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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Murine B cells were activated for 24 h with either lipopolysaccharide (LPS) or polyribosyl-ribitol-phosphate (PRP), followed by addition of interleukin 4 (IL-4) and the immunoglobulin isotypes secreted into the supernatant quantitated. Without IL-4, both LPS and PRP induced mainly IgM and IgG3 and no IgE secretion. Addition of IL-4 to both LPS- and PRP-activated cells decreased the IgM and IgG3 secretion and induced a large IgG1 production. In contrast to IgG1, only LPS-activated cells secreted large amounts of IgE, demonstrating that the nature of the polyclonal B cell activator also plays an important role in the IL-4 induced IgE formation. The effect of LPS and IL-4 on high- and low-density sIgM+/sIgD+ cells was also investigated. LPS and IL-4 induced IgG1 and IgE secretion by both populations. Low-density B cells from mice infected with the parasite Nippostrongylus brasiliensis formed more IgE than low-density B cells from normal mice, presumably because these mice have more in vivo preactivated B cells committed to IgE formation. The data show that IL-4 can act on both small high-density resting B cells as well as on in vivo preactivated low-density B cells to induce IgG1 and IgE secretion.
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PMID:Interleukin 4 acts on both high- and low-density murine B cell subpopulations to induce IgE and IgG1 synthesis in vitro. 278 84

Mouse interleukin 4 (IL-4) has been shown to act on B cells as an induction factor for Ig class switch. We studied the characteristics of IL-4-regulated Ig isotype production in lipopolysaccharide (LPS)-stimulated splenic B-cell cultures with emphasis on the comparison between the IgG1 and IgE responses. The results show that the kinetics for the appearance of IgG1 and IgE isotypes are similar, but that the dose of IL-4 required for the induction of an IgE response is 3-10 times higher than that for an IgG1 response. No requirement for T cells was found for the induction of either isotype. Pre-incubation of cells for 24 h with IL-4 alone was sufficient to induce an IgG1 response when cells were recultured with LPS from days 1 to 6. However, the simultaneous presence of both IL-4 and LPS for at least 24 h was required for a detectable IgE response. For an optimal IgE response, IL-4 needed to be present for more than 72 h in LPS-activated cultures. The possible reasons for the different regulation of IgG1 and IgE responses are discussed.
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PMID:Regulation of IgG1 and IgE synthesis by interleukin 4 in mouse B cells. 278 29

The addition of concanavalin A-stimulated supernatants of the helper T cell clone, D9.1, to cultures of lipopolysaccharide (LPS)-stimulated T-depleted mouse spleen cells caused more than a 100-fold increase in immunoglobulin (Ig) E production. These supernatants cause a 10-fold to 15-fold increase in IgG1, a fivefold to 10-fold increase in IgA, and a fivefold to 10-fold decrease in IgG3. These effects are optimal when the supernatants are added 1 to 2 days after stimulation with LPS. Cells from mouse strains that normally give little or no IgE response in vivo give normal IgE levels in response to LPS plus the supernatant of Concanavalin A-stimulated D9.1 cells in vitro. The enhancement of both IgE and IgG1 can be completely inhibited by relatively low concentrations of interferon-gamma (IFN-gamma). Both the IgE-enhancing activity and IFN-gamma act directly upon purified B cells.
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PMID:A T cell activity that enhances polyclonal IgE production and its inhibition by interferon-gamma. 293 82

