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

Friend leukemia virus (FLV) leukemogenesis was prevented by treatment of the virus with Concanavalin A (Con A). Mice infected with the lectin-treated virus, however, showed evidence of a dormant infection since infectious virus could be recovered for as long as 100 days. Humoral immune responses to sheep erythrocytes (SRBC), a thymus-dependent antigen, and to E. coli lipopolysaccharide (LPS), a thymus-independent antigen, were depressed (approximately 80-90%) in mice given the Con A-treated FLV. Cell transfer studies indicated that the impaired responsiveness to SRBC was related to a defect in B-lymphocyte function, similar to the impairment in mice infected with untreated FLV. The mitogenic response of splenocytes from Con A-FLV mice to E. coli LPS was also depressed as was the ability of Ig-bearing spleen cells to redistribute these immunoglobulin receptors into polar caps. The impaired immune responsiveness in the Con A-FLV infected mice appeared associated with the persistent virus infection and not to neoplastic transformation generally associated with leukemogenic process.
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PMID:Discussion paper: impairment of B-lymphocyte functions in concanavalin A-treated friend virus infected mice. 108 87

Removal of adherent cells or complement-mediated killing of rabbit thymus lymphocyte antigen (BTLA) bearing rabbit T lymphocytes did not abolish the responsiveness (increased thymidine incorporation) of lymphoid cells to antibody against immunoglobulin allotype, Nocardia water-soluble mitogen (NWSM), pneumococcal polysaccharide SIII (PPSIII), S. abortus lipopolysaccharide (LPS), lipid A conjugated to bovine serum albumin and a crude preparation containing C polysaccharide from the cell wall of Diplococcus pneumoniae. Isologous and heterologous antisera, directed against different portions of the Ig receptor, differed in their capacity to enhance thymidine incorporation. The difference in mitogenicity of these antisera was discussed in terms of the accessibility of cell-bound immunoglobulin receptor sites. Spleen cells, responsive to anti-allotype (Ab4) antiserum and B-cell mitogens, NWSM and PPSIII, were characterized by velocity sedimentation. The mean volume of NWSM- and PPSIII-responsive cells was larger than that of the cells responsive to anti-allotype antiserum. Fractionation of spleen cells on glass bead columns yielded a population of non-adherent cells which were two to six times as responsive to anti-Ab4 antiserum as the original spleen cell suspension. The responsiveness of peripheral blood lymphocytes to anti-Ab4 antiserum was significantly greater than that of spleen cells. On the other hand, spleen cells were more responsive to PPSIII than were cells from the peripheral blood, the popliteal and the mesenteric lymph nodes.
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PMID:Rabbit lymphoid cells. II. Anti-allotype antisera, lipopolysaccharide and other bacterial and fungal mitogens as probes for the identification of B-cell subpopulations. 108 19

The alloantigenic specificity Ly-4.2 can be detected on a proportion of lymphocytes by the antiserum (BALB/c times SWR)F1 anti-B10.D2. In the preceding study it was shown that these lymphocytes were not thymus-derived (T) cells, as they were Thy-1 (theta)(-), and were therefore presumably B (bone marrow-derived) cells. Evidence is now presented for the reaction of the Ly-4.2 antiserum with functional B cells. Thus, the LY-4.2 and Thy-1.2 specificities were detected on antigen-binding rosette-forming cells (RFC) in mice both immune and non-immune to sheep red cells (SRC). RFC formed to endotoxin lipopolysaccharide (LPS) were also Ly-4.2(+). Memory cells to both SRC andLPS could be detected with anti-Ly-4.2 and anti-Thy-1.2 antisera, thereby indicating that both T and B cells are involved in memory to these antigens. Both direct and indirect antibody-forming cells (the PFC) could be inhibited, in vitro, by anti-Ly-4.2 antiserum, although it is likely that not all PFC are Ly-4.2(+). Neither of the specificities Ly-4.2 nor Thy-1.2 were detected on the bone marrow precursor of the splenic colony forming unit (the CFU). In an assay for B cells, the treatment of lymph node or spleen cells with anti-Ly-4.2 before transfer to irradiated recipients could inhibit the ability of these cells to make PFC to SRC, and this capacity could only be restored by bone marrow cells and not by thymus cells. These studies provide clear evidence for the presence of the Ly-4.2 specificity on antibody-forming cells and their precursor (B cells).
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PMID:Ly-4.2: a cell membrane alloantigen of murine B lymphocytes. II. Functional studies. 108 20

Polymerized flagellin and E. coli lipopolysaccharide both express adjuvanticity in vivo and in vitro for responses to hapten conjugated to sheep erythrocytes, and hapten conjugated to soluble thymus-dependent antigens. In the case of erythrocyte-bound hapten, adjuvanticity is expressed in the absence of thymus-derived cells (T cells). However, in the case of responses to soluble thymus-dependent conjugates, carrier-specific T cells would appear to be necessary for adjuvanticity to be expressed. On the basis of these observations an hypothesis for the mechanism of B-cell induction and tolerance is proposed.
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PMID:The inter-relationship of antigenic structure, thymus-independence and adjuvanticity. IV. A general model for B-cell induction. 109 13

Spleen cells from C3H/HeJ mice fail to respond with polyclonal antibody synthesis to mitogenic concentrations of lipopolysaccharide (LPS) which are optimal for activating spleen cells from a high-responder strain (B10.5M). This unresponsiveness is selective for LPS, since C3H/HeJ cells respond as normals to another B-cell mitogen, purified protein derivative of tuberculin. Spleen cells from low-responder mice also fail to mount a specific anti-NNP plaque-forming cell (PFC) response, when challenged in vitro by NNP-LPS. However, C3H/HeJ cells develop normal responses to another thymus-independent hapten conjugate, DNP-AECM-Ficoll. C3H/HeJ mice fail to mount a specific anti-LPS antibody response, when challenged in vivo with doses of soluble LPS which are fully immunogenic for the high-responder strain. However, C3H/HeJ mice develop normal direct and indirect PFC responses to LPS, when challenged with a thymus-dependent form of the immunogen. These results are interpreted as indicating as absolute requirement for functional mitogenicity of the antigen, in the induction of specific thymus-independent antibody responses.
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PMID:Genetical control of B-cell responses. III. Requirement for functional mitogenicity of the antigen in thymus-independent specific responses. 109 88

