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)

An animal model of a sublethal infection, utilizing murine cytomegalovirus (MCMV), was developed to determine whether immunological factors could contribute to the establishment of a persistent viral infection. Adult female C3H mice inoculated intraperitoneally with 10(5) plaque-forming units of MCMV developed splenomegaly 5 to 12 days after infection. Virus replicated to peak titers (10(3) to 10(6) plaque-forming units per g of tissue) in liver, spleen, lung, kidney, and salivary gland tissue during the acute phase of the infection (3 to 12 days); it then decreased to undetectable levels in all tissues except salivary gland. Serum interferon was detected as early as 12 h after infection, peaked at 36 h (1,093 U/ml), and was undetectable by 4 days after infection. MCMV-infected animals were hyporeactive to interferon induction with New castle disease virus on days 5 to 9 of the infection. Splenic lymphocyte reactivity to phytohemagglutinin and lipopolysaccharide was normal early during the course of the infection, was suppressed during the acute phase of the infection, and had returned to normal by day 18. These data indicate that several parameters of host defense are transiently suppressed during the course of a MCMV infection. The capacity of cytomegaloviruses to alter host resistance may be one factor that contributes to the establishment of a persistent infection.
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PMID:Alteration of host defense mechanisms by murine cytomegalovirus infection. 20 66

A consistent modification in B lymphocyte activation has been observed 1 month after infection of C3H/HeJ mice with scrapie. The mitogenic response to lipopolysaccharide of splenocyte cultures from experimental mice was reduced 30 to 60% as compared to controls. This reduction in mitogen responsiveness was transient but coincided with the onset of detectable splenomegaly and with the reported recovery of maximum yield of infectious scrapie agent in the spleen. The DNA synthetic response to lipopolysaccharide stimulation of splenocytes from scrapie-infected C3H/HeJ mice was depressed relative to controls only between 20 and 40 days after intracerebral inoculation. At all other times, experimental and control responses were identical. Scrapie-associated decreases in mitogenesis were found whether the spleen cell cultures contained splenocytes from individual mice, splenocytes pooled from several mice, or gradient-purified mononuclear cells. The responses of C3H/HeJ splenocyte cultures to phytohemagglutinin or concanavalin A stimulation were unaffected by scrapie infection.
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PMID:Suppression of polyclonal B cell activation in scrapie-infected C3H/HeJ mice. 30 27

The effect of a Brucella abortus preparation (Bru Pel) on the T- and B-lymphocyte populations is described. Bru Pel treatment of tumor-bearing mice resulted in a slight reduction in tumor size, marked splenomegaly, and statistically significant reductions in the percentages of splenic T and B lymphocytes relative to untreated tumor controls. Bru Pel was also found to cause increases in the incorporation of 3H-thymidine of phytohemagglutinin-sensitive splenic T lymphocytes and lipopolysaccharide-sensitive splenic B lymphocytes over 3H-thymidine-incorporated values for untreated tumor controls.
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PMID:Lymhocyte stimulatory effect of an ether-extracted preparation of Brucella abortus. 31 Mar 45

Peripheral lymphocytes responsive to stimulation by phytohaemagglutinin (PHA) and bacterial lipopolysaccharide (LPS) in culture have been quantitated following treatment of mice with anti-thymocyte serum (ATS), total body irradiation or corticosteroids. The ATS reduced the number of PHA-responsive cells in both blood and spleen, and induced splenomegaly, but it had little deleterious effect on spleen-borne LPS-responsive cells. In contrast, the spleens of mice treated with hydrocortisone acetate were atrophied and the remaining cells had a reduced LPS response and an enhanced PHA response. Total body irradiation impaired both PHA and LPS responsiveness in the spleen. Recovery of PHA responsiveness after either irradiation or ATS treatment was prolonged and was dependent on the presence of an intact thymus; recovery of LPS responsiveness after corticosteroid treatment was more rapid and was thymus-independent.
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PMID:Effects of irradiation, anti-thymocyte serum and corticosteroids on PHA and LPS responsive cells of the mouse. 32 22

