV proteins.
 ...
PMID:Human papillomavirus type 16 L1 capsomeres induce L1-specific cytotoxic T lymphocytes and tumor regression in C57BL/6 mice. 1266 70

Since dendritic cells (DCs) play a critical role in establishing antigen-specific adaptive immune responses, in the past several years, therapeutic strategies using genetically modified DCs against cancer and infectious diseases have attracted increasing attention. In the present study, we demonstrated that RGD fiber-mutant adenovirus vector (AdRGD) exhibited markedly superior gene transduction efficiency in mouse bone marrow-derived DCs (mBM-DCs) compared to conventional adenovirus vector (Ad). Likewise, this vector exhibited superior major histocompatibility complex class I-restricted presentation of antigen derived from the delivered gene in mBM-DCs. In order to investigate the effect of Ad-infection on the DC-differentiation process (maturation), we used three types of AdRGD and three conventional Ad to transduce mBM-DCs. These vectors carried either no transgene, LacZ gene, or gp100 gene. Infection by any of the Ad vectors enhanced the expression of MHC class II molecules in mBM-DCs. CD80, CD86, and CD40 expression and IL-12 production were more efficient in AdRGD-infected mBM-DCs than in conventional Ad-infected cells. Contrary to our expectations, endocytotic activity of mBM-DCs decreased only slightly upon Ad-infection, whereas antigen uptake by lipopolysaccharide (LPS)-driven mature mBM-DCs was significantly impaired. However, our reverse transcription-polymerase chain reaction analysis revealed that Ad-infection resulted in the upregulation of the chemokine receptor CCR7 and downregulation of CCR6 in mBM-DCs and LPS-stimulated cells. We, therefore, concluded that Ad-infection directly influenced DC-maturation, although the effects were milder than under LPS-stimulation. In addition, this change in the immunologic properties of DCs resulted primarily from an increase in the number of Ad-particles capable of invading the cells rather than from the expression of foreign genes. AdRGD-infection caused greater induction of maturation than conventional Ad-infection, irrespective of the type of transgene inserted.
 ...
PMID:Gene transduction efficiency and maturation status in mouse bone marrow-derived dendritic cells infected with conventional or RGD fiber-mutant adenovirus vectors. 1271 12

Recent evidence suggests that in addition to their well known stimulatory properties, dendritic cells (DCs) may play a major role in peripheral tolerance. It is still unclear whether a distinct subtype or activation status of DC exists that promotes the differentiation of suppressor rather than effector T cells from naive precursors. In this work, we tested whether the naturally occurring CD4+ CD25+ regulatory T cells (Treg) may control immune responses induced by DCs in vivo. We characterized the immune response induced by adoptive transfer of antigen-pulsed mature DCs into mice depleted or not of CD25+ cells. We found that the development of major histocompatibility complex class I and II-restricted interferon gamma-producing cells was consistently enhanced in the absence of Treg. By contrast, T helper cell (Th)2 priming was down-regulated in the same conditions. This regulation was independent of interleukin 10 production by DCs. Of note, splenic DCs incubated in vitro with Toll-like receptor ligands (lipopolysaccharide or CpG) activated immune responses that remained sensitive to Treg function. Our data further show that mature DCs induced higher cytotoxic activity in CD25-depleted recipients as compared with untreated hosts. We conclude that Treg naturally exert a negative feedback mechanism on Th1-type responses induced by mature DCs in vivo.
 ...
PMID:CD4+ CD25+ regulatory T cells control T helper cell type 1 responses to foreign antigens induced by mature dendritic cells in vivo. 1287 59

