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

The nature of the protective substance in ribosomal ribonucleic acid and protein extracts of Salmonella has been investigated. The results of experiments in which vaccines were prepared from isogenic strains and strains with defects in lipopolysaccharide synthesis show that O antigens contaminate both ribonucleic acid and protein ribosomal extracts, and are responsible for at least part of their strain-specific protective activity. In addition, it was observed that a ribosomal ribonucleic acid preparation from S. adelaide contains a heat-stable immunogen which is not an O antigen or that gives cross-protection across species lines. The contribution of ribosomes to the immunity induced by "ribosomal vaccines" is discussed.
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PMID:Evidence for O antigens as the antigenic determinants in "ribosomal" vaccines prepared from Salmonella. 5 Oct 7

The paper describes cultivations of 4 Salmonella S-forms and 1 SR mutant, performed in complex medium under constant conditions of temperature, pH and aeration. The experiments show that lipopolysaccharide (LPS) biosynthesis underlies quantitative differences with the growth phases, resulting in changes in the LPS content of the cell masses. During the exponential phase a decline takes place in the percentage of LPS contained by the 4 S-forms. In addition, in the phase of delayed growth acceleration, 3 of these strains exhibit temporary, complete stagnation in LPS formation. When the cultures enter the stationary phase, LPS biosynthesis also discontinues. The SR-mutant differs from the S-forms especially in that the rate of LPS synthesis and with it, the percent lipopolysaccharide content of the cells, increase greatly in the exponential growth phase. The causes and effects of the changes observed are discussed.
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PMID:[Growth and lipopolysaccharide content of salmonellae grown in submersed cultures according to the batch-method. 2. Communication: influence of growth phases on lipopolysaccharide synthesis (author's transl)]. 5 51

In the present study in mice we used the Jerne plaque assay to compare the immunity enhancing potential of different Gram-negative bacteria with special regard to their endotoxin. The results confirm the recent finding that injection of Escherichia coli bacteria of various serotypes may enhance the IgG antibody response to the O antigen of a serologically unrelated E. coli strain injected subsequently, but may suppress the IgM antibody formation. The O antibodies formed were of low avidity but were antigen specific. Smaller amounts of antibodies were formed to a serologically unrelated antigen, E. coli O76, which had not been injected. Of the strains tested as primary stimuli E. coli O4 gave considerably greater enhancement than any other serotype including the homologous E. coli O6, when a short interval between the injections was used. The influence of O4 on the serologically unrelated anti-O6 response was stronger than on the response to the cross-reactive E. coli O18 antigen, suggesting that O antigen cross-reactivity is not the basis for the immunomodulation. Formalin-killed bacteria were more effective in this respect than boiled bacteria or purified lipopolysaccharide and rough mutants (E. coli R1--R4) and E. coli O4 were less effective than many of the other smooth E. coli. These findings suggest that shared determinants in the lipid, basic carbohydrate core or Kunin common antigen portions of the endotoxin do not play the major immunomodulating role in this system. Salmonella reading but not Pseudomonas aeruginosa affected the anti-E. coli O6 response in a similar manner. One explanation for the alterations in the immune response observed implies the presence of an antigen determinant shared by many Enterobacteriaceae in such a position in relation to the O antigen that it can be utilized for cellular co-operative events in the O antibody response. The protein portion of the endotoxin protein--lipid--carbohydrate complex is a possible location.
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PMID:Alteration of the antibody response to Escherichia coli O antigen in mice by prior exposure to various somatic antigens. 5 29

Mixtures of isogenic thymocytes (TC) and lymph node cells (LNC) were shown to exhibit synergistic responsiveness to M and H-2 alloantigens in the mixed lymphocyte interaction (MLI). With respect to the kinetics and magnitude of proliferation and effector cell generation, the response occurring in synergizing cultures closely resembled that of optimal numbers of LNC or spleen cells (SC). In addition, the antigen specificity of effector cells generated by synergizing cultures was similar to that of effectors derived from cultures containing optimal numbers of responding SC. LNC-TC mixtures also exhibited synergy in response to the phytomitogens concanavalin A and pokeweed mitogen but not to phytohemagglutinin. Weakly positive synergy was observed in response to bacterial lipopolysaccharide. It is proposed that the phenomenon of synergy is not restricted to cultures containing mixtures of LNC and TC but also occurs in cultures containing optimal numbers of LNC or SC as a result of interactions between subpopulations of lymphocytes contained within these tissues.
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PMID:Lymphoid cell subpopulations. I. Synergy between lymph node cells and thymocytes in response to alloantigens and mitogens. 5 85

