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)

A substance which was mitogenic for murine B lymphocytes in the presence of 2-mercaptoethanol was isolated from agar. Stimulating activity of this material was stable to proteolysis or protein denaturants but was destroyed by periodate treatment. Agar-derived mitogen stimulation was distinct from that obtained with dextran sulfate or lipopolysaccharide and may define different populations of B lymphocytes.
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PMID:Growth of B-lymphocytes clones in semisolid culture is mitogen dependent. 108 21

The association between various sociodemographic variables and the presence of anti-Shigella sonnei lipopolysaccharide (LPS) antibodies was examined in a random sample (N = 383) of male Israeli conscripts. Of the male conscripts, 190 (49.6%) had pre-existing antibodies against S. sonnei LPS (defined as HA titres of greater than or equal to 1:10 after treatment of sera with 2-mercaptoethanol). Univariate analysis revealed a significant positive association between the presence of humoral anti-S. sonnei LPS antibodies and sociodemographic variables including Eastern origin (p = 0.007), low socioeconomic status (p = 0.0016), and the number of siblings (p = 0.023). When multiple logistic regression was used to control simultaneously for the effects of the other variables, ethnic origin emerged as the strongest correlate of anti-S. sonnei LPS antibodies. On the other hand, the association of the sociodemographic variables in subjects suffering from S. sonnei infection during their military service, was in the opposite direction (p less than 0.001 for both socioeconomic status and ethnicity). These findings suggest differences between subpopulations in acquired immunity to S. sonnei due to differences in exposure to the homologous organism prior to military service.
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PMID:Sociodemographic factors associated with serum anti-Shigella lipopolysaccharide antibodies and shigellosis. 191 63

Although their mechanism of degradation may differ, both the SN1 alkylators, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-nitroso-N-methylurea (MNU), and the SN2 alkylators, dimethyl sulfate (DMS) and methyl methanesulfonate (MMS), spontaneously decompose under aqueous conditions to the methyldiazonium ion or a direct methylating intermediate, respectively. Thus, these agents serve as useful probes to investigate the immunosuppressive potential of the putative primary reactive intermediate of dimethylnitrosamine (DMN) metabolism, the methyldiazonium ion. The effects of these direct alkylating agents on the in vitro immune response were characterized. Direct addition of both the SN1 and SN2 alkylators to naive B6C3F1 murine splenocytes produced a dose-dependent suppression of the in vitro antibody-forming cell (AFC) response to the T-dependent antigen, sheep erythrocytes (sRBC), T-independent antigen, dinitrophenyl (DNP)-Ficoll, and the polyclonal activator, lipopolysaccharide (LPS). The T-dependent and T-independent responses proved to be more sensitive than the polyclonal response to the effects of these compounds, except for MNNG in which all 3 antibody responses were equally affected. The suppression of the AFC response for all antigens was unaffected by the addition of 2-ME, and was observed at concentrations below those affecting viability, although at the highest concentrations an effect on viability was often observed. The addition of MNNG to the T-dependent AFC response at any time within the first 96 h produced a marked suppression, while the addition of DMS to cultures was only effective in suppressing the AFC response if added within the first 24 h. MNNG and DMS suppressed the proliferative responses to both B-cell (LPS) and T-cell (Concanavalin A; Con A) mitogens, as well as in the mixed lymphocyte response (MLR). In addition, a positive correlation between immunosuppression and DNA damage, as measured by single-strand breaks, was observed. Although these compounds produced suppression of in vitro immune responses, their profile of activity on immunocompetence and DNA damage was different from that associated with DMN and thus, the direct alkylators may not prove to be useful models to elucidate the mechanism of the DMN-induced immunosuppression.
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PMID:Characterization of the effects of direct alkylators on in vitro immune responses. 239 23

