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)

Escherichia coli lipopolysaccharide (LPS), a polyclonal B cell activator, has been employed to achieve in vitro stimulation of autoantibody-secreting B cells in young adult and aged mice of long-lived strains as assayed in a hemolytic plaque technique to syngeneic mouse erythrocytes. Aged 21- to 24-month-old C57BL/6J and (C57BL/10Sn x C3H/HeDiSn)F1 mice were found to express 3 to 4 times as many LPS-induced plaque-forming cells (PFC) to autologous erythrocytes than did younger 6-month-old animals. With the use of cyclophosphamide (CY), a significant enhancement of auto-PFC production in young mice occurred, approaching levels found in non-CY-treated old mice. Thus, autoreactive clones of lymphocytes exist in the spleens of young adult mice, but under normal circumstances produce little autoantibody. The situation in aged members of these strains, therefore, does not seem to involve an actual increase in numbers of autoreactive B cells, but may possibly involve some form of deregulation, permitting increased age-related expression of autoreactive lymphocyte clones.
 ...
PMID:Aging increases expression of LPS-induced autoantibody-secreting B cells. 31 85

The purified protein derivative of tuberculin (PPD tuberculin) stimulates approximately one of two lipopolysaccharide (LPS)-activated B-cell blasts of C57BL/6J nu/nu spleen cells to continued clonal growth and maturation to IgM and IgG secretion. It alwo stimulates background, in vivo-activated large cells of normal C57BL/6J nu/nu spleen to growth and Ig secretion, at a frequency of approximately 1 of 100 large spleen cells. PPD tuberculin, therefore, is a polyclonal B-cell activator for B-cell blasts. Many single murine splenic B cells (approximately 50%) appear to have reactivities, and therefore probably receptors, for LPS and PPD tuberculin. PPD tuberculin does not stimulate small, resting B cells to growth as measured by the number of cells in culture and by thymidine uptake. However, it stimulates approximately one-fourth of all spleen cells to blast transformation. The large-size blast cells secrete IgM and, therefore, form plaques in the protein A plaque assay. IgG-secreting, plaque-forming cells develop at later stages of stimulation, indicating that the switch from IgM to IgG may occur without division in single, stimulated B cells. Stimulation of resting B cells to maturation by PPD tuberculin is polyclonal. Thus, approximately 1 in 10(2) IgM-secreting plaque-forming cells form plaques with trinitrophenyl-substituted sheep erythrocytes, 1 in 450 do so with horse erythrocytes, and 1 in 10(3) with sheep erythrocytes. Furthermore, the number of Ig-secreting cells developing from small, resting cells without growth in cultures with or without filler thymus cells suggests polyclonal activation by PPD tuberculin to maturation only of at least one out of four small, splenic B cells.
 ...
PMID:The purified protein derivative of turberculin, a B-cell mitogen that distinguishes in its action resting, small B cells from activated B-cell blasts. 31 90

A water-soluble mitogen was extracted with hot-water from the fruiting bodies of a fungus, Peziza vesiculosa, collected in the wild. The active substance, named vesiculogen, was able to stimulate selectively murine B cells because mitogenic activity was observed in the spleen cell cultures of congenitally athymic nude mice, but not in the thymus cell cultures. The possibility that the mitogenicity of vesiculogen was due to lipopolysaccharide was denied completely by the following evidence: 1) lipopolysaccharide in vesiculogen was undetectable(less than 0.001% in the Limulus test), 2) vesiculogen was able to stimulate strongly DNA synthesis of spleen cells from C3H/HeJ mice, and 3) the mitogenic activity of vesiculogen was not inhibited by polymyxin B. Vesiculogen increased antigen-nonspecifically the number of direct plaque forming cells to sheep erythrocytes, horse erythrocytes, and trinitrophenylated-horse erythrocytes. This result shows that vesiculogen acts as a polyclonal B cell activator on murine spleen cells.
 ...
PMID:A B lymphocyte mitogen extracted from a fungus Peziza vesiculosa. 31 98

Fc receptor positive alloantigen-activated T cells release an immunoglobulin binding factor (IBF) which suppresses in vitro antibody synthesis. The present work was undertaken to approach the mechanisms by which IBF suppresses the response, and we obtained the following results. First, IBF does not inhibit DNA synthesis in lipopolysaccharide stimulated spleen cells while suppressing the polyclonal plaque response, indicating that IBF does not interfere with B-cell proliferation. Second, antibody synthesis by spleen cells from Nude (nu/nu) mice, stimulated with sheep red blood cells triggered by concanavalin A induced T-cell replacing factor (TRF) was suppressed by IBF, indicating that the factor does not need mature T cells to express its activity. Kinetics experiments showed that IBF does not destroy TRF but rather acts sequentially with the helper factor on the late phase of the differentiation of B cells to antibody producing cells.
 ...
PMID:Regulation of antibody synthesis to sheep red cells in cultures of nu/nu spleen cells by T-cell replacing factor (TRF) and immunoglobulin-binding factor (IBF). 31 81