We have shown previously that in the differentiation of fetal liver cells to mature B cells in irradiated hosts, these cells sequentially gain responsiveness to the polyclonal B-cell activators dextran-sulphate (DxS), lipopolysaccharide (LPS), and purified protein derivative from tuberculin (PPD), in that order. In this paper we show that both fetal liver cells and adult bone marrow cells responded with proliferation to DxS, but not to LPS OR PPD. However, neither fetal liver nor bone marrow cells gave rise to detectable numbers of high-rate antibody-secreting cells on short-term stimulation by polyclonal B-cell activators. The lack of LPS and and PPD responses of fetal liver and bone marrow cells could not be ascribed to the presence of inhibitory cells, and the DxS-induced response in these cell populations was not dependent on adherent cells. However, LPS could inhibit the DxS response of fetal liver cells, possibly indicating that DxS-responsive cells are precursors to B cells. Direct evidence was provided that DxS activated B-cell precursors in bone marrow. Thus, this cell population became responsive to LPS after DxS prestimulation, as measured by DNA synthesis. Bone marrow cells, sequentially stimulated with DxS and LPS, contained increased numbers of cells with surface immunoglobulin, although no significant increase in numbers of antibody-secreting cells was obtained. These data indicate that DxS had the capacity to increase the rate of differentiation of B-cell precursors. Finally, we show that the sequential appearance of responsiveness in B-cell differentiation to polyclonal B-cell activators is not due to lack of accessory cells during early stages in maturation.
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PMID:Responsiveness of lymphoid precursors to polyclonal B-cell activators. 5 77

We have studied the effects of lipopolysaccharide (LPS) on the primary in vivo immune response to the hapten (4-hydroxy-3,5-dinitrophenyl)acetyl (NNP), with special reference to the avidity and affinity of the early appearing 19S and 7S antibodies. Comparisons were made of the immune response to NNP in groups of mice given either antigen alone, LPS alone, or antigen plus LPS. The avidity of antibodies induced by LPS plus antigen were similar to that found after injection of antigen alone, in spite of the fact that the antibodies were more numerous. However, when comparing the avidity of antibodies produced in animals given only LPS with those given LPS plus antigen, the latter group was often found to have fewer low-avidity 19S-antibody-producing cells. The affinity of 7S antibodies was also similar in the two groups given antigen or antigen plus LPS. Kinetic studies of the effect of LPS on the primary immune response to NNP showed that synergy was observed only before or after the peak response in groups given antigen alone. It is concluded that LPS under synergy conditions acts preferentially on specific antigen-sensitive cells, which are distinct from those that are activated to polyclonal antibody synthesis by LPS alone. Possible mechanisms for the adjuvant effect of LPS are discussed.
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PMID:The effect of lipopolysaccharide on the primary immune response to the hapten NNP. 5 84

One thymus-independent immunogen, trinitrophenylated lipopolysaccharide (TNP-LPS) has been studied in vivo and in vitro in C3H/He and C3H/HeJ strains of mice. C3H/HeJ mice have been shown to be low responders, and C3H/He mice high responders to this immunogen. This 'low responder' status of C3H/HeJ mice has been demonstrated to be consequent to an intrinsic defect present at least at the level of B cells. It was demonstrated that high responder cells or 'in vivo milieu' could not restore this deficit to C3H/HeJ cells. It is proposed that the adjuvanticity, mitogenicity and polyclonal activating capacity of LPS are all fundamental to its property of acting as a thymus-independent carrier for the TNP determinant. This observation is discussed from the point of view that the T-cell independence for an antigen cannot derive solely from its multivalency but must depend upon the intrinsic adjuvanticity of that molecule.
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PMID:The 'intrinsic adjuvanticity' and immunogenicity of trinitrophenylated lipopolysaccharide. 5 94

Determinants controlled by the I region of the murine H-2 complex provoked the generation of cytotoxic T lymphocytes (CTL) in both a secondary and primary mixed lymphocyte culture. The stimulating determinants appeared to be controlled by loci within the I-A subregion. The target antigens of the CTL generated were present on both lipopolysaccharide- and concanavalin-induced blast lymphocytes, but were barely detectable on phytohemagglutinin-induced blast cells. The stimulating capacity for CTL induction of a complete H-2 complex incompatibility by far exceeded the sum of H-2D/K-region and I-region incompatibility, respectively.
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PMID:Induction of cytotoxic T lymphocytes against I-region-coded determinants: in vitro evidence for a third histocompatibility locus in the mouse. 5 65

2-Amino-2-deoxygalacturonic acid was identified as a component of the lipopolysaccharide from Pseudomonas aeruginosa N.C.T.C. 8505. The compound probably occurs in the region of polysaccharide responsible for O-antigenic specificity.
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PMID:2-Amino-2-deoxygalacturonic acid in lipopolysaccharides from Pseudomonas aerugimosa. 5 64

Earlier studies, which indicated that high titers of O-specific antibody to the patient's infecting organism in acute-phase serum specimens were not associated with a decrease in the frequency of subsequent shock and death in bacteremia due to gram-negative bacilli, were reexamined for evaluation of the protective activity of specific IgG and IgM antibody. Titers of hemagglutination antibody and levels of IgM, determined by indirect immunofluorescent staining of the patient's infecting organism, as well as hemagglutination titers after reduction of serum with 2-mercaptoethanol and IgG levels, correlated closely (P less than 0.001). High titers of IgG antibody to the patient's infecting organism in acute-phase specimens were associated with a significant reduction in the frequency of shock and death in bacteremia. In contrast, high titers of IgG antibody were not associated with a diminution in the frequency of shock and death. The previously demonstrated protective activity of antibody to an antigen, Re lipopolysaccharide, shared by most gram-negative bacilli was reconfirmed and shown to be independent of the protective activity of O-specific IgG antibody.
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PMID:Effects of IgM and IgG antibody in patients with bacteremia due to gram-negative bacilli. 5 97


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