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

Culture supernatants of BW 5147 cells widely used for T-cell hybridization often manifest non-MHC-restricted, non-antigen-specific regulatory activities on the mixed lymphocyte reaction (MLR) of mouse cells. This report demonstrates that, whereas supernatants of BW 5147 cells grown at low concentrations (2 X 10(5)/ml) enhanced MLR, high cell concentration (2 X 10(6)/ml) supernatants markedly inhibited this reaction. BW 5147 cell-free extracts significantly inhibited MLR and in vitro antibody production (PFC), as well as the mitogenic response to lipopolysaccharide E. coli (LPS) of mouse spleen cells, but did not affect the response to an optimal dose of phytohaemagglutinin (PHA). Both supernatant and cell-free extract inhibitory activities were located in 60,000 MW fraction. Inhibitory material of low MW (less than 12,000) was also found in high cell concentration supernatants. A similar suppressive activity was exerted by cell-free extracts of P3 X 63 NS cells used for B-cell hybridization. The suppressive activity seemed to stem from some kind of interaction between BW 5147 cells and the fetal calf serum (FCS) of the culture medium. Supernatants from subclones of BW 5147 cells obtained in selected batches of FCS and maintained in the same serum, even at high cell concentrations, did not affect MLR, whereas the supernatants from the same subclones maintained in other batches definitely suppressed this reaction. Thus, provided that culture conditions are chosen carefully, subclones of BW 5147 devoid of effect on in vitro immune reactions can be obtained.
 ...
PMID:Selection of BW 5147 subclones devoid of non-specific suppressive activity for use in cell hybridization. 315 6

We have investigated the ability of both species of chlamydiae (C. trachomatis and C. psittaci), two major biovars of C. trachomatis (lymphogranuloma venereum and trachoma), and the two developmental forms of chlamydia (reticulate and elementary bodies) to stimulate murine spleen lymphocytes. All of these forms of the bacteria induce potent proliferation and differentiation to plaque-forming cells by B lymphocytes in vitro. Chlamydiae induce a broad antibody response, suggesting that stimulation is polyclonal in nature. Although all chlamydiae possess a lipopolysaccharide (LPS) genus-specific molecule similar to LPS found on Re mutant enterobacteria, polyclonal B cell stimulation is likely caused by molecules other than LPS, since i) polymyxin B failed to inhibit chlamydia-induced immunostimulation and ii) C3H/HeJ mice (LPS nonresponders) produced normal numbers of PFC after culture with chlamydia (but not LPS). Thus, a cross-species moiety that is not LPS is responsible for polyclonal stimulation by chlamydia. Because these bacteria can exist in latent forms in an animal, and all forms are immunostimulatory, the question of whether these bacteria can alter immune responses if released during other infections or immunizations has been raised.
 ...
PMID:Both species of chlamydia and two biovars of Chlamydia trachomatis stimulate mouse B lymphocytes. 351 67

