Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Genetically susceptible mice become resistant to experimental autoimmune thyroiditis (EAT) induction with mouse thyroglobulin (MTg) and lipopolysaccharide after pretreatment with deaggregated MTg (dMTg). Recent work showed this suppression to be mediated by CD4+ suppressor T cells (Ts). To study Ts action in vivo, we used a rat IgG2a monoclonal antibody (mAb), YTS 177.9, which modulates CD4 antigen in vivo without depleting CD4+ cells. Initial studies showed that after two 1-mg doses of mAb 7 days apart, extensive CD4 antigen modulation of peripheral blood leukocytes occurred within 4 days. Mice given CD4 mAb 24 hr before dMTg (2 doses, 7 days apart) were resistant to EAT induction when immunized with MTg and LPS 20 days later. Also, anti-rat IgG2a titers were reduced following challenge with heat-aggregated rat IgG2a compared to controls. Subsequent analysis of serum in CD4 mAb-treated animals revealed that mAb was present in the circulation for 14 days. Moreover, mice given CD4 mAb and dMTg, then challenged after only 10 days, when CD4 mAb was still circulating, developed a significantly higher incidence of thyroid damage than controls. These findings suggest that modulation of CD4 antigen does not interfere with Ts activation, but the presence of CD4 mAb, at the time of autoantigenic challenge, can interfere with tolerance to EAT induction. Thus, the direct relationship between the presence of CD4 mAb and inhibition of EAT suppression implicates a role for CD4 molecules in the mediation of suppression.
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PMID:Suppression in murine experimental autoimmune thyroiditis: in vivo inhibition of CD4+ T cell-mediated resistance by a nondepleting rat CD4 monoclonal antibody. 168 May 68

In this report we have analyzed the effect of recombinant interleukin 2 (rIL 2) and rIL 2-activated natural killer (NK) cells on the production of immunoglobulin isotypes by lipopolysaccharide (LPS)-stimulated spleen cells from nude mice. We found that rIL 2 induced a dose-dependent increase of IgG2a secretion and a concomitant inhibition of the secretion of other Ig isotypes. The analysis of the phenotype of LPS- and LPS+ rIL 2-stimulated nude spleen cells showed the appearance of a Thy-1+ asialo GM-1+slgM-CD3-CD4-CD8- cell population in the presence of rIL 2. A population with a similar phenotype was generated upon stimulation of spleen cells from nude mice with rIL 2 alone. These cells lysed YAC-1 cells, did not contain the alpha or gamma transcripts encoding the corresponding T cell receptor chains and are therefore NK cells activated by rIL 2. In co-culture experiments, these cells selectively increased the secretion of IgG2a by LPS-stimulated splenocytes from nude mice. The IgG2a induction triggered by rIL 2-activated NK cells, as well as that triggered by rIL 2, were blocked by an anti-interferon gamma monoclonal antibody. Thus, rIL 2 activated-NK cells enhance the production of IgG2a by secreting interferon-gamma.
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PMID:Recombinant interleukin 2-activated natural killer cells regulate IgG2a production. 169 33

The activation of naive CD4 T cells by antigen is a critical step in the initiation of an immune response; it requires both ligation of the T-cell receptor (TCR) and the delivery of co-stimulatory factors by accessory cells. We have examined the role of syngeneic accessory cells in the response of purified normal CD4 T cells to anti-CD3 antibody as ligand. We show that the ability to deliver co-stimulatory signals is inducible in B cells by microbial products such as bacterial lipopolysaccharide (LPS), mitogenic influenza viruses, and synthetic polyinosinic-polycytidylic acid (poly-I:C) as a mimic of viral infection. LPS stimulation for 16 h allows the co-stimulatory activity of B cells to become resistant to paraformaldehyde fixation. LPS induction of fixation-resistant co-stimulator activity requires new protein synthesis, as it is inhibited by cycloheximide. Using the anti-CD45RB mAb 16A as marker for naive and memory CD4 T cells, we show that B cells activated by LPS and by poly-I:C can provide co-stimulatory signal to both naive and memory CD4 T cells. By contrast, zymosan particles, which are known to activate macrophages in a variety of assays, do not activate B cells to become co-stimulatory, but do induce this activity in macrophages. These data demonstrate that a variety of infectious agents or their constituents can induce accessory cells to become co-stimulatory for CD4 T cells. They are interpreted in light of a proposed role for two classes of recognition in the induction of the immune responses, specific recognition of antigens and non-specific recognition of infectious agents. These data support the contention that the immune system uses this mechanism to discriminate infectious non-self from non-infectious self.
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PMID:Microbial induction of co-stimulatory activity for CD4 T-cell growth. 183 51

