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 analyzed by the limiting dilution assay on spleen cells from (NZB x NZW)F1 hybrid mice the repertoire of lipopolysaccharide-responsive murine kappa- and lambda 1-secreting B cells committed to the production of anti-DNA autoantibodies to determine the contribution of the heavy and light chains to anti-DNA specificities. Our results demonstrated that anti-DNA precursors were predominantly found in the kappa-secreting B cell population, but not in lambda 1-secreting B cells, while anti-hapten, dinitrophenyl, and anti-tetanus toxoid activities were distributed fairly well in both populations of B cells. This suggests that the V kappa gene segments are critically involved in the generation of anti-DNA specificities, and that at least at the germ-line gene level, the heavy chain V region genes by themselves are not able to confer the anti-DNA autoreactivity.
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PMID:Lack of anti-DNA precursors in lambda chain-bearing B lymphocytes in (NZB x NZW)F1 mice. Evidence for the contribution of V kappa genes to anti-DNA specificity. 190 Dec 68

The expression of kappa and lambda light chains in surface immunoglobulin (sIg) molecules on B lymphocytes differentiating from murine pre-B cell clones in vitro was analyzed. The four pre-B cell clones used represent a very early pre-B cell stage. They have their heavy chain loci DJ rearranged and their light chain loci in germ-line configuration. In order to grow in vitro, these clones require contact with stromal cells and the stimulatory activity of interleukin (IL) 7. Upon removal of IL 7 from the cultures, these clones differentiate within 3 days into sIg+ B cells. Between 7% and 12% of IgM+ B cells could be detected in these cultures. The majority (78%-92%) of the IgM+ B cells co-expressed kappa light chains. The percentage of lambda light chain expressing B cells was below detectable level. Upon lipopolysaccharide (LPS) stimulation, the percentages of IgM+ B cells increased dramatically (from 32%-64%). The majority (91%-97%) of the IgM+ B cells express kappa chains, but a very small percentage (3.1%-5.0%) express lambda. A similarly high kappa/lambda ratio was found in 418 hybridomas prepared from these LPS-stimulated B cells (388 kappa+ and 30 lambda+). Thus, the high kappa/lambda ratio characteristic of the mouse peripheral B cell repertoire is already evident in the antigen-independent transition from pre-B to B cells.
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PMID:The kappa/lambda ratio in surface immunoglobulin molecules on B lymphocytes differentiating from DHJH-rearranged murine pre-B cell clones in vitro. 193 27

Primary antigenic exposure results in an initial antibody response and the T cell-dependent induction of B-cell memory. Memory B-cell differentiation is characterized by somatic hypermutation in antibody variable region genes (V) and selection of B cells expressing high-affinity variants of this antigen receptor. Despite our current understanding of B-cell memory, the origin of memory B cells and the regulation of their differentiation remain elusive. This is largely due to the difficulties in observing and purifying this minor component of the immunized spleen. Further, molecular characterization of memory B cells requires hybridoma formation which restricts analyses to only those clones capable of fusion and does not allow isolation of cells in a normal physiological state. We have therefore developed a unique system which allows isolation and unambiguous enumeration of IgG1+ memory B cells, based on six-parameter flow cytometry, secretion of antibody in clonal cultures and analysis of clonally expressed V genes using the polymerase chain reaction. Here we report that single IgG1+ antigen-binding B cells from an early secondary immune response proliferate in lipopolysaccharide-driven microcultures and produce antigen-specific IgG1 antibodies. Individual B-cell clones in these cultures express somatically mutated heavy chain V genes, confirming their designation as memory B cells. Although isolated memory B cells undergo extensive proliferation in vitro, V gene sequence analysis of their individual progeny shows that further hypermutation does not occur.
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PMID:Molecular characterization of single memory B cells. 201 51