ATPase activity of elementary bodies (EBs) of Chlamydia trachomatis was investigated by using high-resolution 31P nuclear magnetic resonance spectroscopy. ATPase activity was detected in EBs of C. trachomatis serovars A, B, and L2 after treatment with the reducing agents 2-mercaptoethanol and glutathione. ATPase activity was oligomycin sensitive and magnesium ion dependent. EBs heated at 60 degrees C for 10 min or pretreated with Triton X-100 before exposure to 2-mercaptoethanol did not exhibit ATPase activity. Monoclonal antibody to the major outer membrane protein abrogated ATPase activity of EBs, whereas monoclonal antibody to chlamydial lipopolysaccharide only marginally reduced the level of ATPase activity. These findings suggest that EBs possess intrinsic ATPase activity and that cysteine-rich outer membrane proteins of EBs are important in the regulation of ATPase activity. The major outer membrane protein may be the major route through which ATP accesses ATPase.
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PMID:High-resolution 31P nuclear magnetic resonance study of Chlamydia trachomatis: induction of ATPase activity in elementary bodies. 253 Jan 75

A murine monoclonal IgM antibody recognizes an antigen (Mo3e) found on the surface of human peripheral blood monocytes stimulated with phorbol 12-myristate 13-acetate (PMA), lipopolysaccharide and muramyl dipeptide and blocks the monocyte response to migration inhibitory factor (MIF). We utilized Western blot and immunoprecipitation analyses of whole cell lysates to investigate the biochemical nature of this monocyte antigen. Two distinct bands (75 kDa and 50 kDa) were detected by anti-Mo3e after monocyte lysates were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transblotted onto nitrocellulose paper. Stimulation of monocytes with PMA resulted in a marked increase in the amount of the 50-kDa species. Immunoprecipitation of Mo3e from lysates of surface-iodinated cells demonstrated one broad band at 55-80 kDa which increased after PMA stimulation. The epitope identified by anti-Mo3e was resistant to 2-mercaptoethanol and heat treatment (100 degrees C/5 min) and was sensitive to trypsin or papain treatment. Two-dimensional SDS-PAGE analysis revealed that the 75-kDa species has an isoelectric point of 7.0 and the 50-kDa species is more acidic with an isoelectric point of 5.3. These results indicate that anti-Mo3e antibody defines unique monocyte proteins that may play a role as suggested by previous studies, in monocyte activation and responsiveness to MIF.
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PMID:Identification of a human monocyte antigen (Mo3e) associated with cellular activation and lymphokine responsiveness. 265 70

Mouse spleen lymphocytes require 2-mercaptoethanol for maximal mitogenic activation in vitro. Previous studies indicate that the lymphocytes are defective in the cystine transport activity and that they require 2-mercaptoethanol to utilize cystine. 2-Mercaptoethanol catalytically carries cysteine moiety into the cells in a mixed disulfide form. Because cysteine is easily oxidized to cysteine in the culture medium, it has been not easy to precisely examine the effect of near-physiological concentrations of cysteine on the activation of lymphocytes. By controlling the cysteine content in the medium, we have reviewed the effect of cysteine to see if cysteine replaces 2-mercaptoethanol in enhancing the DNA synthesis of lipopolysaccharide-stimulated lymphocytes. It was found that cysteine was less effective than 2-mercaptoethanol, and that cysteine fully replaced 2-mercaptoethanol when a selenium compound was supplemented. The effects of cysteine and selenium compounds were apparently independent and additive. Among the selenium compounds examined, sodium selenite and L-selenocystine were much more effective in stimulating DNA synthesis than sodium selenate and L-selenomethionine.
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PMID:Full replacement of 2-mercaptoethanol by cysteine plus selenium compounds in augmenting DNA synthesis of mitogen-stimulated mouse spleen lymphocytes. 277 26