Mice stressed daily by brief cold water immersions for 1, 8 or 14 days showed changes in immune system function which were dependent on the number of mice per cage, frequency of stress exposures and total number of stress exposures. Changed percentages of spleen B and CD4, but not of CD8 cells were determined when the mice were stressed either once or twice daily. With CD4 cells, increased percentages were seen after stress once daily but a decreased percentage was seen after stress twice daily. Furthermore, the Concanavalin A-stimulated spleen cell mitogenesis was decreased after 1 day of stress in mice stressed once daily as opposed to after 8 and 14 days of stress in mice stressed twice daily. After 14 days of stress, the lipopolysaccharide stimulated mitogenesis was increased if the mice were stressed once daily but decreased if the mice were stressed twice daily. With two mice per cage, we observed a decreased spleen cell mitogenesis after 14 days of stress. With four mice per cage, the spleen cell mitogenesis was decreased after 8 and 14 days of stress. If spleen cell populations from mice stressed twice daily for 8 days were depleted of macrophages and CD4 or CD8 cells, the effect of stress on the mitogenesis was removed from the CD8 cells. Spleen cells of mice stressed for 14 days showed a decreased mitogenesis when depleted of adherent cells and reconstituted with adherent cells from control mice. Furthermore, the adherent cells from these mice had decreased ability to support mitogenesis of adherent cell-depleted spleen cells from control mice as well as a decreased IL-1 production.
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PMID:The effect of various contexts of stress on the mouse spleen lymphocytes and macrophage co-stimulatory activity. 190 2

BDC-6.9 is a CD4-positive T-cell clone, specific for NOD islets, which was isolated from the spleen and lymph nodes of a diabetic NOD mouse. The cells were transplanted in a blood clot adjacent to established NOD islet grafts in diabetic (CBA X NOD)F1 recipients. The BDC-6.9 cells initiated extensive damage to the islet grafts, while a non-islet specific clone transplanted adjacent to grafted islets caused no noticeable damage. In addition, the BDC-6.9 cells initiated similar destruction when injected intraperitoneally, suggesting that they may have some migratory capacity. By introducing these islet-reactive cells into the (CBA X NOD)F1, a non-diabetes prone environment, we hope to clarify the role of the islet-specific CD4 cell as related to islet destruction in vivo.
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PMID:In vivo activity of an islet-reactive T-cell clone. 197 4