These studies investigated the effects of exposure to chlordimeform (CDM), a formamidine pesticide, on selected in vivo immune parameters in the random bred CD-1 mouse. Further studies were done on the effects of this compound on the in vitro PFC response in C57BL/6 mice. Acute and 14-d exposure to CDM via the i.p. route resulted in a decrease in IgM antibody-forming (plaque-forming) cells (PFC) directed at the sheep red blood cell (sRBC) antigen when measured 4 d after i.p. immunization. This suppression was seen at doses as low as 20 mg/kg . d for 14 d. These same doses of CDM did not result in any alteration of cell-mediated immunity as measured by the delayed hypersensitivity response (DHR) to both keyhole limpet hemocyanin (KLH) and sRBC. Lymphocyte blastogenesis was increased in spleen cells from mice exposed to 40 mg/kg . d CDM in response to media alone, concanavalin A (Con A), and lipopolysaccharide (LPS). The in vitro PFC response by C57BL/6 mice was utilized to determine if CDM could suppress the antibody response due to a direct effect on the immune cells. CDM suppressed the in vitro PFC response only at concentrations that were directly cytolytic. A direct cytolytic effect was considered unlikely following exposure in the whole animal, since the suppression of the antibody response occurred in the absence of any effects on spleen cell number or spleen weight. To determine if route of exposure was a factor in the suppressive effects of CDM, 14-d studies were conducted administering CDM orally at doses up to 120 mg/kg . d. Both the CD-1 and C57BL/6 mouse were used to verify that a strain difference was not a factor. There was no effect on either the d 4 or d 5 antibody response, even though 43% of the mice exposed to 120 mg/kg died from the acute toxicity that can characterize this chemical. From an operational standpoint, these results indicate that the route of exposure of a compound relative to the route of administration of an antigen is an important consideration when determining the effects of that compound on an immune response. From an environmental standpoint, these results indicate that relatively high doses of chlordimeform do not result in consistent immunotoxicity as determined by the assays utilized.
 ...
PMID:Suppression of the antibody response by a formamidine pesticide: dependence on the route of exposure. 385 71

Lymphocytes activated by antigens or mitogens acquire the capacity to replicate viruses, and the number of activated lymphocytes can be estimated by the virus plaque assay. Concanavalin A and pokeweed mitogen produced 33-fold and 17-fold increases in virus plaqueforming cells (V-PFC), respectively, above background, while lipopolysaccharide produced only a 2- to 3-fold increase. T (thymus-derived lymphocyte)-depleted lymphocyte populations, derived from anti-theta-treated or nude (arthymic) mouse spleens, failed to produce V-PFC after culture with concanavalin A or pokeweed mitogen. The present studies thus demonstrate that the virus plaque assay measures activated T-lymphocytes.A dissociation between the V-PFC response and cell proliferation was previously observed in antigen-stimulated cells cultured in the presence of mitotic inhibitors. In the present studies, while stimulation of CBA (H2(k)) lymphocytes by DBA/2 (H2(d)) cells produced high levels of thymidine incorporation, lymphocyte target-cell cytotoxicity, and V-PFC, stimulation of BALB/c (H2(d)) lymphocytes against DBA/2 (H2(d)) cells resulted in even higher levels of thymidine incorporation with a virtual absence of cytotoxic lymphocytes or V-PFC. These results indicate that proliferation is not a sufficient condition for permitting lymphocytes either to exert cytotoxicity on target cells or to replicate viruses, and suggest that there may be a correlation between the development of V-PFC and cytotoxic lymphocytes. They are consistent with the view that there are at least two functional subpopulations of T-lymphocytes.
 ...
PMID:Enumeration of activated thymus-derived lymphocytes by the virus plaque assay. 436 71

Paraffin oil containing oil red O and emulsified with lipopolysaccharide obtained from Escherichia coli was ingested rapidly by guinea pig polymorphonuclear leukocytes or human peripheral blood granulocytes and monocytes after opsonization by fresh homologous serum. The initial rate of engulfment of the particles was spectrophotometrically assayed by determination of cell-associated oil red O and reflected the opsonic activity of the serum. This activity was resistant to dialysis but labile to heat, hydrazine, and zymosan, required divalent cations, and was maximal in the presence of Ca(++) and Mg(++). It was associated with the fixation of [(125)I]C3 to the lipopolysaccharide particles. Genetically C3-deficient serum had no opsonic activity, and this activity was restored by the addition of purified C3. Normal and C4-deficient guinea pig serum and normal, C2-, and C4-deficient human sera were equally effective in opsonizing lipopolysaccharide particles and lipopolysaccharide particles sensitized with heat-inactivated lipopolysaccharide immune serum. Cord serum deficient in glycine-rich beta-glycoprotein (GBG) (properdin factor B) had diminished opsonic activity which was improved by addition of purified GBG. Thus, C3 fixation to lipopolysaccharide particles occurs by means of the properdin system, and the opsonization and ingestion of lipopolysaccharide particles constitutes a quantitative functional assay of this pathway.
 ...
PMID:Serum-dependent phagocytosis of paraffin oil emulsified with bacterial lipopolysaccharide. 463 90