Heat shock proteins (HSP) have been shown to enhance antigen processing and presentation through their association with antigenic peptides and delivery of these moieties into major histocompatibility complex class I pathways. In this study, mycobacterial Hsp65 is demonstrated to have the ability to help cross-present an exogenous protein by dendritic cells (DC) to CD8 T cells without the need for complex formation between Hsp65 and the protein. This ability of Hsp65 to enhance cross-presentation is independent of its weak stimulatory effect on DC, the latter seen only after prolonged incubation. When the effect of lipopolysaccharide contamination is abrogated, Hsp65 is unable to activate Toll-like receptor (TLR)4 in the presence of CD14 and MD2. This accounts for the inability of Hsp65 to drive maturation of DC and shows that Hsp65 is not a potent stimulator of DC. Thus, Hsp65 enhances the cross-presentation of a soluble, free antigen by DC, independent of TLR4 signaling and up-regulation of costimulatory molecules.
 ...
PMID:Mycobacterial heat shock protein 65 enhances antigen cross-presentation in dendritic cells independent of Toll-like receptor 4 signaling. 1459 28

Acute graft-versus-host disease (aGVHD) remains one of the main obstacles after allogeneic bone marrow transplantation (BMT). Using a well-established mouse BMT model in which aGVHD is induced across a haploidentical mismatch, we show that the expression of heme oxygenase-1 (HO-1) can be induced by cobalt-protoporphyrin IX (CoPP) in aGVHD target organs such as liver and bowel and that the induction of HO-1 before BMT results in improved overall survival and reduced aGVHD. Serum levels of proinflammatory cytokines were markedly reduced in CoPP-treated animals. Recipients displayed less damage to the intestinal mucosa, and this resulted in reduced serum lipopolysaccharide levels at day 6 after transplantation. Peritoneal cells and CD45(+) liver cells isolated from mice that received transplants strongly expressed HO-1 and displayed a reduction in the expression of activation markers such as CD11b, CD80, and major histocompatibility complex class I. This resulted in reduced T-cell activation ex vivo. These results demonstrate that the induction of HO-1 before high-dose conditioning protects the host in multiple ways and effectively ameliorates aGVHD.
 ...
PMID:Induction of heme oxygenase-1 before conditioning results in improved survival and reduced graft-versus-host disease after experimental allogeneic bone marrow transplantation. 1520 67

Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive CD4(+)-T-lymphotropic betaherpesvirus that causes severe human thymocyte depletion in heterochimeric SCID-hu thy/liv mice and has been implicated as a potential cofactor in the progression of AIDS. However, the mechanisms of HHV-6-mediated immunosuppression have not yet been fully elucidated. We investigated the phenotypic and functional alterations induced by HHV-6 on peripheral blood-derived human dendritic cells (DC). The infection of DC with HHV-6 A or B was nonproductive, as revealed by calibrated real-time PCR measuring the accumulation of viral genome equivalents over time. Nevertheless, preexposure to HHV-6 markedly impaired the maturation of DC driven by gamma interferon and lipopolysaccharide, as shown by the reduced surface expression of major histocompatibility complex class I molecules, HLA-DR, CD40, and CD80. Moreover, HHV-6, but not the closely related betaherpesvirus HHV-7, dramatically suppressed the secretion of interleukin-12 (IL-12) p70 by DC, while the production of other cytokines that influence DC maturation, i.e., IL-10 and tumor necrosis factor alpha, was not significantly modified. Likewise, the secretion of the CC chemokines macrophage inflammatory protein 1beta and RANTES was unaltered. Functionally, a pretreatment with HHV-6 impaired the ability of DC to stimulate allogeneic T-cell proliferation. Altogether, these data identify interference with the functional maturation of DC as a potential mechanism of HHV-6-mediated immunosuppression.
 ...
PMID:Viral replication-independent blockade of dendritic cell maturation and interleukin-12 production by human herpesvirus 6. 1570 99