Spleen weights and mitogen responsiveness of splenocyte cultures from scrapie agent-infected and control-inoculated mice were compared over two-month periods following inoculation. Splenocytes from Swiss, C57B1, and BALB/c mice were stimulated with the T (thymus-derived) cell mitogens phytohemagglutinin or concanavalin A, the B (bone marrow-derived) cell mitogen bacterial lipopolysaccharide, or pokeweed mitogen, a stimulator of both T and B cells. Although significant splenomegaly was associated with scrapie infection, we failed to observe any significant differences in the activation of experimental and control cells. Studies with BALB/c mice suggested the possibility, however, that with both phytohemagglutinin and lipopolysaccharide, specific decreases in lymphocyte activation might occur with more optimal culture conditions. The data are consistent with the idea that the scrapie agent stimulates only subtle immunological changes within the host as it destroys the cells of the central nervous system.
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PMID:Mitogen stimulation of splenocytes from mice infected with scrapie agent. 56 56

The injection of a single sublethal dose of cyclophosphamide (CY) into adult C3H/He mice induced splenic atrophy followed by considerable hypertrophy. During the phase of splenomegaly, the in vitro reactivity of spleen cells to the mitogens phytohaemagglutin and lipopolysaccharide was drastically decreased. Furthermore, the spleen cell population from CY-treated mice contained suppressor cells capable of inhibiting the in vitro reactivity of normal lymphocytes to these mitogens. After the removal of adherent cells, the suppressive activity was completely absent from the remaining fraction. The suppressive activity was also abolished after treatment of spleen cells with anti-immunoglobulin antiserum plus complement (C). After treatment with anti-Thy 1-2 antiserum plus C, the suppressive activity was not modified. Nude mice, B mice, young and old NZB mice, also developed suppressor cells with similar functional characteristics when treated with CY. However, in Nude mice the suppressor cells were not adherent and did not bear surface Ig. After fractionation of spleen cells by velocity sedimentation, the suppressive activity was detected in the fastest fraction with a velocity over 5 mm/h.
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PMID:Induction of suppressor cells in mice by cyclophosphamide. 69 15

The receptor for gp70 envelope glycoprotein of murine ecotropic leukemia virus is essential for virus entry into the host cell and has been recently demonstrated to function as a cationic amino acid transporter. In the experiments reported herein, we compared the gene expression of the murine ecotropic retroviral receptor (ERR) and its human homolog (H13) in rapidly proliferating cells versus resting cells using four different systems. (i) The expression of ERR gene is enhanced during activation of T and B lymphocytes by concanavalin A and lipopolysaccharide, respectively. Similar enhancement is observed by adding phorbol 12-myristate 13-acetate (PMA) or calcium ionophore (A23187). These phenomena appear to involve protein kinase C; two PMA analogs, 4 alpha-phorbol and 4 alpha-PMA, lacking the ability to activate protein kinase C fail to induce elevated levels of gene expression, and the protein kinase C inhibitor, H7 [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine dihydrochloride[, inhibits the enhancement induced by PMA. (ii) Friend murine leukemia virus induces rapid splenomegaly, and acute erythroleukemia in sensitive mice. Concomitantly with splenomegaly, ERR gene expression in spleen cells increases dramatically. (iii) The level of expression of the ERR or H13 gene in a variety of tumor cells is highly elevated compared with the level in noncancerous cells. (iv) H13 gene expression decreases upon terminal differentiation of the human promyelocytic leukemia cell line HL-60 into granulocytes or macrophages by dimethyl sulfoxide or PMA, respectively. These results suggest that ERR and H13 genes play an important role in cellular proliferation.
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PMID:Enhanced gene expression of the murine ecotropic retroviral receptor and its human homolog in proliferating cells. 131 7

Corynebacterium xerosis cell-wall fractions were studied by electron microscopy and analysed for immunomodulating activity. Dramatic splenomegaly occurred following the injection of whole cells or a purified cell-wall fraction (PF), but not with a further purified peptidoglycan (PEP) fraction. Both PF and PEP acted as B-cell mitogens and had adjuvant capabilities comparable to commercial adjuvants. Only the PF fraction enhanced peritoneal natural killer cell (NK) activity, paralleling the splenomegaly response. When spleens from mice injected with PF or PEP were analysed for their abilities to respond to mitogens and for the presence of suppressor cells, reduced mitogenic responses occurred only in PF-injected mice during the peak of splenomegaly. Spleens from both PF- and PEP-injected mice contained suppressor cell activity which peaked 2 weeks post-injection. This activity was primarily directed at B-cell responses to lipopolysaccharide (LPS). C. xerosis cell-wall fractions thus offer great potential as a new immunomodulator.
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PMID:Immunomodulating activities of Corynebacterium xerosis cell-wall fractions. 140 38