The number of PFC and of RFC was studied in mice which were unimmunized, immunized, or tolerant against lipopolysaccharide of E. coli 055:B5 origin. The number of PFC/10(6) spleen cells increased from 0.5 in normal to 209 in immunized mice. The corresponding figures for RFC were 93 and 513 RFC/10(6) spleen cells. In tolerant animals, which contained few or no PFC, the number of RFC was increased as compared to that found in unimmunized mice. The formation of rosettes was specific, since their formation was inhibited by soluble coli polysaccharide and by rabbit antisera against mouse immunoglobulins. The antigen-binding cells were not derived from thymus, neither in immune or tolerant mice, because they did not carry the theta antigen. It is suggested that the majority of antigen-binding cells present in tolerant animals are cells having receptors for the antigen of rather low affinity. The relevance of these findings for the induction of high and low zone tolerance is discussed.
 ...
PMID:Antigen-binding cells in mice immune or tolerant to Escherichia coli polysaccharide. 492 15

The reaction between endotoxic lipopolysaccharide (LPS) and the guinea pig complement system was shown to proceed by way of an intermediate complex, LPS-X, which contains at least six guinea pig serum proteins. LPS-X, like [unk] (sheep erythrocytes carrying antibody molecules and [unk] complexes), destroys the C3 molecule by cleavage. On incubation at 37 degrees C, LPS-X loses its capacity to destroy C3 at about the same rate as the decay of [unk], so that it has been assumed that LPS-X carries [unk] sites that are responsible for the destruction of C3. We have now shown that monospecific rabbit antiguinea pig C2, which effectively inhibits C3 cleavage by [unk], does not interfere with the destruction of C3 by LPS-X. Furthermore, not more than a trace of C2a(d) is released from LPS-X on incubation at 37 degrees C. These results indicate that LPS-X does not carry a significant quantity of [unk] and, hence, that its capacity to destroy C3 is due to another factor which is presumably a component of the properdin system.
 ...
PMID:An alternate complement pathway: C-3 cleaving activity, not due to C4,2a, on endotoxic lipopolysaccharide after treatment with guinea pig serum; relation to properdin. 528 85

The ability to clone hapten-specific B cells in agar and to subsequently trigger their clonal progeny to antibody synthesis was investigated. Fluorescein (FL) specific B cells were purified on FL-gelatin dishes and cultured in semisolid agar for 6 to 7 days; individual colonies were then picked for restimulation in microculture. FL-specific B cells could be cloned as efficiently as unpurified splenic B cells. The number of colonies formed depended on the presence of sheep erythrocytes (SRBC) or E. coli lipopolysaccharide (LPS) in the cultures. An additive number of colonies were observed with SRBC + LPS compared to that of SRBC or LPS alone. The colonies obtained from SRBC-containing cultures were stimulatable at high frequency by various FL-conjugated antigens to yield anti-FL PFC. However, colonies grown with LPS as the only additive were not stimulatable by any of the antigens tested. On the other hand, addition of M phi or SRBC as additional "mitogens" along with LPS in the agar resulted in progeny colonies that could respond in vitro. Although M phi did not increase the number of colonies, their presence enhanced the size and in some cases the frequency of stimulatable colonies. These data complement earlier observations in suggesting that different B cell subpopulations may grow under different cloning conditions. Moreover, the ability to stimulate the clonal progeny of single B cells to antibody synthesis should permit further definition of triggering and tolerance events at the single-cell level.
 ...
PMID:Hapten-specific murine colony-forming B cells: in vitro response of colonies to fluoresceinated thymus independent antigens. 616 21