The immune response at the level of individual immunocytes to the somatic lipopolysaccharide antigen derived from whole Vibrio cholerae and to the purified protein exotoxin from this organism were studied in terms of the role of T- and B-lymphocytes. By adoptive cell transfer studies with irradiated recipient mice, it was shown that normal spleen cells from normal syngeneic mice could readily transfer the capability of responding to both types of cholera antigens. However, when the spleen cells were depleted of T-cells with anti-theta serum and complement, antibody responsiveness to the LPS antigen, but not to exotoxin, could be achieved in recipients. Furthermore, by appropriate transfer of either bone marrow, thymus, or thymus-marrow cell mixtures to irradiated mice, it was shown that the response to the cholera somatic antigen was relatively independent of thymus cells, whereas the response to exotoxin required "helper" T-cells. The role of thymus and bone marrow cells in the intestinal tract in immune responses to the somatic and toxic antigens of cholera vibrios requires further investigation. Further studies should also provide additional information not only concerning the mechanism of the immune response to these antigens in terms of basic mechanisms of antibody formation, but also should provide valuable information in terms of anticholera immunity per se.
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PMID:Involvement of T- and B-lymphocytes in the immune response to the protein exotoxin and the lipopolysaccharide antigens of Vibrio cholerae. 109 72

A thymus-independent immune function in ageing NZB and BALB/c mice was compared by measuring the antibody response to E. coli lipopolysaccharide (LPS). Since it was found that 10-13 month-old NZB mice was particularly sensitive to LPS, this antigen had to be detoxified by alkali treatment. The anti-LPS splenic plaque-forming cell (PFC) response of NZB mice decreases with age and was lower than that of BALB/c mice in all age groups studied. The response of 4- and 10-month-old NZB mice showed an irregular time course and a number of mice showed no response. The present results indicate that, besides an impairment of T-cell functions, an impairment on the B-cell level must also be considered in ageing NZB mice.
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PMID:Age-related decline in the antibody response to E. coli lipopolysaccharide in New Zealand Black mice. 109 67

Normal spleen cells showed a bell-shaped dose response profile when stimulated in vitro with the thymus-independent antigen (4-hydroxy-3,5-dinitrophenyl)acetyl (NNP)-lipopolysaccharide (LPS) with regard to the development of high-avidity plaque-forming cells to NNP. The addition of suboptimal concentrations of LPS to cultures stimulated by suboptimal concentrations of NNP-LPS resulted in optimal induction of B cells in that affinity fraction. Addition of LPS to cultures optimally stimulated by NNP-LPS resulted in paralysis of the specific cells. These results are interpreted in terms of the additive effects between the mitogenicity of LPS and the mitogenicity of NNP-LPS, the latter being selectively focused on the specific cells, thus providing further evidence for the 'one nonspecific signal' hypothesis for immune activation of B cells.
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PMID:Mechanism of B-cell activation and paralysis by thymus-independent antigens. Additive effects between NNP-LPS and LPS in the specific response to the hapten. 109 34

The inheritance of B-cell responsiveness to lipopolysaccharide (LPS) was studied in 55 crosses between mice of the low-responder strain C3H/HeJ and the high-responder strains B10.5M and C3H/Tif. F1 hybrid mice between the low-and the high-responder strains, showed in every case responses which were intermediate between the responses obtained with each parent. The responsiveness among F2 hybrid and backcross mice to either high- or low-responder parents, segregated into intermediate, high, or low categories, respectively. The present results are compatible with the hypothesis that responsiveness to LPS is determined by one single, codominantly expressed, autosomal gene. The capacity to develop a specific thymus-independent response to a hapten-LPS conjugate, also under genetical control, was found to segregate together with the capacity to develop polyclonal responses to LPS.
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PMID:Genetical control of B-cell responses. IV. Inheritance of the unresponsiveness to lipopolysaccharides. 109 75

When spleen cells from mice infected with Rowson-Parr virus (RPV) were cultivated with sheep red blood cells (SRBC), antibody plaque responses were markedly lower than those in similarly cultivated spleen cells from normal mice. Addition of as few as 10(3) spleen cells from RPV-infected mice to cultures of normal aplenocytes markedly depressed the expected immune response. Although RPV-infected mice showed maximum immunodpression in vivo only during the first week after infection, their spleen cells, obtained later in the course of infection, depressed the immunologic responsiveness of normal splenocytes in vitro. Increased doses of SRBC or addition of bacterial lipopolysaccharide to cultures of spleen cells from immunodepressed, RPV-infected mice stimulated antibody formation, and near-normal numbers of antibody-producing cells were evident. Peritoneal exudate (PE) cells, but not thymus, bone marrow, or unfractioned spleen cells, restored immunocompetence to cultures of spleen cells from RPV-infected mice but did not affect the suppressive properties of the infected cells on normal splenocytes. The function of PE cell macrophages in restoring immunocompetence to infected spleen cells in cultures seemed related to a possible antigen-focusing activity of the cells; antibody-producing cell precursors in infected cultures seemed to be preferentially affected by the presence of normal PE cells.
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PMID:Reversal of leukemia virus-induced immunosuppression in vitro by peritoneal macrophages. 110 76


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