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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since polyclonal B-cell activators (PBA) require macrophages to induce modifications in the lymphocyte in vitro primary response to thymus-dependent antigens, we have investigated whether PBA act directly on macrophages. [14C]glucosamine uptake by guinea pig peritoneal adherent cells after stimulation with purified protein derivative (PPD), lipopolysaccharide (LPS), and dextran sulfate (DxS) was tested. PPD produced an increased [14C]glucosamine uptake, whereas LPS and DxS did not. According to our experiments, (a) PPD does not require the presence of lymphocytes to stimulate macrophages; furthermore, when lymphocytes were present in a concentration higher than 5%, a suppressor effect in the glucosamine uptake was found, and (b) there was no significant difference between the findings when peritoneal adherent cells were cultured in normal medium and in supernatant of lymphocyte cultures stimulated with PPD.
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PMID:Direct activation of guinea pig macrophages by a B-cell mitogen. 30 78

Antiserum specific for hamster thymus-derived lymphocytes, prepared by immunizing rabbits with hamster brain tissue, was cytotoxic to hamster thymocytes greater than lymph node cells greater than spleen cells, while virtually non-reactive against bone marrow. This antiserum inhibited spleen cell response to the T cell mitogen, phytohemagglutinin, but not to lipopolysaccharide, a B cell mitogen.
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PMID:Induction of hamster T cell-specific antiserum in rabbits using hamster brain tissue. 30 34

Using an in vitro culture technique, mouse thymus graft cells were co-cultured with peripheral blood lymphocytes in the presence of phytohaemagglutinin (PHA). The persistent PHA-responsive thymus graft population (Elliott, 1973) was shown to be able to response to other T-cell mitogens (Con A, pokeweed mitogen, staphylococcal enterotoxin B), but not to E. coli lipopolysaccharide a known B-cell mitogen. The percentage of persistent PHA-responsive cells did not alter during 5 days in culture and was relatively unaffected by either hydrocortisone or anti-lymphocyte serum treatment in vitro. In allogeneic thymus grafts (AKR leads to CBA), persistent PHA-responsive cells could be demonstrated, which were destroyed when incubated with CBA anti theta AKR serum and complement. When thymus graft cells were allowed to sediment on a 0.2-2 per cent BSA gradient, it was seen that the PHA-responsive population sedimented faster than the bulk of thymus graft cells. Some separation could be obtained on this gradient between the persistent and non-persistent PHA-responsive cell populations.
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PMID:Ther persistent PHA-responsive population in the mouse thymus. i. Characterization of the population. 30 8

Albumin, transferrin, and lipids can replace serum entirely for support of LPS-stimulated murine B lymphocytes in culture. In the presence of these compounds, growth and maturation to IgM and IgG secretion, induced by lipopolysaccharide (LPS), occurs at the same or higher efficiency in serum-free conditions as in conventional serum-containing medium, even at relatively low cell concentrations. In contrast to the rapid disappearance of LPS reactivity in conventional serum-containing medium, responsiveness remains at initial levels in serum-free conditions for 2 days before slowly declining. Overall lymphocyte survival is also markedly prolonged. In the presence of thymus "filler" cells, the serum-free conditions permit growth of every LPS-responsive cell to a clone of Ig-secreting cells at dilutions as low as a single reactive B cell per culture. The results have several important implications. These include the establishment for the first time of transferrin as a requirement for B lymphocyte responses in culture, and the availability now of conditions for the assay isolation of cell products regulating lymphocyte function, free of interference from undefined serum components.
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PMID:Complete replacement of serum by albumin, transferrin, and soybean lipid in cultures of lipopolysaccharide-reactive B lymphocytes. 30 62