We report the effects of hemicellulase-treated Agaricus blazei (ABH) on the maturation of bone-marrow-derived dendritic cells (BMDCs). ABH activated immature BMDCs, inducing up-regulation of surface molecules, such as CD40, CD80 and major histocompatibility complex class I antigens, as well as inducing allogeneic T-cell proliferation and T helper type 1 cell development. However, unlike lipopolysaccharide (LPS), ABH did not stimulate the BMDCs to produce proinflammatory cytokines, such as interleukin-12 (IL-12) p40, tumour necrosis factor-alpha, or IL-1beta. In addition, ABH suppressed LPS-induced DC responses. Pretreatment of DCs with ABH markedly reduced the levels of LPS-induced cytokine secretion, while only slightly decreasing up-regulation of the surface molecules involved in maturation. ABH also had a significant impact on peptidoglycan-induced or CpG oligodeoxynucleotide-induced IL-12p40 production in DCs. The inhibition of LPS-induced responses was not associated with a cytotoxic effect of ABH nor with an anti-inflammatory effect of IL-10. However, ABH decreased NF-kappaB-induced reporter gene expression in LPS-stimulated J774.1 cells. Interestingly, DCs preincubated with ABH and then stimulated with LPS augmented T helper type 1 responses in culture with allogeneic T cells as compared to LPS-stimulated but non-ABH-pretreated DCs. These observations suggest that ABH regulates DC-mediated responses.
 ...
PMID:Antithetical effects of hemicellulase-treated Agaricus blazei on the maturation of murine bone-marrow-derived dendritic cells. 1572 Apr 41

Mucosal tolerance to E-selectin has been shown to prevent stroke and reduce brain infarcts in experimental stroke models. However, the effective E-selectin dose range required to achieve mucosal tolerance and the precise mechanisms of neuroprotection remain unclear. We sought to examine the mechanisms of cytoprotection using gene expression profiling of tissues in the setting of mucosal tolerance and inflammatory challenge. Using spontaneously hypertensive rats (SHRs), we achieved immune tolerance with 0.1 to 5 microg E-selectin per nasal instillation and observed a dose-related anti-E-selectin immunoglobulin G antibody production. We also show the distinct patterns of gene expression changes in the brain and spleen with the different tolerizing doses and lipopolysaccharide (LPS) exposure. Prominent differences were seen with such genes as insulin-like growth factors in the brain and downregulation of those encoding the major histocompatibility complex class I molecules in the spleen. In all, mucosal tolerance to E-selectin and subsequent exposure to LPS resulted in significant tissue changes. These changes, while giving an insight to the underlying mechanisms, serve as possible targets for future studies to facilitate translation to human clinical trials.
 ...
PMID:Mucosal tolerance to E-selectin and response to systemic inflammation. 1659 22

Apigenin, one of the most common flavonoids, has been shown to possess anti-inflammatory, anticarcinogenic, and free radical-scavenging properties. However, the influence of apigenin on the immunostimulatory effects and maturation of dendritic cells (DC) remains, for the most part, unknown. In this study, we have attempted to ascertain whether apigenin influences the expression of surface molecules, dextran uptake, cytokine production, and T-cell differentiation as well as the signaling pathways underlying these phenomena in murine bone marrow-derived DC. In the presence of apigenin, CD80, CD86, and major histocompatibility complex class I and II molecules, expressions on DC were significantly suppressed, and lipopolysaccharide (LPS)-induced interleukin (IL)-12 expression was impaired. The DC proved highly efficient at antigen capture, as evidenced by the observation of mannose receptor-mediated endocytosis in the presence of apigenin. The LPS-induced activation of mitogen-activated protein kinase, the nuclear translocation of its nuclear factor-kappaB p65 subunit, and the induction of the T-helper 1 response were all impaired in the presence of apigenin, whereas the cell-mediated immune response remained normal. These findings provide new insight into the immunopharmacological functions of apigenin and its effects on DC, and they may also prove useful in the development of adjuvant therapies for individuals suffering from acute or chronic DC-associated diseases.
 ...
PMID:Apigenin inhibits immunostimulatory function of dendritic cells: Implication of immunotherapeutic adjuvant. 1678 5


<< Previous 1 2 3 Next >>