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)

In the course of investigating the mechanisms of the in vitro immunosuppressive effect of D-penicillamine in the presence of copper ion with murine spleen cells, we observed that copper ion, by itself, exhibited a strong immunosuppressive effect at a low concentration. Namely, the addition of CuSO4 at a concentration of 0.1 to 2 microM markedly inhibited the development of SRBC-specific plaque forming cells (PFC) without causing cytotoxicity. CuSO4, at the same concentration range, suppressed the lipopolysaccharide (LPS)-induced proliferative response, but not the response induced by concanavalin A (Con A). The suppressive effect of CuSO4 on the antibody production was reversed by 500 U/ml of catalase, but that on the LPS-induced proliferative response was not. CuSO4 also substantially suppressed the pokeweed mitogen-induced proliferative response. These findings suggest that CuSO4 acts as an inhibitor of B cell proliferation and, through this effect, markedly inhibits the antibody production in murine spleen cells.
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PMID:CuSO4 as an inhibitor of B cell proliferation. 208 7

Several immunological functions of B and T cells including IL-2 receptor expression on T cells were measured in 12-month-old Fisher-344 male rats maintained from 6 weeks of age on an ad libitum (AL) or a 40% food-restricted (FR) diet. Direct anti-SRBC plaque-forming cell (PFC) assays revealed a higher response in FR rats than in AL rats when splenocytes were cultured with or without recombinant interleukin-2 (rIL-2). B cell functions were studied by using nylon wool-purified splenic B cells stimulated either with rIL-2, lipopolysaccharide (LPS), or Salmonella typhimurium mitogen (STM) as a thymus-independent antigen. Reserve plaque assay showed no difference between FR and AL rats in the secretion of anti-IgM and anti-IgG antibodies. In addition, no difference was found in proliferation of B cells stimulated by LPS, STM mitogens or rIL-2. Although purified splenic T cells demonstrated an equally proliferative response in FR and AL rats when cultured with concanavalin A (Con A) or phytohemagglutinin (PHA), T cells in FR rats developed higher responses when stimulated with an alloantigen and rIL-2. Time-course studies carried out to measure high-affinity (HA) IL-2 receptor (R) molecules by using purified T cells with rIL-2 and 125I-labeled IL-2 revealed a higher expression of IL-2R molecules on T cells of FR rats than on T cells of AL rats at 72 h after culturing with Con A.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunological functions in food-restricted rats: enhanced expression of high-affinity interleukin-2 receptors on splenic T cells. 253 90

We described a cloned dendritic cell, clone Den-1, that is a potent accessory cell for some B cell responses. Clone Den-1 produces a novel lymphokine that is distinct from previously described factors produced by T cells. In the present study, we compare the role of nonspecific helper factors produced by Den-1 (Den-1 SN) or the T cell thymoma EL4 (EL4-SN) in promotion of B cell plaque-forming cell (PFC) responses to a variety of antigens. We find that the antigen in culture determines the B cell requirement for dendritic and/or T cell factors. B cell PFC responses to TNP-Brucella abortus (BA) and TNP-lipopolysaccharide (LPS) are greatly increased by EL4-SN but show little, if any, enhancement with Den-1 SN. Responses to TNP-polyacrylamide are reconstituted by either Den-1 SN or EL4-SN, whereas responses to TNP-Ficoll, TNP-dextran and TNP-levan are reconstituted by Den-1 SN and are much less sensitive to factors present in EL4-SN. Responses to SRBC require the presence of both Den-1 SN and EL4-SN. We also show that the time at which Den-1 SN must be provided to the B cell is dependent on the antigen in culture. Our findings are discussed in terms of present classification of antigens based on their ability to stimulate various B cell subpopulations.
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PMID:B cell activation: role of dendritic and T cell factors in the response to thymic-independent and -dependent antigens. 258 2