Inheritance of the Ityr or the Itys allele of the Ity murine gene confers resistance or increased susceptibility, respectively, to Salmonella typhimurium infection. Recent studies have documented that Ity gene expression may determine net intracellular replication of S. typhimurium by modulating macrophage function. The purpose of this study was to determine if Ity gene expression modulated macrophage stem cell proliferation as well. To detect possible Ity-associated alterations in macrophage stem cell proliferation during endotoxin challenge or S. typhimurium infection, the congenic strain pair BALB/c (Itys) and C.D2-Idh-1, Pep-3 N20F8 (Ityr) were injected intraperitoneally with 25 micrograms of bacterial lipopolysaccharide (LPS) or approximately 10(3) S. typhimurium, and myelopoiesis was evaluated. At 72 h after LPS injection, both BALB/c and C.D2 mice developed comparable degrees of bone marrow hypocellularity and splenomegaly, and cell sizing profiles indicated a normal response to a single injection of LPS in both strains of mice. Although an inhibitor to colony-stimulating factor activity was detected in the sera and plasma of C.D2 mice, the number of myeloid stem cells cultured from the bone marrow and spleen of each mouse strain were comparable. S. typhimurium infection resulted in earlier symptoms, a larger bacterial load, a higher mortality rate, and a greater bone marrow hypocellularity and splenomegaly in BALB/c mice compared with those in C.D2 mice. Despite a dramatic increase in bacterial load, a decrease in both bone marrow and splenic myeloid stem cell numbers was noted in BALB/c mice, while stem cell numbers remained constant in C.D2 mice between days 3 and 5 and increased dramatically at day 7 after infection. These data suggest that BALB/c and C.D2 mice may exhibit a divergent myelopoietic response to S. typhimurium infection. It appears that a paradoxical failure of myelopoiesis in Itys mice during S. typhimurium infection may contribute to the observed increase in mortality.
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PMID:Differential myelopoietic responsiveness of BALB/c (Itys) and C.D2 (Ityr) mice to lipopolysaccharide administration and Salmonella typhimurium infection. 154 63

A live, avirulent strain of Salmonella typhimurium, SL3235, was previously shown to afford protection against virulent Salmonella challenge in three mouse strains of the C3H lineage, C3H/HeJ, C3HeB/FeJ, and C3H/HeNCrlBR, which differ in their innate susceptibility to Salmonella infection, as well as in their responsiveness to lipopolysaccharide (LPS). Concurrent with protection, however, SL3235 was found to induce greater than 90% reduction in proliferative responses of splenocytes from immunized mice to a panel of B and T cell mitogens. Suppression appeared to be independent of susceptibility to Salmonella infection, since the mitogenic responses of hypersusceptible C3H/HeJ and C3HeB/FeJ, as well as resistant C3H/HeNCrlBR mice, were suppressed. The suppressor cell population in immunized C3HeB/FeJ mice was recently shown to be of monocytic lineage. Using transwell plates, co-culture studies indicated that suppression was mediated by soluble factors. In the present study, the effect of LPS responsiveness on susceptibility to SL3235-induced suppression was evaluated in C3H mice by studying their ability to mount plaque-forming cell (PFC) responses to sheep red blood cells (SRBC) and in vivo antibody responses to tetanus toxoid. Comparison of PFC responses as a function of SL3235 dose in C3HeB/FeJ and C3H/HeJ mice, revealed that the latter strain was markedly more resistant to the development of suppression, as evidenced by the significantly higher (10-35-fold) SL3235 doses needed to achieve comparable suppression to those seen in C3HeB/FeJ mice. In contrast to C3HeB/FeJ mice, suppression in C3H/HeJ mice required direct cell-cell contact. In both mouse strains, suppression was alleviated by pre-treatment of immune splenocytes with either mitomycin C or x-irradiation, indicating that actively proliferating cells are required for suppressor function. Resistance of C3H/HeJ mice to SL3235-induced suppression was not due to a lesser bacterial load in vivo, since a higher number of SL3235 organisms were seen in C3H/HeJ spleens compared to C3HeB/FeJ mice. Rather, resistance of C3H/HeJ mice correlated with their reduced ability to recruit macrophages and other inflammatory cells into the spleen, as evidenced by the significantly smaller degree of splenomegaly induced in these mice following immunization with SL3235.
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PMID:Immunosuppression induced by attenuated Salmonella: effect of LPS responsiveness on development of suppression. 163 Feb 97


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