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Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spleen cells from mice bearing methylcholanthrene-induced sarcomas or a mammary adenocarcinoma suppressed the mitogen responses of normal spleen and lymph node cells. Lymph node cells from tumor bearers had no suppressive effects. Centrifugation of spleen cells layered on Hypaque-Ficoll (specific gravity of 1.08) produced a dense fraction which pelleted and a light fraction which was retained at the Hypaque-Ficoll-medium interface. Suppressive activity was not found in either fraction of normal spleen cells. In tumor-bearer spleen cells suppressor activity was greatly enriched in the light fraction. Treatment of the suppressor fraction with anti-theta or anti-Ig serum and complement did not remove suppressor activity. However, the suppressor cells were removed by passage through nylon wool or by carbonyl iron treatment. Also, the population which adhered to plastic Petri dishes contained the suppressor cell activity.
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PMID:Suppressor cells in the spleens of tumor-bearing mice: enrichment by centrifugation on hypaque-ficoll and characterization of the suppressor population. 127 Jul 99

Spleen cell suspensions obtained from adult mice were separated by Ficoll/Hypaque and Percoll density gradient centrifugation. The enriched erythroblast populations were maintained in liquid culture medium for 8 hours with 10,000 units of murine interferon (IFN) alpha and beta. Exposure of these cell cultures to murine IFN alpha and beta resulted in a 48% to 70% increase in 2-5adenylate synthetase (2-5AS) activity. In parallel studies, adult mice were injected daily for 1 or 2 weeks with recombinant human IFN alpha A/D (rHuIFN alpha A/D) at a dose of 10(6) or 10(7) units/kg body weight. This treatment did not significantly affect body weight but did produce a mean 70% increase in spleen wet weight and a mean 46% increase in number of nucleated cells per spleen. This increase in number of splenic hematopoietic cells did not result in a corresponding increase in number of circulating cells. In fact, during this 1 to 2 week period the hematocrit dropped from 45% to 38% in mice injected with high dose rHuIFN alpha A/D. From these findings we propose that IFN induces an early 2-5AS activity in erythroblasts and megakaryocytes. This 2-5AS activity, which is known to inhibit protein synthesis in other cell systems, is thought to be responsible for the block or prolongation in blood cell maturation observed in the present studies.
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PMID:Molecular mechanism for the inhibitory action of interferon on hematopoiesis. 273 53

In this study it was examined whether or not antigen specific receptors are on direct and indirect plaque-forming cells (PFC). Spleen cells from mice primed both with horse red blood cells (HRBC) and sheep red blood cells (SRBC) were incubated with HRBC to make rosettes and fractionated on Ficoll-Hypaque density gradient. Both direct and indirect HRBC-PFC were depleted from the interface fraction. The depletion was antigen specific and inhibited by the preincubation of spleen cells with antiserum against kappa- or mu-chain for direct PFC and with antiserum against kappa- or gamma 1-chain for indirect PFC. The depletion was not due to the rosette formation mediated by Fc-receptors which might be on antibody forming cells, because PFC were not eliminated by the density gradient sedimentation after incubation of spleen cells with SRBC coated with anti-SRBC IgG antibody in our experimental conditions. Our results show that the antigen specific immunoglobulin receptors are on the cells producing IgG antibody after primary or secondary immunization as well as on the IgM antibody-forming cells even in late stage of immune response.
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PMID:Antigen specific receptors on murine B cell lineage. 1. On antibody forming cells in various stages of immune response. 616 Feb 70

Spleen cells from unprimed mice or those primed with horse red blood cells (HRBC) were depleted of rosette-forming cells (RFC) with HRBC by the Ficoll-Hypaque density sedimentation, and the cells were examined in the adoptive transfer system whether they could raise IgM or IgG antibody-forming cells (AFC) after an immunization with HRBC. When spleen cells were pooled from unprimed mice, the response to HRBC of those depleted of RFC with HRBC (HRBC-RFC) was decreased to about a half in both IgM and IgG AFC. On the other hand, when spleen cells were from mice primed with HRBC, the response to HRBC of those depleted of HRBC-RFC was decreased dramatically to 1/20 of that of original cells in IgG AFC, but it was decreased to about a half in IgM AFC. In the time course of the response to HRBC of RFC-depleted spleen cells from mice primed with HRBC, an early IgG response was abolished but the late one was as high as that of untreated spleen cells. These results suggest that the depletion of RFC is most effective on the depletion of direct precursors of the secondary IgG AFC.
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PMID:Antigen specific receptors on murine B cell lineage. 2. Different effect of rosette-forming cell depletion on IgM and IgG antibody forming cell precursors in primary and secondary response. 616 Feb 71

The effect of cyclosporin A (CsA) on the production of gamma interferon (IFN gamma) versus IFN alpha/beta was studied using mouse and human lymphocytes and fibroblasts. Spleen cells from C57Bl/6 mice produced low but significant levels (40-60 U/ml) of IFN gamma after 2 to 3 days of culture with irradiated DBA spleen cells. The addition of CsA at concentrations as low as 0.1 microgram/ml completely inhibited (less than 10 U/ml) IFN gamma production in these cultures. High levels of IFN gamma (170-1200 U/ml) were produced when either C57Bl/6 spleen cells or Ficoll-Hypaque-purified human peripheral blood lymphocytes (PBL) were cultured with the T-cell mitogen staphylococcal enterotoxin A (SEA). The addition of CsA (0.1 microgram/ml) to these cultures also completely inhibited (less than 10 U/ml) IFN gamma production. This inhibition was shown not to be due to a change in the kinetics of IFN gamma production or to a change in the amount of SEA required for stimulation. IFN gamma production in SEA-stimulated mouse spleen cells was inhibited at 3 days of culture even when CsA was added at 24 or 48 hr postculture initiation. Thus, CsA inhibits IFN gamma production even when early events associated with lymphocyte activation have been allowed to take place. In contrast to IFN gamma production, IFN alpha/beta production by Newcastle disease virus (NDV)-infected mouse and human lymphocytes or fibroblasts was not inhibited by the addition of CsA (1 microgram/ml). CsA also did not block the action of IFN gamma or IFN alpha/beta since addition of CsA (1 microgram/ml) to reference IFN standards had no effect on their antiviral activity. Thus, CsA inhibits the production of IFN gamma by T cells but appears to have no effect on the production of IFN alpha/beta by virus-infected cells or on the antiviral action of already produced IFN gamma and IFN alpha/beta.
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PMID:Cyclosporin A inhibits the production of gamma interferon (IFN gamma), but does not inhibit production of virus-induced IFN alpha/beta. 640 74