Initiation of the immunoglobulin heavy chain switch DNA rearrangement event is thought to involve conversion of the target switch region DNA to an accessible state. Accessibility is likely to be mediated by the binding of regulatory proteins to sequences in or near switch regions. A DNase hypersensitivity assay was used to recognize possible regions of protein binding in the gamma 1 switch region of the B cell hybridoma 470.25. A strong DNase hypersensitive site was identified 5' of the tandemly repeated S gamma 1 sequences. Data from other laboratories suggest that this hypersensitive site is associated with switch recombination to gamma 1. However, the 470.25 cell does hypersensitive sites within the repetitive portion of the gamma 1 switch region was also identified. A gel retardation assay for protein--DNA interaction revealed a sequence present in several copies in the gamma 1 switch region that specifically binds nuclear proteins. This binding sequence, SG1BS, contains the octanucleotide sequence ATGCAAAA, a 7/8 match to the transcriptional enhancer octamer motif found in immunoglobulin promoters and the heavy chain enhancer. Binding competition studies of SG1BS demonstrate that both the octamer and flanking sequences are critical for binding. By size- and tissue-distribution, the factors that bind SG1BS are not distinguishable from the previously identified octamer-binding factors OTF-1 and OTF-2. The ability of proteins to bind the S gamma 1 octamer motif is increased 2.3-fold upon IL-4 induction of lipopolysaccharide-stimulated B cells.
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PMID:Nuclear protein binding to octamer motifs in the immunoglobulin gamma 1 switch region. 202 12

The penta-deca (pd) promoter element from the SP6 kappa promoter and the muE2 box from the Ig heavy chain intron enhancer were analysed in an electrophoretic mobility shift assay (EMSA), utilising cell extracts from total mouse splenic B cells before and after stimulation with lipopolysaccharide. With both probes a changed EMSA pattern was observed after stimulation of the cells, where higher molecular weight DNA/protein complexes became dominant. When the pd and muE2 sequence elements were cloned in front of a TATA box and analysed for their transcriptional promoting activity in lipopolysaccharide stimulated B cells, they were inactive. On the contrary, the same constructs were transcriptionally active in some but not all B cell lines. Thus, E-boxes display functional heterogeneity as transcriptional activators depending on host cell.
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PMID:'E-boxes' as promoter elements in B cell lines and untransformed B lymphocytes. 203 Nov 51

Monoclonal antibodies to rainbow trout (Oncorhynchus mykiss) IgM were prepared and characterized for use in immunoassays. Antibodies produced by the five clones reacted with the heavy chain of the immunoglobulin. No indication of different heavy chain isotype specificity was observed for the MAbs. One clone discerned IgM from rainbow trout while the other four clones cross-reacted with IgM from Atlantic salmon (Salmo salar) and from brown trout (Salmo trutta). The monoclonal antibodies identified a B-cell like lymphocyte population that contributed to approximately 45% of the blood leucocytes in rainbow trout but was absent in the thymus. The proportion of Ig+ cells was higher in blood lymphocyte cultures stimulated with lipopolysaccharide than in nonstimulated cultures or in cultures stimulated with Concanavalin A. Applied in an ELISA for measuring humoral antibodies to Vibrio anguillarum in trout, the monoclonal anti-rainbow trout IgM antibodies discriminated seropositive fish from control fish more efficiently than did polyclonal rabbit antitrout IgM antibodies.
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PMID:Monoclonal antibodies to salmonid immunoglobulin: characterization and applicability in immunoassays. 208 71

Peripheral blood B-lymphocyte markers and functions were observed in 21 patients with IgA nephropathy (IgA NP) and in 16 controls. IgA NP B lymphocytes expressed significantly higher positivity with Leu 1 (CD 5) monoclonal antibody than controls. CD 5 positive B lymphocytes are thought to be a distinct subset of the B cells (autoregulatory B lymphocytes) inducible in IgA NP by lipopolysaccharide (LPS) stimulation parallel to the higher expression of surface IgM heavy chain positivity. The activated state of IgA NP B lymphocytes has been proved by their higher OKIa (HLA-DR) positivities but lower IOB1a (CD 21, C3d-receptor) and decreased IgG-Fc-receptor (ox-rosette) expression. IgA NP B lymphocytes showed a higher IgA but also IgG and IgM polyclonal immunoglobulin production than control B lymphocytes in co-cultures with T lymphocytes. Not only regulatory T lymphocyte subsets but also serum derived from IgA NP patients stimulated the immunoglobulin production of IgA NP B cells.
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PMID:Peripheral B-lymphocyte markers and function in IgA nephropathy. 210 34