Supernatants from a subset of helper T cell clones can enhance IgA, IgE, and IgG1 production in cultures of lipopolysaccharide-stimulated, T cell-depleted spleen cells. The lymphokine interleukin (IL)-4 has been shown to cause the IgE and IgG1 enhancement produced by these supernatants. IgA enhancement, however, is mediated by a factor distinct from IL-4, although IL-4 can potentiate the effect of the IgA-enhancing factor. IgA-enhancing factor is also distinct from IL-1, IL-2, IL-3, granulocyte-macrophage colony-stimulating factor, and interferon-gamma and acts directly on B cells. Purified IgA-enhancing factor enhances IgA production three- to sixfold yet causes less than a twofold increase in other isotypes. The IgA enhancing activity is not inhibited by concentrations of interferon-gamma that inhibit IL-4 activities. In the accompanying article, we show that this IgA enhancing activity is a novel property of the lymphokine IL-5.
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PMID:A mouse T cell product that preferentially enhances IgA production. I. Biologic characterization. 296 Jul 39

Certain subsets of helper T cells, following stimulation with concanavalin A, secrete factors that specifically enhance the production of IgG1, IgE, and IgA by lipopolysaccharide-stimulated B cells. In the previous report, we describe a factor from the helper T cell line MB2-1 which enhances IgA production. IgA-enhancing factor has been purified from serum-free supernatants of this cell line. The purified lymphokine is a family of microheterogeneous polypeptides presumably modified post-translationally. IgA-enhancing factor has a native m.w. of 45,000 to 60,000 with subunits of between 24,000 and 28,000 under reducing conditions. Upon Edman degradation, a single amino-terminal sequence is detected which is identical to that of the lymphokine interleukin 5. IgA-enhancing factor activity is thus mediated by the same polypeptide that has been characterized as type II B cell growth factor, T cell-replacing factor, and eosinophil-differentiation factor.
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PMID:A mouse T cell product that preferentially enhances IgA production. II. Physicochemical characterization. 296 Jul 40

IgM+ cells cultured from the I.29 B cell lymphoma can be induced with lipopolysaccharide (LPS) or, to a greater extent, with LPS plus anti-idiotype antibody to switch to IgG2a, IgE or IgA expression. The isotype switch is accompanied by rearrangement of immunoglobulin (Ig) heavy (H) chain genes. Here we demonstrate that the commitment of the I.29 IgM+ cells to switch to IgA appears to be manifested by hypomethylation of the alpha constant region genes in IgM+ cells, and by the presence of small amounts of RNAs transcribed from non-rearranged alpha gene(s) in IgM+ cells. The commitment to switch to IgE or IgG2a is also in accord with the presence of small amounts of RNA transcripts from the non-rearranged epsilon and gamma 2a genes, although the hypomethylation of the epsilon and gamma 2a genes is not as dramatic as that of the alpha genes. These results suggest that I.29 cells switch specifically to IgA, IgE or IgG2a due to the activation of the corresponding H chain constant region genes in IgM+ cells prior to the actual switch recombination event.
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PMID:Specificity of immunoglobulin heavy chain switch correlates with activity of germline heavy chain genes prior to switching. 300 21

B-cell stimulatory factor-1 (BSF-1) is a T-cell product of relative molecular mass 20,000 (Mr, 20K) initially described as a cofactor required for DNA synthesis by resting mouse B cells stimulated with low concentrations of anti-IgM antibodies. It acts on resting B cells to enhance the expression of class II major histocompatibility complex (MHC) molecules, to prepare these cells to respond more promptly to subsequent stimuli, such as anti-IgM antibodies, and causes the secretion of IgG1 and IgE by B cells stimulated with lipopolysaccharide (LPS). BSF-1 has been shown to stimulate T cell lines, resting T cells and some mast cell lines. Recently, the designation interleukin-4 (IL-4) has been suggested for BSF-1. We report here the existence of high-affinity cell-surface receptors specific for BSF-1 on both B and T lymphocytes, and on cells of several other haematopoietic lineages, including mast cell, macrophage and undifferentiated haematopoietic cell lines. Resting B and T lymphocytes express receptors, which increase in number upon activation of B cells with LPS or anti-IgM, and of T cells with concanavalin A. Cross-linking of 125I-labelled-BSF-1 to its receptors creates a complex of Mr approximately 80,000.
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PMID:Receptors for B-cell stimulatory factor-1 expressed on cells of haematopoietic lineage. 310 Sep 61