Leptospiral lipopolysaccharide can enhance the nonspecific resistance of host to infection. By researching its mechanism, we found: (1) The phagocytic function of peritoneal macrophages of guinea pigs was strengthened by E-LPS and L-LPS; (2) L-LPS and E-LPS activated peritoneal macrophages of mice then enlarging the cell raji, and increase the quantity and activity of intracellular acid phosphatase. Relatively, the L-LPS might have a greater action in synthesis of the enzyme, while the E-LPS mainly enhanced the activity of the enzyme; (3) L-LPS and E-LPS appeared to be immunomodulant. When they were injected 3d after immunizing the mice with SRBC, immune adjuvant effect developed; however, if the injection of LPS was made 24h prior to the immunization, it would result in immunosuppression.
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PMID:[Studies on enhancement of nonspecific resistance to infection by leptospiral lipopolysaccharide. II. The mechanisms of the nonspecific protective activity of the LPS]. 258 63

Biological activities of lipopolysaccharide-like (LPS-like, phenol/water extract) and endotoxin-like (butanol/water extract) preparations from Trepomena hyodysenteriae were examined. The treponemal phenol/water and butanol/water extracts were less toxic than E. coli LPS for murine peritoneal exudate cells (PECs). The treponemal phenol/water extract did not stimulate the production of interleukin-1 (IL-1) or tumor necrosis factor (TNF) from murine PECs. The treponemal butanol/water extract did induce production of IL-1 and TNF but at doses 5- to 50-fold higher than E. coli LPS. Natural killer cell activity was augmented by the treponemal butanol/water extract but not by the phenol/water extract. Suppression of a splenic anti-SRBC plaque forming cell response was observed when the LPS-like and endotoxin-like preparations from T. hyodysenteriae were administered 24 h prior to injection of the SRBC. These findings indicate that the butanol/water extracted material from T. hyodysenteriae is more biologically active than the phenol/water extracted material and that the treponemal endotoxin may contribute to the inflammatory response of swine dysentery by inducing IL-1 and TNF production.
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PMID:Pathogenesis of Treponema hyodysenteriae: induction of interleukin-1 and tumor necrosis factor by a treponemal butanol/water extract (endotoxin). 262 26

The effects of eicosapentaenoic acid (EPA) on the humoral immune response in fat free diet-fed (FF) mice were studied. The lowered anti-SRBC PFC activity of ICR male FF mice was restored in a dose-dependent manner when EPA was administered orally at doses of 60-360 mg/kg/day for 20 days. In in vitro experiments, EPA similarly enhanced anti-SRBC PFC activity but did not affect the response against lipopolysaccharide. Furthermore, EPA did not cause any substantial effect on T suppressor cell activity induced by Concanavalin A in vitro. On the other hand, T helper cell activity induced by keyhole limpet hemocyanin was augmented. From these results, it is suggestive that EPA caused immunopotentiation to FF mice at least partially by an enhancement of T helper cell activities.
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PMID:Ethyl eicosapentaenoate restored the immunosuppression in mice fed fat-free diet. 284 87

The spontaneous in vitro anti-DNA antibody response generated by preautoimmune and many normal mouse spleen cells was suppressed by the addition of syngeneic thymocytes or splenic T cells. Suppressive activity was found in normal mice (DBA/2J) and to an equivalent degree in the autoimmune (New Zealand Black X New Zealand White)F1 (B/W) strain. The suppressor cells were cortisone-resistant, radiosensitive and carried Lyt 1 and Lyt 2 markers. Nonspecific suppression was not involved since the primary and primed in vitro anti-sheep erythrocyte (anti-SRBC) responses were unaffected. Both spontaneous and lipopolysaccharide-stimulated anti-DNA antibody responses could be suppressed. There was no difference in the suppressive activity of cells from young or old, normal or autoimmune mice. These T cells may therefore play a role in preventing the anti-DNA antibody response in normal and young B/W mice, but evidently fail to influence the development of in vivo anti-DNA autoimmune responses in the old B/W mice.
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PMID:Regulation of an in vitro anti-DNA antibody response by thymocytes and T cells from NZB/W and normal mice. 286 Sep 75