We have characterized the structure and expression of transcripts synthesized from the murine germline immunoglobulin gamma 3 heavy chain gene in certain B-lineage cells. The transcripts initiate upstream of the switch gamma 3 region, generating a 5' exon that is spliced to C gamma 3 exons. Expression of this germline transcript is induced when splenic B cells or A-MuLV-transformed pre-B cell lines are cultured in the presence of lipopolysaccharide (LPS). Addition of interleukin-4 (IL-4) to these lipopolysaccharide (LPS) cultures dramatically inhibits induction of the germline gamma 3 transcript. Induction of germline gamma 3 transcripts occurs before the increased accumulation of gamma 3-producing cells and VDJ-gamma 3 mRNA in cultures of splenic B cells. These data provide further evidence that germline CH transcriptional units are important components in the regulation of heavy chain class-switching. In addition, the pre-B cell lines that we describe represent the first example of permanent cell lines that regulate expression of the germline gamma locus in response to LPS plus IL-4 treatment in a manner analogous to normal B cells; therefore these lines should represent an excellent model system to further study the molecular mechanisms by which germline expression is regulated by these agents.
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PMID:Structure and expression of germline immunoglobulin gamma 3 heavy chain gene transcripts: implications for mitogen and lymphokine directed class-switching. 212 96

In this study, we analyzed the expression of genes encoding for components of the phagocyte superoxide anion-generating system in human phagocytes treated with interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS). Human neutrophils express high levels of the 47-kDa cytosolic factor (p47-phox), which are down-regulated after treatment with IFN-gamma, but not with LPS. On the contrary, the steady-state levels of the heavy chain subunit of cytochrome b558 (gp91-phox) were increased by IFN-gamma and LPS in human monocyte-derived macrophages and neutrophils in a time- and dose-dependent fashion, whereas cytochrome b558 light chain subunit (p22-phox) mRNA was not influenced by either agent. Studies on post-transcriptional regulation at the level of mRNA stability indicate that, in neutrophils, IFN-gamma has no influence on gp91-phox and p47-phox mRNA half-lives. The content of the two cytochrome b558 subunits was quantified by enzyme-linked immunosorbent assay, which revealed that, in neutrophils, gp91-phox levels doubled after 4 h of treatment with IFN-gamma or LPS. Monocyte/macrophage maturation was associated with a gradual decrease in gp91-phox mRNA and protein levels, which were both restored by treatment with IFN-gamma for 24-48 h. These results suggest that induction of the gp91-phox gene and protein product by IFN-gamma or LPS is an important requirement in the mechanism of the enhancement of neutrophil and macrophage oxidative metabolism.
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PMID:Molecular basis of interferon-gamma and lipopolysaccharide enhancement of phagocyte respiratory burst capability. Studies on the gene expression of several NADPH oxidase components. 217 1

Peripheral blood B-lymphocyte markers and functions were observed in 21 patients with IgA nephropathy (IgA NP), 18 patients with systemic lupus erythematosus (SLE) and 16 controls. IgA NP B-lymphocytes similarly to that of SLE B-lymphocytes expressed significantly higher positivity with Leu 1 (CD 5) monoclonal antibody than controls. CD 5 positive B-lymphocytes are thought to be a distinct subset of the B-cells (autoregulatory B-lymphocytes) inducible in IgA NP by lipopolysaccharide (LPS) stimulation in parallel to their expression of surface IgM heavy chain positivity. The activated state of IgA NP B-lymphocytes have been proved by their higher OKIa (HLA-DR) positivities but lower IOB1a (CD 21, C3b-receptor) and decreased IgG-Fc-receptor (ox- rosette) expression. IgA NP B-lymphocytes showed a higher IgA but also IgG and IgM polyclonal immunoglobulin production than control B-lymphocytes in co-cultures with T-lymphocytes. Not only regulatory T-lymphocyte subsets but also serum derived from IgA NP patients stimulated the immunoglobulin production of IgA NP B-lymphocytes.
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PMID:[Markers of peripheral B lymphocytes and their function in IgA nephropathy]. 220 18


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