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

Variation in the protein and lipopolysaccharide composition of the meningococcal outer membrane may be due to either serotype differences or to changes in cultural conditions. There are 12 antigenically distinct serotypes of group B meningococci, and these are associated with distinct major outer membrane protein patterns on sodium dodecyl sulfate-polyacrylamide gels. In most strains the predominant outer membrane protein carries the serotype-specific determinant. Certain strains, when grown under similar conditions in different media showed an altered membrane composition. The type 2 strain, M986, grown in modified Frantz medium-A, had a reduced amount of the major 41,000-dalton protein while a 28,000-dalton protein predominated. The altered protein composition may be related to changes in cell metabolism as reflected by the pH of the medium after growth. Growth of the organism in Frantz medium-B caused a negligible drop in pH and the 41,000-dalton protein remained predominant. There was also variation associated with changes in the growth rate. Increasing the aeration caused a concomitant increase in growth rate and cell yield. We observed two quantitative changes in outer membrane proteins in four of seven strains examined: (i) where only a single major protein changed (three strains), and (ii) where an increase in one protein component was associated with a decrease in another protein (one strain). When the strains were grown in tryptic soy broth (Difco Laboratories, Detroit, Mich.) with either high or low aeration, the total protein in the outer membrane remained constant. In contrast, with high aeration there was a significant increase in lipopolysaccharide. These studies suggest that the cell surface proteins may be altered by the organism to meet a variety of environmental conditions.
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PMID:Strain-specific variation in the protein and lipopolysaccharide composition of the group B meningococcal outer membrane. 6 Mar 32

In the course of the organic synthesis of model compounds similar in some features to the lipid moiety of endotoxic lipopolysaccharide (LPS), Nacylated-D-glucosamine derivatives were prepared. One of these, N-palmitoyl-D-glucosamine, has been previously found to be mitogenic for athymic nude mouse B cells. This and other N-acylated homologs were tested for adjuvant activity in the immune response to human gamma-globulin (HGG) and sheep red blood cells (SRBC) in mice. Comparable or superior enhancement of the immune response was obtained for these glycolipids when compared to LPS in assays measuring anti-SRBC or HGG hemagglutinin titers. In the determination of hemolytic plaque formation, considerable adjuvant effect was shown by the lauroyl derivative, and less but still significant enhancement was achieved by the N-palmitoyl-D-glucosamine. In the rosette formation assay, in addition to the above two glycolipids, N-oleyl-D-glucosamine showed good adjuvant effect. In the latter two assays, the LPS was a superior adjuvant as compared to the synthetic glycolipids. The radiation protective effect of some of the better synthetic adjuvants was also investigated in mice. It was found that although LPS was more effective in this assay, the N-myristoyl-D-glucosamine and N-decanoyl-D-glucosamine compounds gave a definite protection, since up to 40% of the lethally irradiated (700 R) mice survived.
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PMID:Synthetic glycolipid adjuvants. 6 Apr 50

In a previous report, it was shown that spleen cells from mice made tolerant to human gamma-globulin (HGG)5 could specifically inhibit the immune response of normal spleen cells after adoptive transfer to lethally irradiated recipients. However, that report also showed that the suppressive activity was only transiently associated with tolerant spleen cell populations. It was concluded from those experiments that while suppressive activity could be demonstrated in tolerant spleen cells under certain conditions, such activity was not obligatory for the maintainance of the tolerant state. The experiments presented here were performed to determine the nature of the effector cell(s) and the target cell(s) involved in this system of suppression of the immune response. Treatment of cells from tolerant animals with anti-thymocyte serum and complement to remove thymus-derived (T) cells completely abrogated suppresive activity. Removal of adherent cells from tolerant spleen cells by passage over glass wool columns resulted in partial loss of the suppression. The inhibitory activity of the suppressor cells was resistant to 900 R irradiation regardless of whether the tolerant spleen cells were irradiated before or after adoptive transfer. The cellular target(s) for the supprssor cells was examined by using lipopolysaccharide (LPS) as an alternative source of helper activity for the response to HGG. LPS, injected at the time of the initial antigenic challenge of mice that had been reconstituted with tolerant and normal spleen cells, prevented the expression of suppression against bone marrow-derived (B) cells. However, when LPS was presented only at the time of secondary antigenic challenge, it was unable to overcome suppression of the immune response of reconstituted recipients. Thus, LPS could produce a state where the B cells were resistant to suppression, but LPS could not rescue the responsiveness of B cells once the cells in the reconstituted recipient had been suppressed. In addition, the immune response to both the hapten dinitrophenol (DNP) and the carrier (HGG) were suppressed when recipients of tolerant and normal spleen cells were challenged with DNP6HGG. This indicates that T helper cells are also a target for suppression. The results presented in this paper are discussed in relation to a possible mechanism of suppression which proposes that suppressive activity represents the induction of tolerance in immunologically competent cells by HCG which is closely associated with the tolerant spleen cells.
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PMID:Specific, transient suppression of the immune response by HGG tolerant spleen cells. II. Effector cells and target cells. 6 92