HLA-DQw6 transgenic C57BL/6 mice (DQw6-B6) were utilized to define the role of HLA-DQw6 gene product in immune-recognition. To investigate the responsiveness of lymph node cells from C57BL/6 mice (B6) or DQw6-B6 in response to DQw6 molecules expressed in the DQw6-B6, in vitro secondary MLR was performed. The lymph node cells from B6 proliferated in response to spleen cells from DQw6-B6, whereas those from DQw6-B6 did not. These results suggested that DQw6-B6 acquired tolerance to DQw6 molecules. The difference of T cell repertoire between B6 and DQw6-B6 was investigated using mAbs directed against T cell receptor V beta regions, V beta 3, V beta 5, V beta 6, V beta 8, V beta 11 and V alpha 3.2. Although the proportion of V beta 5+ CD8+ T cells and V beta 6+ CD4+ T cells were increased in the B6 anti-DQw6-B6 MLR T cell line, there was no significant difference in the proportion of peripheral T cells expressing each V alpha or V beta region between B6 and DQw6-B6. Both CD4+ and CD8+ long term-cultured T lymphocyte cell lines were generated from lymph node cells of B6 stimulated in vitro by irradiated spleen cells from DQw6-B6. The CD4+ T cell line proliferated in response to spleen cells of DQw6-B6 or L cell transfectant expressing HLA-DQw6 molecules and these responses were completely inhibited by either anti-DQ or anti-CD4 monoclonal antibodies (mAbs) but not by anti I-Ab mAbs. The CD8+ T cell line lysed splenic cells activated by lipopolysaccharide (LPS) from DQw6-B6 spleen cells but not from B6. The CD8+ T cell line also exhibited a cytotoxicity to splenic LPS blast cells from backcross progenies between (DQw6-B6 x DBA1) F1 and DBA1, only when target cells expressed both HLA-DQw6 molecules and H-2b. These observations indicated that recognition of HLA-DQw6 by the CD8+ cytotoxic T cell line was restricted by H-2b. The cytolytic activity of the CD8+ T cell line was inhibited by either anti-CD8 or anti-H-2Db mAbs but not by anti-HLA-DQ nor anti-H-2Kb mAbs. These results show that HLA-DQ transgene products expressed in DQw6-B6 can induce xenogeneic MLR in both CD4+ and CD8+ T cells. The CD4+ T lymphocytes recognize the HLA-DQw6 molecule itself whereas the CD8+ cytotoxic T lymphocytes recognize the HLA-DQw6 gene product in the context of H-2Db.
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PMID:[Immunological function of HLA-DQw6 molecules expressed in DQw6 transgenic C57BL/6 mice]. 202 62

Conventional immunohistochemical analysis of airway intraepithelial class II major histocompatibility complex (Ia) expression demonstrates a morphologically heterogeneous pattern of staining, suggestive of the presence of a mixed population of endogenous antigen presenting cells. Employing a novel tissue sectioning technique in conjunction with optimal surface antigen fixation, we now demonstrate that virtually all intraepithelial Ia staining throughout the respiratory tree in the normal rat, can be accounted for by a network of cells with classical dendritic cell (DC) morphology. The density of DC varies from 600-800 per mm2 epithelial surface in the large airways, to 75 per mm2 in the epithelium of the small airways of the peripheral lung. All the airway DC costain for CD4, with low-moderate expression of a variety of other leukocyte surface markers. Both chronic (eosinophilic) inflammation and acute (neutrophilic) inflammation, caused respectively by inhalation of chemical irritants in dust or aerosolised bacterial lipopolysaccharide (LPS), are shown to be accompanied by increased intraepithelial DC density in the large airways (in the order of 50%) and up to threefold increased expression of activation markers, including the beta chain of CD11/18. The kinetics of the changes in the DC network in response to LPS mirrored those of the transient neutrophil influx, suggesting that airway intraepithelial DC constitute a dynamic population which is rapidly upregulated in response to local inflammation. These findings have important theoretical implications for research on T cell activation in the context of allergic and infectious diseases in the respiratory tract.
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PMID:Studies on the density, distribution, and surface phenotype of intraepithelial class II major histocompatibility complex antigen (Ia)-bearing dendritic cells (DC) in the conducting airways. 203 68

We studied functional and immunohistochemical characteristics of cultured rat microglia. Unstimulated microglia did not proliferate. Microglia stimulated with LCM (L929 conditioned medium: colony stimulating factor-1) had proliferative activity and increased acid phosphatase activity. LPS (lipopolysaccharide) and IFN gamma (interferon-gamma) but did not affect proliferative activity. Immunohistochemically, RCA-1 lectin and GS-1 lectin, which react to beta-D-galactose and alpha-D-galactose respectively, strongly reacted to the cytoplasm and membrane of unstimulated microglia. After stimulation with LCM, microglia elongated processes and decreased response to these lectins. On the other hand, microglia stimulated with LCM showed increased reactivity to monoclonal antibody of vimentin. Microglia stimulated with LPS had round shape and had response to these lectins and vimentin. Microglia stimulated with IFN gamma had adhesive activity and weakly stained with these lectins but not with vimentin. ED-1 (monoclonal antibody of rat monocytes/macrophages) reacted to unstimulated and stimulated microglia. In flow cytometry, unstimulated microglia expressed OX-18 (MHC class I) and W3/25 (CD4) antigen. After stimulation with IFN gamma, microglia were induced to express these antigens. CD4 antigen is a marker of helper/inducer T cells and thought to be a receptor of HIV. The results that microglia had CD4 antigen which was further induced with IFN gamma are important to investigate infection of the CNS with HIV. OX-6 (Ia) antigen was induced with IFN gamma. This indicates that the microglia plays a central role in the CNS immune reaction. These characteristics of cultured rat microglia provide useful informations to investigate the pathogenesis of the CNS disorders.
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PMID:[Functional and immunohistochemical studies of cultured rat microglia]. 206 Feb 34