Cells from the monoclonal B cell lymphoma I.29 expressing surface IgM (mu +) are capable of differentiating in vitro to IgM secretion and of switching to IgA or IgE production in response to lipopolysaccharide (LPS) stimulation. To determine whether a single mu + B cell is capable of undertaking both differentiative pathways (isotype switch and plasma cell differentiation) I.29 mu + cells were cloned by limiting dilution and a panel of clones were analyzed by immunofluorescence, endogenous labeling and Northern blotting. While 100% of the clones could differentiate toward IgM secretion, only a proportion of them (greater than 70%) also switched to IgA and/or IgE production. Certain clones switched preferentially to a specific isotype. Taken together with the observation that C gamma genes were never the target of switching in our experiments, these data suggest that individual mu + clones from the I.29 lymphoma are "precommitted" as for their switching potentials. The subclones that showed a high frequency of switching to IgA transcribed the germ line C alpha gene(s), suggesting a role for chromatin structure in determining the isotype switch specificity. Switch variant clones expressing either IgA or IgE on the cell surface were isolated and found capable of further differentiating toward Ig secretion in response to LPS. On the contrary, we could not induce switch to IgA in IgE-producing cells. Unlike mu + and alpha + cells, all the switch variant clones expressing IgE tested by endogenous labeling constitutively secreted large amounts of IgE in the supernatants even in the absence of LPS stimulation.
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PMID:Differentiation in the murine B cell lymphoma I.29: individual mu + clones may be induced by lipopolysaccharide to both IgM secretion and isotype switching. 310 70

Serum antibodies to the contents of cuprophan hollow-fiber dialyzers were demonstrated by immunodiffusion in 36 of 68 hemodialysis patients. The antibodies were not absorbed by ethylene oxide or washed cuprophan hollow fibers. No cross-reactivity with Escherichia coli lipopolysaccharide and pneumococcal polysaccharides was noted. The antibodies were IgM and probably IgG. Washed cuprophan hollow fibers did not absorb IgE detected by radioallergosorbent test (RAST). Lymphocyte transformation to the contents of both cuprophan hollow fiber and polyacrylonitrile plate dialyzers was demonstrated. Materials added in manufacture of dialyzers are immunogenic. The long-term biologic effects are unknown.
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PMID:Immune responses to dialyzer contents by dialysis patients. 312 94

The synovial fluid of patients with rheumatoid arthritis (RA) contains a biologically active factor which has the ability to replace T cells for the induction of antibody secretion by human blood lymphoid cells stimulated by pokeweed mitogen (PWM) in vitro. This factor, which will be referred to as RA-SF (synovial fluid), also has the capacity to act as a B cell-stimulatory factor of mouse splenic lymphocytes in the presence of lipopolysaccharide (LPS). Using a test system developed for the definition of interleukin 4 (IL-4), which is a B cell-stimulating lymphokine which preferentially activates the synthesis of selected Ig classes in mouse lymphoid cells, we have shown that RA-SF has properties similar to IL-4 in that it induces differentiation of antibody secretion in the LPS-pretreated mouse cell, but unlike IL-4, which gives IgG1 and IgE, it selectively induces IgG2b synthesis. The present study demonstrates that RA-SF has a biological activity that is reminiscent of other B cell-stimulating mouse lymphokines, but it is biologically distinct from IL-2, IL-4, and IL-5. Recent data also indicate that it is distinct from gamma interferon (IFN-gamma). Therefore, we conclude that the biological activity of RA-SF has properties in common with a T-cell replacing (TRF) and B-cell differentiation factor (BCDF) and probably represents yet another biological activity which so far lacks an experimental counterpart. The relevance of this factor for autoantibody synthesis is discussed.
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PMID:Biological characterization of T cell-replacing factor in the synovial fluid of rheumatoid arthritis patients. 326 Jun 84


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