Nonirradiated B-lymphocyte-deficient CBA/N mice given T6T6 chromosome-marked normal CBA/CaHN spleen cells became lymphoid chimeras exhibiting donor-type mitoses. Normal CBA/CaHN recipients did not exhibit significant numbers of donor-type mitoses. The lymphoid cell chimerism in the CBA/N host appeared in spleen, lymph nodes, and Peyer's patches, but not in marrow or thymus. Stimulation of CBA/N-recipient spleen cells in vitro suggested that the chimerism involved donor T6T6 cells which were responsive to the B-lymphocyte mitogen, lipopolysaccharide, but not to the T-lymphocyte mitogen, phytohemagglutinin. These data indicate that stable, long-term chimerism of a specific class of lymphocytes is possible in nonirradiated, B-lymphocyte-deficient CBA/N mice.
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PMID:Induction of partial chimerism in nonirradiated B-lymphocyte-deficient CBA/N mice. 30 63

Mice injected subcutaneously with 1 x 10(8) sheep red blood cells (SRBC) developed high levels of delayed-type hypersensitivity (DTH) to SRBC 4-8 days after injection. Such DTH was suppressed when 100 microgram lipopolysaccharide (LPS) was injected intravenously 1-2 days before or at the time of SRBC injection. This suppression of DTH was transferable by spleen, lymph node, thymus and bone marrow cells to sensitized or normal syngeneic recipients, but could not be transferred by serum. Suppressor cells were not induced by LPS alone or SRBC alone, and they were antigen-specific since DTH to chicken red blood cells was not affected. The suppressor cells appeared in the spleen in optimum number 3-4 days after induction. They were theta-negative and Ig-positive as judged by antiserum plus complement treatment and by Ig rosette separation. Attempts to obtain soluble suppressor factor from the suppressor cells by sonication or in vitro incubation were unsuccessful. Mitomycin C treatment of the suppressor cells completely abolished the suppressor activity. Thus, LPS, in conjunction with antigen, appears to induce a population of specific suppressor B cells which are capable of regulating T cell function.
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PMID:Regulation of delayed-type hypersensitivity IV. Antigen-specific suppressor cells for delayed-type hypersensitivity induced by lipopolysaccharide and sheep erythrocytes in mice. 31 2

This paper deals with the CBA/N mice, a strain bearing a genetic defect in their B-cell compartment. By using a previously described system we have been able to show that the immature cells of CBA/N mice are functionally indistinguishable from normal immature cells, in that both can be triggered to respond to thymus-independent (TI) antigens, provided they are supplied with helper T cells. When the maturation is completed, CBA/N B cells are unable to respond to TI antigens (like lipopolysaccharide and polyvinyl pyrrolidine) irrespective of the presence of helper T cells, whereas normal mature B cells have grown able to respond without any help. These data allow us to reject the hypothesis that CBA/N mice are arrested at an immature stage and clearly support the idea that they have deviated during development so that only thymus-dependent B cells develop.
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PMID:Ontogeny of B cells in CBA/N mice. Evidence for a stage of responsiveness to thymus-independent antigens during development. 31 89

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.
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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.
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PMID:A B lymphocyte mitogen extracted from a fungus Peziza vesiculosa. 31 98

Fifty-three organ, cellular and activity indices were assessed in aging mice of 8 strains and hybrids (5 inbred strains, 1 random bred strain and 2 hybrids of inbred strains) in an attempt to determine which aspects of immunologic aging are characteristic of the species. The results indicate that thymic weight, cellular, and activity indices exhibit a statistically significant negative correlation with age for mice of all 8 strains and hybrids; and B cell cellular indices show a statistically significant positive correlation with age for all mice, while the B cell activity index, lipopolysaccharide response, is dependent on the strain or hybrid. This correlation study supports the view that the T cell component of the immune system deteriorates with age while the B cell component remains relatively intact. Further, the results suggest that thymic aging is a characteristic of the mouse species and that the intrinsic "clock" for immunologic aging resides in the thymus, because most splenic and lymph node T cell activity and cellular indices are associated with thymic weight and cellular indices. Finally, the findings that indices which correlate best with age show the same trend for all strains and hybrids examined suggest that (a) if randomly occurring somatic mutation does play a role in immunologic aging, its influence is limited, and (b) genetic factors not easily influenced by environmental factors regulate immunologic aging.
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PMID:Age-related changes in the immune system of mice of eight medium and long-lived strains and hybrids. I. Organ, cellular, and activity changes. 31 45


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