The magnitude and heterogeneity of the immune response to dinitrophenylated bovine gamma globulin was measured in aged and young mice at a cellular level using an inhibition of plaque-forming cell assay. The primary and secondary responses of 24-mo-old mice were markedly depressed in magnitude and restricted in avidity for the DNP determinant when compared to 2-mo-old animals. Bacterial lipopolysaccharide given at the time of immunization increased the restriction in heterogeneity seen in 12- and 24-mo-old mice. Indirect PFCs were more severely depressed than direct PFCs in 24-mo-old mice. Syngeneic, lethally irradiated, 2-mo-old mice reconstituted with aged spleen cells exhibit the depressed and restricted response to DNP-BGG seen in old mice. When 10(8) young thymus cells were given together with old spleen cells the heterogeneity of the response was increased. When 2-mo- and 24-mo-old spleen cells were transferred together into young recipients the magnitude of the response to the young spleen cells markedly reduced. Thus, there appears to be a loss of thymic-helper cells and an increase in suppressor activity in aged animals.
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PMID:Immunological studies of aging. II. Loss of IgG and high avidity plaque-forming cells and increased suppressor cell activity in aging mice. 6 9

Among three analyzed serotypes of Shigella dysenteriae, namely, the serotypes 2,4 and 8, the serotype 2 proved to be a strong immunogen in rabbits, inducing anti-polysaccharide antibodies as well as antiprotein antibodies in all the animals. In contrast, the serotypes 4 and 8 were weak immunogens and among the rabbits some have synthesized only anti-proteins while others had antibodies against the somatic conjugate. Aside from the somatic antigens, large amounts of proteins were isolated from all the strains; however, the numerous determinants of these proteins were proven with the help of a serum to proteins from Sh. sonnei. The polysaccharides were specific for the serotype. The sensitivity of Sh. dysenteriae strains to phage P1 and the phage receptor actigity of different bacterial extracts were examined. By using the phage receptor neutralization test, it was possible to demonstrate that the receptor substance is a common component present in the lipopolysaccharide. The nature of neutralization has been discussed.
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PMID:Sh. dysenteriae serotypes2,4,8-immunochemistry and phage receptor activity. 6 97

Colistin methanesulfonate, a basic polypeptide similar to polymyxin E, has been shown to suppress the mitogenicity of lipopolysaccharide (LPS) from E. coli. It also inhibits the immunogenicity of a hapten-LPS conjugate. The inhibition was neither due to interference with the expression of hapten determinants, nor was it due to crossreactivity between the hapten and colistin methanesulfonate. As mitogenicity and immunogenicity was similarly affected, we conclude that activation of bursa-derived lymphocytes, in specific thymus-independent immune responses, does not take place in the absence of a mitogenic (non-Ig mediated) signal, thus supporting the hypothesis of the "one nonspecific signal" for B cell triggering.
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PMID:Inhibition of the mitogenicity of the carrier molecule results in loss of immunogenicity of a hapten-LPS conjugate. 6 27

