The immune-regulatory B7-H1 receptor, also known as programmed death-ligand 1 (PD-L1), plays an important role in cell-mediated immune response. It is a co-signaling molecule that mediates regulation ...of T cell activation and tolerance and is able to negatively regulate activated T cell functions and survival. High expression of B7-H1 in host cells may contribute to the chronicity of inflammatory disorders and represents a possible mechanism of immune evasion. Porphyromonas gingivalis is regarded as a keystone pathogen in periodontitis and is able to invade host cells and disposes a variety of virulence factors including lipopolysaccharide (LPS), fimbriae and proteases such as gingipains. Based on previous studies that demonstrated the capability of P. gingivalis to induce up-regulation of PD-L1 in malignant and non-malignant oral epithelial cells, the aim of the present work was to analyse the potential of various cellular components of P. gingivalis to induce the PD-L1 receptor. Human squamous carcinoma cells and primary gingival keratinocytes were stimulated with total, inner and outer membrane fractions, cytosolic proteins, as well as LPS and peptidoglycans. PD-L1 protein expression was investigated by Western blot analysis and RT-PCR. It was demonstrated that the total membrane fraction induced the highest up-regulation in B7-H1 expression, followed by the outer and inner membrane, whereas cytosolic proteins and LPS did not. In conclusion, we provide evidence that the membrane fraction of P. gingivalis is responsible for up-regulation of the immune-regulatory receptor PD-L1 in squamous carcinoma cells and gingival keratinocytes, and thus may support immune evasion of oral carcinomas.
Abstract The immune-regulatory B7-H1 receptor, also known as programmed death-ligand 1 (PD-L1), plays an important role in cell-mediated immune response. It is a co-signaling molecule that mediates ...regulation of T cell activation and tolerance and is able to negatively regulate activated T cell functions and survival. High expression of B7-H1 in host cells may contribute to the chronicity of inflammatory disorders and represents a possible mechanism of immune evasion. Porphyromonas gingivalis is regarded as a keystone pathogen in periodontitis and is able to invade host cells and disposes a variety of virulence factors including lipopolysaccharide (LPS), fimbriae and proteases such as gingipains. Based on previous studies that demonstrated the capability of P. gingivalis to induce up-regulation of PD-L1 in malignant and non-malignant oral epithelial cells, the aim of the present work was to analyse the potential of various cellular components of P. gingivalis to induce the PD-L1 receptor. Human squamous carcinoma cells and primary gingival keratinocytes were stimulated with total, inner and outer membrane fractions, cytosolic proteins, as well as LPS and peptidoglycans. PD-L1 protein expression was investigated by Western blot analysis and RT-PCR. It was demonstrated that the total membrane fraction induced the highest up-regulation in B7-H1 expression, followed by the outer and inner membrane, whereas cytosolic proteins and LPS did not. In conclusion, we provide evidence that the membrane fraction of P. gingivalis is responsible for up-regulation of the immune-regulatory receptor PD-L1 in squamous carcinoma cells and gingival keratinocytes, and thus may support immune evasion of oral carcinomas.
Langkap (Arenga obtusifolia) is one of the species of the Arenga clan, which has a wide distribution in Ujung Kulon National Park (UKNP). The aim of study was to determine the pattern of spreading ...langkap in order to support the management of Javan Rhino habitat. The vegetation analysis method used is a combination method between the line method and the path method. Langkap is the dominant species in UKNP at the sapling growth rate, with a density of 480-624 individuals/ha and INP value of 61.47% -78.30%, while the catch density at seedling growth rate is 900- 2,200 individuals/ha with INP value of 21.31% -49.41%. The standard Morisita coefficient value of langkap in each research block and growth rate is obtained in the range of values (-0.32) - 0.51, the spreading pattern shows a clustered spread pattern (Ip> 0) and uniform (Ip <0). The tendency of langkap domination in the research block can be seen from the ratio of catch density compared to the total density or its relative density at various growth rates. This shows that in the dominant catchment area there is a reduction in the density of plants other than langkap, especially the Javan Rhino feed plants.
The eggs of the parasitic trematode Schistosoma mansoni are powerful inducers of a T helper type 2 (Th2) immune response and immunoglobulin E (IgE) production. S. mansoni egg extract (SmEA) ...stimulates human basophils to rapidly release large amounts of interleukin (IL)-4, the key promoter of
a Th2 response. Here we show purification and sequence of the IL-4-inducing principle of S. mansoni eggs (IPSE). Stimulation studies with human basophils using SmEA fractions and natural and recombinant IPSE as well as neutralization
and immunodepletion studies using antibodies to recombinant IPSE demonstrate that IPSE is the bioactive principle in SmEA
leading to activation of basophils and to expression of IL-4 and IL-13. Regarding the mechanism of action, blot analysis showed
that IPSE is an IgE-binding factor, suggesting that it becomes effective via cross-linking receptor-bound IgE on basophils.
Immunohistology revealed that IPSE is enriched in and secreted from the subshell area of the schistosome egg. We conclude
from these data that IPSE may be an important parasite-derived component for skewing the immune response toward Th2.
During a paleoparasitological survey of several animal mummies ( Cavia
aperea f. porcellus and Canis familiaris ) from Chiribaya Baja, an
archaeological site in Southern Peru, an unexpected find was ...made. In
the well preserved fur, large numbers of mummified fleas (Pulex
simulans/irritans) that parasitized the animals during life were
encountered. Due to the relative recent event of the host mummification
and the outstanding preservation of the fleas, an attempt for the
retrieval of DNA was made. A DNA extraction and sequencing protocol for
archaeological ectoparasitic remains has been established, taking
additional studies for tissue and protein preservation into account.
