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

We have purified extrachromosomal circular DNAs from adult mouse spleen cells, and cloned into a phage vector the BamHl fragments hybridizing with C mu and S gamma 1 probes. We obtained 52 S mu+S gamma 1+ clones by screening 1.4 million phage clones derived from spleen cells stimulated with bacterial lipopolysaccharide and interleukin 4. We have identified the breakpoints of six clones that contain S gamma 1 and S mu sequences fused in the 5' to 3' orientation. All these switch recombination sites were assigned to the central repetitive sequences of the S mu and S gamma 1 regions. Since the common S mu-S gamma 1 sequences at the recombination sites are at most 2 bases long, typical homologous recombination cannot account for their joining. These findings provide direct evidence that mu-gamma 1 class switching can occur by the looping out and excision of chromosomal DNA, with formation of a circle.
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PMID:Circular DNA is excised by immunoglobulin class switch recombination. 236 32

Human macrophages obtained from circulating monocytes matured in vitro by culture for seven days in hydrophobic flexible teflon bags were successfully fused with murine myeloma NS1 cells. Six of 20 clones, selected for their adherence properties, were further studied. All possessed human chromosomes (mean number ranging from 4 to 14 depending on the clones studied), exhibited non-specific esterases (but no peroxidase activity) and expressed CD14 antigen and C3 receptors (but no MAX-1 antigen). Moreover, the hybridomas retained phagocytic activity and high interferon plus lipopolysaccharide-activable cytolytic activity against tumor cells.
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PMID:Establishment and characterization of somatic hybrids between human differentiated macrophages and mouse myeloma NS1 cells. 240 83

Serogroup-specificity of Legionella pneumophila is related to lipopolysaccharide (LPS), and few cross-reactions between serogroups have been observed with rabbit or monkey antisera. C57BL/6 mice were sequentially immunized with crude outer membrane fractions of L. pneumophila serogroups 1, 5, and 7, Legionella bozemanii, and Legionella micdadei. Spleen cells from these mice were then fused with the Sp2-0/Ag14 mouse myeloma cell line. Outer membrane-rich fractions and LPS were prepared from L. pneumophila serogroups 1 to 8 and other Legionella and non-Legionella species. Immunoblots of these extracts were performed with monoclonal antibody obtained from these fusions. One of these monoclonal antibodies recognized an epitope common to all tested serogroups of L. pneumophila and attached to the major constituent of the outer membrane, LPS. This antibody did not react with other Legionella species and numerous gram-negative rods other than Pseudomonas fluorescens CDC93. This monoclonal antibody may be useful in preliminary identification of L. pneumophila as an alternative to direct fluorescent-antibody testing.
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PMID:Common epitope on the lipopolysaccharide of Legionella pneumophila recognized by a monoclonal antibody. 245 35

The current work was undertaken in order to assess the role of the monoclonal antibodies (Mabs) to lipopolysaccharide (LPS) of Salmonella typhi in the induction of passive protection against the challenge with the bacteria in a mice model. BALB/c mice were immunized with the whole bacteria, mice with high anti-LPS antibody titers were killed, the spleens were removed and splenocytes were fused with the mouse plasmocytoma SP2/0. Two IgM monoclonal antibodies against porins were developed. Each one of these Mabs recognized the polysaccharide region of LPS. Passive immunization with supernatant fluid of mice with one of these monoclonal antibodies did not protect against challenged with 20 LD50 and 100 LD50 of Salmonella typhi. The results suggest that LPS is not valuable immunogen for the induction of a protective status against typhoid fever.
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PMID:[Monoclonal antibodies against the lipopolysaccharide of Salmonella typhi 9,12,VI:d. Analysis of passive protection in a mouse model of typhoid fever]. 248 71

A hybridoma line secreting a human monoclonal antibody (HMAb) capable of recognizing Fisher immunotype (IT) 1, 3, 4, and 6 lipopolysaccharide (LPS) in vitro was isolated. Peripheral blood lymphocytes (PBL) were obtained from volunteers immunized with an experimental Pseudomonas aeruginosa O polysaccharide-toxin A vaccine. PBL-expressing surface antibodies able to bind to P. aeruginosa LPS were isolated by adsorption onto LPS-coated plastic wells. Such PBL were transformed with Epstein-Barr virus. Lymphoblastoid cell lines secreting anti-P. aeruginosa LPS antibodies were identified by an enzyme-linked immunosorbent assay and fused to the F3B6 heteromyeloma line. A hybridoma line producing a HMAb (2-8AH79) able to bind IT-1, IT-3, IT-4, and IT-6 LPS was identified by an enzyme-linked immunosorbent assay. This HMAb was found to bind to the O-polysaccharide regions of IT-1, IT-3, IT-4, and IT-6 LPS, as determined by immunoblotting. By using an immunofluorescence microscopy assay, the cell surfaces of IT-3 and IT-4 bacteria were strongly stained by HMAb 2-8AH79, whereas those of IT-1 and IT-6 bacteria were weakly stained. This HMAb was found to promote the uptake and killing of IT-3 and IT-4 bacteria, but not IT-1 or IT-6 organisms, by human polymorphonuclear leukocytes. Similarly, the passive transfer of HMAb 2-8AH79 to mice afforded significant protection only against a challenge with IT-3 and IT-4 bacteria.
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PMID:Isolation and characterization of a human monoclonal antibody that recognizes epitopes shared by Pseudomonas aeruginosa immunotype 1, 3, 4, and 6 lipopolysaccharides. 250 71