Cell-mediated and humoral immune responses were assessed in mice at mid-term (day 10) in pregnancy. A significant but selective suppression of the primary in vivo antibody (plaque-forming cell) response to SRBC was observed, with the most pronounced effect being on the gammaA response. Similar results were obtained for secondary in vitro antibody synthesis by antigen-primed spleen cells from pregnant mice, demonstrating the intrinsic nature of the inhibition. Pregnant mouse serum (PMS) was shown to suppress primary in vitro antibody synthesis, and the inhibitory effect was abrogated by the selective removal of alpha-fetoprotein (AFP) using affinity chromatography. Normal mouse serum became similarly suppressive in vitro when purified AFP of fetal origin was added to it in concentrations approximating that found in PMS. Spleen cells from pregnant mice showed a suppressed mitogenic response to phytohemagglutinin, a lowered response to concanavalin. A, and a normal response to lipopolysaccharide. In contrast, the allogeneic response of these animals as measured in the one-way mixed lymphocyte culture was enhanced. PMS suppressed both allogeneic and mitogen-induced lymphocyte transformation by spleen cells from nonpregnant mice, and the effect was eliminated by the selective removal of AFP. These findings indicate an important functional role for AFP in normal embryological development.
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PMID:The immunosuppressive role of alpha-fetoprotein during pregnancy. 6 86

Bacterial lipopolysaccharide (LPS) induces interferons with different properties in mouse macrophages and B lymphocytes. Macrophage interferon is labile at 56 degrees C and is neutralized by anti-mouse fibroblast interferon at a dilution of 1:6,142. B cell interferon is more heat stable and is neutralized by the same antiserum only at a dilution of 1:276. Serum obtained early (1 h) after an intravenous injection of 100 mug of LPS resembled macrophage interferon, whereas serum obtained at later times resembled more and more B cell interferon. The diverse cellular origin of LPS-induced interferon may explain the broad hyporesponsiveness produced by LPS in animals.
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PMID:Cellular origin of interferon induced by bacterial lipopolysaccharide. 6 59

Mouse alpha-fetoprotein (AFP) suppressed the specific antibody response to the T-cell-dependent antigen sheep erythrocytes (SRBC) and the phytohemagglutinin- and concanavalin-A-stimulated DNA synthesis of purified T lymphocytes but failed to inhibit the T-cell-independent antibody response to dinitrophenyl-substituted Ficoll (DNP-Ficoll) and the lipopolysaccharide-stimulated polyclonal B-cell antibody synthesis. Mouse amniotic fluid (MAF) suppressed antibody responses to both T-cell-dependent and T-cell-independent antigens; however, the effects could be differentiated since dialysis of the MAF removed most of the suppressive effect on the DNP-Ficoll response but did not diminish the inhibitory action on the anti-SRBC response. The results indicate that AFP suppresses certain T-lymphocyte functions in vitro and does not act by directly inhibiting B-cell functions.
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PMID:The effects of mouse alpha-fetoprotein on T-cell-dependent and T-cell-independent immune responses in vitro. 6 7

Thymus of (C57Bl/6 x DBA/2) F1 mice was examined histologically, histochemically and ultrastructurally, seven days after intravenous injection of BCG, pertussis vaccine, lipopolysaccharide or human gamma globulin, or intraperitoneal injection of complete or incomplete Freund's adjuvants or of phytohemagglutinin. Only BCG induced a marked increase of the secretory activity of the thymic epithelium at all histological sites (cortex, corticomedullary junction and medullar). Only with this adjuvant was the epithelial hyperplasia associated with marked mitotic activity and high percentage of cells with cytoplasmic pyroninophilia among cortical lymphoid cells. The other substances tested produced different changes in the thymic epithelial cells according to the histologic zones. These results suggest that the epithelial cells of the cortex, the corticomedullary junction and the medulla respond differently to the agents tested and that the action of these substances upon thymus-dependent lymphoid cells may be indirect perhaps involving factors secreted by the epithelial cells.
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PMID:The effects of certain immunity systemic advuvants, PHA, and human gamma globulin on the thymic cortex of mice: a light and electron microscope study. 6 71


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