Tissue preservation was assessed with transmission electron microscopy
and the protein preservation was tested through the racemisation ratios
of aspartic acid. Regions of the 28S rDNA gene were successfully
amplified and sequenced. Further research perspectives are outlined.
Javan rhino (Rhinoceros sondaicus Desmarest 1822) is the rarest species among 5 species of rhinos in the world. Its distribution is currently limited only in Ujung Kulon National Park (UKNP), ...Indonesia. Due to the small population size and its limited distribution, it is listed as critically endangered species in the IUCN Redlist. The main objectives of this research were: 1) to identify the dominant habitat components that determine the presence of javan rhino in UKNP; 2) to analyze habitat suitability of javan rhino (Rhinoceros sondaicus Desmarest 1822) in UKNP using geographical information system; and 3) to examine its habitat condition. Results of the research found eight components identified to be crucial for Javan rhino habitat and appropriate for spatial modelling of habitat suitability, of which four were the most dominant factors influencing the frequency of javan rhino presence. These four dominants factors were slope, distance from wallow sites, distance from rumpang (open area), and distance from beach.
We sought to examine coronary arteries for the presence of viable bacteria of the fastidious species Chlamydia pneumoniae.
The respiratory pathogen C. pneumoniae has been implicated in the ...pathogenesis of coronary artery disease (CAD). Previous studies have demonstrated an antichlamydial seroresponse to be a cardiovascular risk factor and coronary atheromata to contain chlamydial components in varying proportions. Endovascular demonstration of replicating bacteria is required to provide evidence for an infectious component in CAD and a rationale to discuss antimicrobial therapy.
Myocardial revascularization was performed in 70 patients. Atherosclerotic lesions from 53 coronary endarterectomy and 17 restenotic bypass samples were cultured and subjected to nested polymerase chain reaction (PCR) for C. pneumoniae. Antichlamydial immunoglobulin G (IgG), IgA and IgM was examined by microimmunofluorescence.
Viable C. pneumoniae was recovered from 11 (16%) of 70 atheromata, and chlamydial deoxyribonucleic acid (DNA) was detected in 21 (30%) of 70 atheromata; 17 nonatherosclerotic control samples were PCR-negative (p < 0.01). Fifteen (28%) of 53 endarterectomy and 6 (35%) of 17 bypass samples were PCR-positive. DNA sequencing of six different PCR products did not reveal differences between coronary isolates and respiratory reference strains, suggesting that common respiratory strains gain access to the systemic circulation. Serologic results did not correlate with direct detection results and did not identify individual endovascular infection.
A significant proportion of atherosclerotic coronary arteries harbor viable C. pneumoniae. This finding supports the hypothesis of a chlamydial contribution to atherogenesis. Whether chlamydiae initiate atherosclerotic injury, facilitate its progression or colonize atheromata is unknown. However, the endovascular presence of viable bacteria justifies a controlled clinical investigation of antimicrobial treatment benefit in the therapy and prevention of CAD.
Chlamydiae possess a genus-specific epitope that is located on the lipopolysaccharide (LPS) and is composed of a 3-deoxy-D-manno-octulosonic acid (Kdo) trisaccharide of the sequence alpha ...Kdo-(2-->8)--alpha Kdo-(2-->4)-alpha Kdo. In Chlamydia trachomatis, this trisaccharide is biosynthetically generated through the action of a multi-functional Kdo-transferase encoded by the gene gseA. gseA of Chlamydia psittaci 6BC was cloned and expressed in a rough mutant (Re chemotype) of Escherichia coli (strain F515) that contains an LPS with only two alpha 2-->4-linked Kdo residues. Recombinant strains were able to add the immunodominant Kdo residue in alpha 2-->8-linkage to the parental LPS, as determined by SDS-PAGE and Western blot analysis using a monoclonal antibody against the genus-specific epitope. The DNA sequence of gseA was determined and aligned to that published recently for C. trachomatis serovar L2. Most surprisingly, the two deduced amino acid sequences shared only an overall homology of 67%. Thus, gseA exhibits species specificity at the DNA level, whereas its gene product results in the synthesis of a carbohydrate antigen with genus specificity.
Endotoxins of Gram-negative microbes fulfill as components of the outer membrane a vital function for bacterial viability and, if set free, induce in mammalians potent pathophysiological effects. ...Chemically, they are lipopolysaccharides (LPS) consisting of an O-specific chain, a core oligosaccharide, and a lipid component, termed lipid A. The latter determines the endotoxic activities and, together with the core constituent Kdo, essential functions for bacteria. The primary structure of lipid A of various bacterial origin has been elucidated and lipid A of Escherichia coli has been chemically synthesized. The biological analysis of synthetic lipid A partial structures proved that the expression of endotoxic activity depends on a unique primary structure and a peculiar endotoxic conformation. The biological lipid A effects are mediated by macrophage-derived bioactive peptides such as tumor necrosis factor alpha (TNF). Macrophages possess LPS receptors, and the lipid A regions involved in specific binding and cell activation have been characterized. Synthetic lipid A partial structures compete the specific binding of LPS or lipid A and antagonistically inhibit the production of LPS-induced TNF. LPS toxicity, in general, and the ability of LPS to induce TNF are also suppressed by a recently developed monoclonal antibody (IgG2a), which is directed against an epitope located in the core oligosaccharide. At present we determine molecular and submolecular details of the specificity of the interaction of lipid A with responsive host cells with the ultimate aim to provide pharmacological or immunological therapeutics that reduce or abolish the fatal inflammatory consequences of endotoxicosis.
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