The frequency of normal murine B lymphocytes initiating growth in diluted suspension cultures in the presence of a B cell mitogen, such as lipopolysaccharide, can be increased approximately 10(4) fold by the addition of 2 X 10(6) normal thymus cells per ml. This increase in the frequency of growing cells by thymus cells can also be observed with X63-AG8 myeloma tumor cells secreting IgG1. Thus thymus cells may not contribute growth-stimulating factors, but may supply growth-supporting factors. Culture medium and plastic dishes can be conditioned by preincubation with thymus cells for a day after which the thymus cells may be omitted from further culture for maximal B cell growth. Irradiation of thymus cell abolishes their growth-enhancing properties. Thymus cells can be syngeneic and allogeneic with the growing B cells. The frequency of growing LPS-reactive, normal B cells in spleen of 6-8 week old C3H/Tif mice was determined by limiting dilution analysis to be one of three splenic B cells. With this limiting dilution analysis, it was also shown that the cloning efficiency of XB3-AG8 myeloma tumor cells in suspension culture in the presence of thymus cells is practically 100%. Analysis of the growth kinetics of single clones of LPS-reactive, normal B cells shown that these B cells divide every 18 hr. Within the first 126 hr of growth, every B cell in the clone divides, and every dividing B cell in this clone secretes sufficient immonoglobulin to form a hemolytic plaque. The conditions of in vitro suspension cultures of murine B lymphocytes are therefore perfect to the extent that every B cell capable of growth will grow as a single clone.
 ...
PMID:Clonal growth and maturation to immunoglobulin secretion in vitro of every growth-inducible B lymphocyte. 31 12

The influence of synthetic polymeric agents on the immune responsiveness of congenitally athymic (nude) mice was investigated by determining the effects of in vivo treatment with polynucleotides and polymeric haptenated antigens on splenic theta-bearing cells, on mitogen stimulation and on plaque-forming cell responses to thymic dependent and thymic independent antigens. Contrary to in vitro data, no evidence was obtained to demonstrate in vivo restoration of these immune parameters by the use of non-specific immune enhancers. Further, despite the continued release of lipopolysaccharide from the bowel, older nude mice (10 months old) demonstrated no acquisition of improved T-cell function. Nude mice responded well to the thymic independent antigen p-azobenzenearsonate-N-acetyl-tyrosylglycylglycine (A-TGG) Ficoll. Finally, the class specific responses to the thymic independent antigen DNP-Ficoll were significantly different from those of nu/+ littermate controls, indicating the importance of thymic influences upon the class switching of immunoglobulin responses.
 ...
PMID:The effects of synthetic polymeric agents on immune responses of nude mice. 32 46

The adjuvant and immunostimulating activities of a glycoprotein preparation (GP) extracted from Klebsiella pneumoniae have been studied. When injeted with an ovalbumin in incomplet Freund adjuvant emulsion, the GP induces delayed hypersensitivity to the antigen and increases the level of antibody developed. When it is injected before the antigen to C57Bl/6 mice, the GP provokes an increase of plaque forming cells, rosette forming cells, and antibody responses. With the doses that are used, no mechanism can be detected which could be due to an antigenic activity of the GP. The immunostimulating properties decribed cannot be due to a lipopolysaccharide since the preparation contains less than 1 p. 100 of endotoxin.
 ...
PMID:[Immunostimulating activities in vivo of extract from Klebsiella pneumoniae]. 32 82

A role for antigen in the generation of fully mature splenic type B cells has been shown. In adoptive transfer experiments, cells from bone marrow or fetal liver required a longer period to give an anti-sheep red blood cell plaque-forming cell (PFC) response than those from spleen. This delay was not overcome by allowing the cells a 7-day sojourn in the irradiated host before antigen challenge. A two-stage protocol was designed in which the in vivo generation of fully mature cells could be measured by their ability to give PFC in lipopolysaccharide-stimulated cultures in vitro. These experiments showed that a critical factor which influences the final differentiation of bone marrow or fetal liver cells into mature, splenic type B cells is exposure to antigen.
 ...
PMID:Ontogeny of the antibody-forming cell line in mice. III. The generation of mature anti-sheep red blood cell-specific B cells is antigen-dependent. 32 62

The fungus metabolite cyclosporin A is a small cyclic peptide acting as a novel antilymphocytic agent. It is effective following either parenteral or oral administration in mice, rats and guinea-pigs. The suppressive effect after short and prolonged treatment on plaque-forming cells, the inhibition of the secondary humoral response and the reversibility of its effect on haemagglutinin formation is demonstrated. Cyclosporin A inhibits delayed hypersensitivity skin reaction to oxazolone (primary and secondary responses) in mice and to tuberculin in guinea-pigs. Its failure to suppress antibody synthesis to lipopolysaccharide antigens in nude mice suggests a selective effect on T cells. High doses of the compound affect the haemopoietic tissues very weakly as shown by the bone marrow and stem cell numbers in mice, which finding markedly contrasts with most other immunosuppressive and cytostatic drugs.
 ...
PMID:Effects of the new anti-lymphocytic peptide cyclosporin A in animals. 32 80

A marked reduction in the number of plaque-forming cells from spleens of mice infected with Schistosoma mansoni to sheep erythrocytes (SRBC) and lipopolysaccharide from Escherichia coli was observed. This reduction coincided with the late stages of the infection and was also observed in unisexual infection with male worms. Treatment of the animals with a schistosomicidal compound (oxamniquine) almost completely abolished the immunosuppression. The suppression could be induced by administration of 60 microgramg protein from worm membrane preparations (24 h before SRBC injection), but not by egg-extract injection. When the crude membrane preparation was injected 48 h before or 0 to 24 h after the SRBC challenge, the immunosuppression was not observed. Significant reduction of footpad swelling was also noted in infected mice when injected with SRBC.
 ...
PMID:Immunosuppression mediated by adult worms in chronic schistosomiasis mansoni. 32 99


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>