Responses of B cells with or without receptors for C3 (CR) to polyclonal B cell activators (PBA) were studied. Mouse spleen cells were incubated with sheep red blood cells (SRBC) coated with antibody and complement to form rosettes, and they were separated by Ficoll-Hypaque density sedimentation into populations depleted of and enriched with lymphocytes bearing CR (CRL). These 2 populations were cultured with lipopolysaccharide (LPS), purified protein derivative of tuberculin (PPD), or dextran sulfate (DxS) and assayed for anti-TNP PFC. The CRL-depleted population responded well to LPS, poorly to PPD, and it showed practically no response to DxS, whereas the CRL-enriched population seemed to respond poorly to LPS but well to both PPD and DxS. The low responsiveness of the cRL-depleted population to PPD and DxS could not be explained by a shift of time-kinetics, by the dose-response profile of the responding cells, or by the depletion of adherent cells. Suppressor T cells did not take part in the reduced responses, since the treatment of the population with anti-Thy 1.2 plus complement could not restore the responses. These results indicate that B cells with CR [CR(+) B cells] respond well both to PPD and DxS, whereas the cells without CR [CR(-) B cells] respond poorly to PPD and DxS. It was difficult to evaluate the low responsiveness of CR(+) B cells to LPS because of the high background PFC of the cRL-enriched population.
 ...
PMID:Responses of B cells with or without C3 receptors to polyclonal B cell activators. 616 36

Recent studies have suggested that lipopolysaccharide (LPS) derived from gram-negative organisms such as Bacteroides, which are not members of the Enterobacteriaceae, stimulate B cells from the classic LPS-hyporesponsive C3H/HeJ mouse. In the present study, purified, phenol-water-extracted LPS from Bacteroides fragilis ATCC 25285 (B-LPS) was tested for its ability to induce in vivo and in vitro responses in classic LPS-responsive C3H/HeN, LPS-hyporesponsive C3H/HeJ, and (C3H/HeN X C3H/HeJ)F1 hybrid mice. B-LPS induced mitogenic responses in both C3H/HeN and C3H/HeJ spleen cell cultures when cells were cultured under standard conditions, i.e., 8 X 10(5) cells/well. Interestingly, when lower spleen cell numbers were tested with B-LPS, a typical responsive-nonresponsive pattern developed in which good mitogenic responses were induced by B-LPS in C3H/HeN cultures and in which low responses in C3H/HeJ spleen cell cultures were evident. In vivo immunization of mice with B-LPS resulted in high antibody responses in C3H/HeN, intermediate responses in F1, and low responses in C3H/HeJ mice. When purified splenic B cells were incubated with B-LPS, both mitogenic responses and polyclonal immunoglobulin M (IgM) synthesis occurred in C3H/HeN cultures, whereas intermediate responses were noted in F1 cultures and no response was seen in B cell cultures from C3H/HeJ mice. Furthermore, in vitro TNP-B-LPS responses were induced in C3H/HeN spleen cells or purified B cell cultures, and intermediate anti-TNP PFC responses occurred in F1 spleen cells or purified B cell cultures. The toxicity of B-LPS was tested in galactosamine-sensitized mice. The LD50 values for B-LPS in classic LPS-responsive C3H/HeN and C57BL/6J mice were 0.6 microgram and 1.1 microgram, respectively; F1 hybrid mice were approximately 15-fold more resistant, whereas C3H/HeJ mice gave an LD50 of 1650 micrograms. This study shows that phenol-water preparations of B-LPS are biologically active and induce responses in the classic LPS-responsive but not in the LPS-hyporesponsive C3H/HeJ mouse strain.
 ...
PMID:LPS regulation of the immune response: Bacteroides endotoxin induces mitogenic, polyclonal, and antibody responses in classical LPS responsive but not C3H/HeJ mice. 620 84


<< Previous 1 2 3 4 5 6 Next >>