Splenic B cells of A/J mice immunized with 2,4,6-trinitrophenyl (TNP)-lipopolysaccharide were fused with 2.52M, a mutant of a B cell line, in the presence of polyethylene glycol and dimethyl sulfoxide. TP67.21, a subclone of a resulting hybridoma, expresses IAk, IEk, IgM, B220, P50, and receptors for C3 fragment of complement, the Fc portion of IgG, and interleukin 2 receptor on the cell membrane; it also possesses receptor molecules for TNP on its surface, derived from TNP-reactive B cells of A/J mice primed with TNP-lipopolysaccharide used for somatic hybridization, by a rosette-forming assay with TNP-sheep erythrocytes. In contrast, parental 2.52M lacks IAk and IEk on the cell membrane and does not bind to TNP-sheep erythrocytes under the same conditions. Thus, it is likely that TP67.21 is an antigen-specific B cell clone directed against TNP. The antigen binding of cells was markedly inhibited by the specific free hapten or anti-IgM antibodies. Interestingly, TP67.21 was induced to generate a significant amount of anti-TNP antibody when treated with TNP conjugates including T cell-independent and -dependent antigens, such as TNP-lipopolysaccharide, TNP-bovine serum albumin, TNP-ovalbumin, and TNP-keyhole limpet hemocyanine in the absence of T cell help, as well as polyclonal activators; this was followed by a marked decrease in the expression of B cell surface markers on the cell membrane. This suggests that the cross-linkage of receptor molecules on TP67.21 by antigen may directly provide a differentiative signal for maturation to a lineage of B cells, and consequently results in the generation of antigen-specific antibodies without T cell involvement.
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PMID:Establishment of an antigen-specific B cell clone by somatic hybridization. 282 Nov 18

The cDNA for human beta 2-interferon (IFN-beta 2)/B-cell differentiation factor 2/hepatocyte-stimulating factor was expressed in Escherichia coli to yield a fusion protein which contains the 182 carboxyl-terminal amino acids of IFN-beta 2 fused to a 34-amino acid prokaryotic leader peptide (rIFN-beta 2). When added to cultures of human hepatoma cell line Hep3B2, rIFN-beta 2 as well as preparations of natural IFN-beta 2 enhance secretion of positive acute phase reactants such as alpha 1-antichymotrypsin, complement C3, fibrinogen, and alpha 1-acid glycoprotein and inhibit secretion of albumin, confirming that a protein derived from the IFN-beta 2 gene can have hepatocyte-stimulating factor activity. We have prepared a rabbit polyclonal antiserum to the E. coli-derived human IFN-beta 2 fusion protein. This polyclonal antiserum inhibits the hepatocyte-stimulating and B-cell differentiation activities of appropriate IFN-beta 2 preparations. The anti-rIFN-beta 2 antiserum has been used in immunoprecipitation experiments and in Western blots to help define the secretory proteins derived from the IFN-beta 2 gene in fibroblasts and monocytes. "Uninduced" human FS-4 fibroblasts as well as those induced with interleukin-1 alpha, tumor necrosis factor, or bacterial lipopolysaccharide secrete at least five forms of IFN-beta 2 of apparent molecular mass in the range from 23 to 30 kDa which can be resolved by polyacrylamide gel electrophoresis under denaturing and reducing conditions. The three higher molecular mass forms are not observed when FS-4 cells are induced in the presence of tunicamycin, suggesting that these forms are N-glycosylated (gp28, gp29, and gp30). Although secretion of the two lower molecular mass forms is resistant to tunicamycin, they are labeled by [3H]glucosamine (gp23-gp25). The inclusion of cycloheximide during the [35S]methionine labeling of induced FS-4 cells results in the preferential synthesis and secretion of the 29-kDa triplet. Human monocytes induced with bacterial lipopolysaccharide also secrete several distinct forms of IFN-beta 2 in the size range from 23 to 30 kDa which co-migrate in polyacrylamide gels with those obtained from FS-4 cells. Our observations help relate previous descriptions of multiple forms of hepatocyte-stimulating factor to specific proteins derived from the IFN-beta 2 gene.
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PMID:Synthesis and secretion of multiple forms of beta 2-interferon/B-cell differentiation factor 2/hepatocyte-stimulating factor by human fibroblasts and monocytes. 313 26