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

The secretion of immunoglobulin (Ig) from cultured mononuclear cells by lipopolysaccharide (LPS) stimulation is inhibited by monoclonal nonspecific suppressor factor (MNSF), a lymphokine produced by murine T cell hybridoma. In an attempt to develop a murine monoclonal antibody (MAb) with specific reactivity against MNSF, a cell fusion technique that incorporated immune murine splenocytes and HAT-sensitive murine myeloma cells was used. Cross-reactivity experiments confirmed that the MAb (MO6) does not bind to unrelated proteins such as bovine serum albumin, mouse IgG, and murine interferon-gamma (IFN-gamma). There are no effects when anti-IFN-gamma antibodies are used with MNSF. As far as biological activity is concerned, MO6 inhibits in vitro the activity of MNSF in terms of the Ig secretion from cultured lymphocytes. By using MO6, affinity chromatography and immunoblotting were performed. The MNSF on the SDS-PAGE showed a band with m.w. of approximately 70,000, indicating the formation of an aggregate in saline; but after treatment with 0.4 M pyridine-acetic acid buffer, separate bands of 24,000 and 16,000 daltons were evident. Therefore MO6 recognizes 70,000 and both 24,000 and 16,000 daltons. Thus we confirmed by using this MAb and affinity chromatography, the existence of human counterpart, human nonspecific suppressor factor (hNSF), in supernatant from concanavalin A-stimulated T cells. When hNSF was fractionated by high pressure liquid chromatography (HPLC), the activity was found in a region corresponding to 70,000 daltons. However, when fractionated in pyridine-acetic acid buffer, hNSF activity was distributed in a slightly wider range of 15,000 to 30,000 daltons. Physicochemical analysis showed that the purified hNSF is resistant to either heating at 56 degrees C or to 2-mercaptoethanol treatment; however, it is labile to acidification at pH 2.0 and is also sensitive to protease treatment, the characteristics of which were similar to those of murine MNSF. Thus MO6 was confirmed to be a pertinent tool for isolation of hNSF, as well as for murine MNSF.
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PMID:Characterization of monoclonal nonspecific suppressor factor (MNSF) with the use of a monoclonal antibody. 310

The addition of 0.5% globulin-free (GF-BSA) or 0.5% delipidated BSA (D-BSA) to short-term murine bone marrow (BM) (cultures) increased the number of plaque-forming cells (PFC) responding to trinitrophenylated lipopolysaccharide (TNP-LPS) 2-5-fold (1.1 X 10(4)-2.7 X 10(4) PFC per 10 X 10(6) nucleated BM cells). Although it was necessary to continue to supplement these cultures with 5% fetal calf serum (FCS), the inclusion of the aforementioned BSA preparations provided enhanced PFC production for all lots of FCS tested. Similarly, these preparations of BSA made it feasible to also culture BM in autologous mouse sera (MS) or in medium without 2-mercaptoethanol (2-ME) if in the latter case the D-BSA was pretreated with 2-ME. Thus, the inclusion of GF-BSA or D-BSA in short term cultures of BM not only substantially increased the number of Ig-secreting B cells produced in response to TNP-LPS but seemed to eliminate the need to screen for supportive batches of FCS or MS. These preparations of BSA also facilitated hapten specific PFC responses of fetal liver cultures.
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PMID:Improved plaque production for short-term bone marrow and fetal liver cultures. 339 48

Thymocytes from Balb/C mice were activated in vitro by Zn++ as noted by the several-fold increases in 3H-thymidine incorporation at 144 h of culture. Thymocyte activation by Zn++ required the presence of 2-mercaptoethanol (2-ME) and bacterial lipopolysaccharide (LPS) in concentrations as low as 1.0 ng/ml. Thymocytes were not stimulated by these agents in the absence of Zn++. Bovine serum products, thought to contain trace amounts of LPS, appeared to satisfy this LPS requirement. Interleukin 1 (IL 1) could not replace LPS as a cofactor. Thymocytes did not respond to Hg++ under the culture conditions used here. Thymocyte subpopulation studies showed that cell preparations enriched for peanut lectin receptor-negative, mature thymocytes were activated by Zn++ and required LPS for the response.
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PMID:Heavy-metal mitogenesis: thymocyte activation by Zn++ requires 2-mercaptoethanol and lipopolysaccharide as cofactors. 349 67


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