This review suggests that infections are potent immunomodulators by causing significant alterations in one or more mediators of homeostasis and that an effective antibiosis may be a potent immunomodulator, albeit indirectly. When large numbers of microorganisms are killed, their enzymes and toxins are rapidly released and activate the immune system. The septic syndrome and the potentially progressive states of septic shock, acute respiratory distress syndrome and multiple organ system failure illustrate the biological response modulating (BRM) activity of both infection and antibiotic. Enhancement of phagocytosis and intracellular killing would be a useful immunomodulatory activity for antibiotics. Equally useful would be the capacity of the antibiotic to bind or inactivate bacterial lipopolysaccharide (LPS) to diminish monocyte release of tumour-necrosing factor (TNF) at a rate equal to or faster than the killing effect of the antibiotic on bacteria. For other types of immune deficiencies, such as are observed in HIV-positive patients with secondary bacterial, fungal and viral infections, modulation of viral receptors including HIV-R on CD4 lymphocytes accompanied by their up-regulation, enhancement of interferon (IFN) and natural killer (NK) function and inhibition of CD8 suppressor activity would be important activities. The classic example of polymyxin as an immunomodulating, albeit toxic, antibiotic offers a rational and definitive basis for the concept. In-vitro data on cefodizime, a third generation cephalosporin that achieves good tissue levels, are presented and show the ability of the intact antibiotic, as well as its immunomodulating side-chain, to down-regulate TNF and interleukin 1 (IL-1) released from human monocytes by lectin-activated lymphocytes, LPS and IFN.
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PMID:Antibiotics as biological response modifiers. 207 50

Concentrations of IgM and IgG isotypes were determined by capture ELISA in plasma of Swiss, BALB/c and C58/M mice. Plasma IgG isotype concentrations, especially of IgM, IgG1 and IgG2a, varied considerably between mouse strains, batches of mice of the same strain and individual mice and as a function of age. Infection of the mice with LDV, which is known to replicate primarily in a subpopulation of macrophages, consistently resulted in a rapid elevation of plasma IgG2a (or of IgG2b in some Swiss nu/+ mice), but no plasma IgG increases were observed in mice immunized with inactivated LDV. Plasma IgG2a elevation after LDV infection was greatly delayed and reduced by depletion of the mice of CD4+, but not of CD8+, T cells by administration of protein-G-purified anti-CD4 or anti-CD8 mAbs, and completely inhibited by repeated treatment of the mice with cyclophosphamide. Treatment with anti-CD4 mAbs, or cyclophosphamide also greatly reduced the production of anti-LDV antibodies, while not significantly affecting the replication of LDV in these mice. Nude Swiss mice also failed to produce anti-LDV antibodies, though supporting normal LDV replication. Plasma IgM, IgG1, IgG2a and IgG2b levels increased in LDV-infected nu/nu mice, but similar changes were observed in uninfected mice. The results indicate that the LDV-induced polyclonal activation of B cells requires productive LDV infection of mice and is, at least partly, dependent on functioning CD4+ cells. They suggest that productive infection of the LDV-permissive subpopulation of macrophages leads to the activation of CD4+ T lymphocytes of subset 1 and their Spleen cells from 5-day LDV-infected BALB/c mice incorporated [3H]thymidine 2-3 times more rapidly in vitro than spleen cells from companion uninfected mice, whereas their responses to concanavalin A and lipopolysaccharide were reduced 60-70%.
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PMID:Polyclonal B cell activation of IgG2a and IgG2b production by infection of mice with lactate dehydrogenase-elevating virus is partly dependent on CD4+ lymphocytes. 207 77


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