An in vitro stimulation protocol has been established which allows production of IgG-secreting murine hybridomas. This procedure has been examined using jack bean urease and human luteinizing hormone as antigens. Parameters which have been optimized include selection of media and serum supplements, thymocyte-conditioned media, antigen dosage, length of stimulation and the effect of medium changes during stimulation and additions of polyclonal mitogen. Murine spleen cells (1 X 10(8) in 10 ml) were incubated with varying doses of jack bean urease and human luteinizing hormone in a six-well plate in supplemented DMEM with 5% normal rabbit serum and 10% thymocyte-conditioned media. Following 5 and/or 8 days stimulation, the spleen cells were fused with SP2/0 cells and plated in 96-well plates. Stable hybridomas were obtained for both antigens from over 25% of the wells identified in initial screening for specific antibody production. All monoclonal antibodies obtained in the LH stimulation experiments, with one exception, were of the IgM isotype. A large number of IgG-producing hybridomas were isolated following prolonged (8 day) stimulation with high concentrations of urease, during which time the medium remained unchanged. Addition of polyclonal mitogen (E. coli lipopolysaccharide) at 10 micrograms/ml markedly increased the production of hybridomas secreting anti-urease, but most were of IgM class.
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PMID:Production of IgG-producing hybridomas by in vitro stimulation of murine spleen cells. 349 63

Phytohaemagglutinin (PHA) receptor glycoproteins purified by affinity chromatography from porcine splenic lymphocytes, were reconstituted into vesicles made of phosphatidylcholine and phosphatidylserine, concomitantly with Sendai virus fusogenic proteins HN and F. The vesicles were used as a vehicle to insert the PHA receptor glycoproteins into a highly enriched population of porcine B lymphocytes. Fluorescence analyses showed that 52 +/- 2% of the reconstituted B cells had incorporated the lectin receptors. The modified B lymphocytes were assayed for their response (tritiated thymidine incorporation into nucleic acids) to PHA, concanavalin A (Con A), or to lipopolysaccharide (LPS). The results showed that porcine B cells fused with vesicles containing only viral fusogenic proteins failed to respond to either PHA or Con A. Tritiated thymidine incorporation was similar to background values. The cells did, however, respond to LPS with values of label incorporation similar to those observed in the case of pre-fused B lymphocytes. When purified B lymphocytes were fused with vesicles containing PHA receptors and viral fusogenic proteins, assays of thymidine incorporation showed a statistically significant (P less than 0.001) and specific response of the modified cells to PHA stimulation. Reconstituted cells cultured in the presence of PHA incorporated approximately nine times more radioactive label than pre-fused cells or cells fused with vesicles containing only fusogenic viral proteins. In marked contrast, reconstituted B lymphocytes did not show any significant label incorporation above background level in response to Con A, but they retained their ability to respond to LPS. Our findings suggest that B lymphocytes can be made to respond specifically to PHA by insertion of appropriate lymphocyte-derived receptors.
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PMID:B lymphocytes respond specifically to phytohaemagglutinin after liposome-dependent transfer of purified phytohaemagglutinin receptors. 349 68

Metallothioneins are a family of ubiquitous, cysteine rich proteins, whose amino acidic and genomic sequences have been highly conserved during evolution. MT synthesis is induced by heavy metals, glucocorticoids and a bacterial lipopolysaccharide in vivo and in vitro. MT forms stable complexes with heavy metals. One MTIIA gene, four MTI class genes and five pseudogenes have been isolated in humans. The cluster of MT genes is located on chromosome 16. The cloned, transfected genes retain metal inducibility. The first 150 bp of the 5' flanking region of mouse and human MT genes are essential for transcription and metal regulation. Two control regions have been identified. The distal region, between -151 and -78 is essential for efficient transcription and binding of cellular factor(s) which regulates MT gene expression. In Menkes' disease, a lethal X-linked recessive disorder, copper accumulates intracellularly bound to MT. Low doses of copper induce MT synthesis in Menkes' fibroblasts, but not in normal controls. Transfection experiments using the mouse MTI promoter fused to CAT show that the effect of copper in MT transcription is in trans. Menkes' cells are more sensitive to copper than normal controls and respond to copper poisoning by synthesizing two heat-shock like proteins. A mutation affecting copper transport or metabolism is discussed.
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PMID:Metallothionein gene regulation in Menkes' disease. 353 Sep 53


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