Previously, we have demonstrated that supernatants from autologous mixed lymphocyte (AMLR) cultures contain helper factors which can mediate the development of a cytotoxic T-cell response to hapten modified self. In the current study, the effect of AMLR supernatants on the humoral response was explored. BALB/C splenic non-T cells produced a large polyclonal antibody response to lipopolysaccharide (LPS), as measured in a Protein A SRBC plaque assay. Surprisingly, syngeneic AMLR supernatants suppressed the LPS-induced generation of plaque-forming cells. The presence of T cells in the stimulated cultures did not affect suppressor activity. The decreased response was not the result of a shift in kinetics, as maximal activity was observed on Day 4, whether or not AMLR supernatants were added. The AMLR culture supernatants were most effective in suppressing the plaque-forming cell response when added at the initiation of culture. AMLR supernatants added after 24 hr of culture resulted in only about 50% of maximum suppression. Supernatants added at 48 or 72 hr had no effect. Interferon-gamma (IFN-gamma) has been detected in AMLR culture supernatant and has been reported to suppress the development of plaque-forming cells in response to LPS. However, it is unlikely the suppressive activity observed in these studies is due to IFN-gamma. Dialysis of the AMLR culture supernatant against a pH 2 buffer for 24 hr or incubation at 70, 80, or 90 degrees C for 10 min, treatments that inactivate IFN-gamma, enhanced suppression. These results suggest that in addition to cytotoxic-T-cell helper factors, the cellular interactions in the AMLR induces the production of a stable mediator(s) which is able to directly suppress B cells at an early stage of their development into plasma cells.
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PMID:Suppression of a polyclonal B-cell response by supernatants from the murine autologous mixed lymphocyte reaction. 294 Nov 57

The potential role of donor's mature T lymphocytes on the recovery of various immunological functions and hematopoiesis was investigated in lethally irradiated BALB/c mice by studying reconstitution with normal, as compared with T-cell-depleted, syngeneic marrow grafts. Recovery of total, as well as mononuclear, peripheral white blood cell counts, platelets, hemoglobin levels, proportion of Thy 1.2+ cells, responses to concanavalin A, phytohemagglutinin and lipopolysaccharide, mixed lymphocyte response, cell-mediated lympholysis response, anti-SRBC agglutinins and natural killer activity were basically similar in recipients of unmanipulated (as compared with T cell depleted) syngeneic marrow grafts. The data suggest that in a syngeneic murine bone marrow transplantation setting, mature donor T lymphocytes do not seem to play a major role in immunohemopoiesis. Normal T cell number and T-cell-dependent immune function can be readily regenerated out of the stem cell reservoir of adult donors following transplantation into lethally ablated recipients.
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PMID:Bone marrow transplantation with T-cell-depleted grafts. I. Reconstitution of immunohemopoietic functions in lethally irradiated mice transplanted with unseparated or T-cell-depleted syngeneic bone marrow grafts. 294 60

Lipoic acid (Lip), a naturally occurring disulfide compound, was found to augment markedly in vitro antibody responses to sheep erythrocytes (SRBC), dinitrophenyl-Ficoll and trinitrophenyl-lipopolysaccharide (TNP-LPS) as effectively as 2-mercaptoethanol (2-ME) in murine lymphocytes. The mitogenic response to LPS or concanavalin A (Con A) was augmented by Lip only slightly. 2-ME has been reported to facilitate cystine utilization by the lymphocytes, but Lip did not, indicating that the mode of action of Lip is different from that of 2-ME. Lip-augmentation of anti-SRBC response was markedly abrogated when murine lymphocytes were depleted of T cells and cultured in the presence of Con A-conditioned medium containing T cell-replacing factor. The effect of Lip was also diminished in the response to TNP-LPS when the spleen cells were depleted of T cells. These observations suggest that Lip could augment the antibody response by stimulating a T cell subpopulation. This idea was confirmed by the experiment that Lip could enhance helper T cell activity which was induced by culturing murine lymphocytes with the antigen.
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PMID:Augmentation of the antibody response by lipoic acid in mice. I. Analysis of the mode of action in an in vitro cultures system. 294 41


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