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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 BDIX-rats bearing either GVlAl-tumor (a syngeneic mixed glioma) or NVlAc-tumor (a cloned syngeneic neurinoma of the peripheral nervous system) were cytotoxic to both tumor cells in vitro. However, the tumors displayed individually distinct antigenic specificities by in vivo rejection tests. Their in vitro cross-reactivity disappeared when a particular subpopulation of the spleen cells was used. The procedure of lymphocyte purification included three consecutive steps: treatment with carbonyl iron and magnetism, passage through a nylon wool column, and finally removal of complement receptor-bearing cells present in the colum-excluded population. Cross-reactivity between the syngeneic tumors persisted after the first two steps of lymphocyte purification. In contrast, specific cytotoxic reactions were observed against each individual tumor subsequent to the removal of the remaining C3 receptor-positive but surface Ig-negative cells. While killer cells were present in normal spleen-cell populations, these were almost completely eliminated by passage through the nylon wool column.
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PMID:Spleen-cell reactivity against transplanted neurogenic rat tumors induced by ethylnitrosourea: uncovering of tumor specificity after removal of complement-receptor-bearing lymphocytes. 5 Feb 96

We have systematically analysed the various parameters of rat mixed lymphocyte culture (MLC), aiming at defining optimal conditions in analytical (micro) MLC and at the production of maximal numbers of blast cells in preparative (maxi) MLC. Treatment of both responder and stimulator cells, or at least the responder cells, with N-acyl-neuraminidase allowed a good and reproducible analytical MLC response. Responses with a maximal resolution between the stimulated versus nonstimulated control cultures were obtained in the presence of rat sera, BN serum being superior to Lewis and AO serum in supporting the response. Rat sera derived from DA and HO strains, fetal calf serum, and human serum were not good. Spleen cells, lymph node cells, and density-separated blood leucocytes were good responders, and spleen cells were good stimulators, provided the spleen cells were prepurified from most of the phagocytic cells with iron powder plus magnet. Similar culture conditions were applicable also for the maxi-MLC assay. The number of blast cells generated from a single spleen could, however, be increased by a factor of 10, if the responder cell donor was primed intravenously with 10 x 10(6) stimulator-strain spleen cells 72 h before being killed. The responses both in the non-primed and in the primed cultures were specific, since the background stimulation was negligible and the cytotoxic effect by the primed cells in the cell-mediated lysis assay was immunologically specific.
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PMID:Rat mixed lymphocyte culture: optimization of culture conditions. 16 16

Water proton spin lattice relaxation rate (T1) was determined on tissues of rats experiencing early phases of chemical carcinogenesis. Rats were fed a fast acting carcinogen, 3'-methyldimethylaminoazobenzene, and a slower acting carcinogen, 2-acetylaminofluorene, for up to 4 weeks. T1 of blood serum and liver tissue was significantly higher than those of controls after 4 weeks of 3'-methyldimethylaminoazobenzene feeding. This was not the case for 2-acetylaminofluorene. The blood serum T1 increase reflected the onset of liver nodulation (assumed to be preneoplastic). Liver T1 values increased as the degree of nodulation increased. Blood serum T1 correlated inversely with protein content and directly with water content. Liver T1 values correlated with water content, but this was not true for spleen T1 values. Spleen T1 values were significantly lower than controls at the earliest sampling date for each carcinogen: one week for 3'-methyldimethylaminoazobenzene and 4 weeks for 2-acetylaminofluorene. The spleen T1 decrease paralleled an increase of iron detectable by electron spin resonance in this tissue. Spleen T1 decreases are probably not unique to chemical carcinogenesis.
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PMID:Changes of tissue water proton relaxation rates during early phases of chemical carcinogenesis. 16 27

Murine lymphoid cells were infected in vitro with WN 1802 B, a naturally occurring murine leukemia virus isolated from the spleen of an 18-month-old BALB/c mouse. Normal spleen and bone marrow cells were more susceptible to infection than were cells prepared from thymus and lymph node. Spleen cells from athymic nu/nu mice also could be readily infected with virus. Permissive cells did not ingest iron readily infected with virus. Permissive cells did not ingest iron filings and did not adhere to plastic. Exogenous replication of murine leukemia virus was enhanced in spleen and lymph node cells treated with lipopolysaccharide, a bone marrow-derived lymphocyte mitogen. Conversely, cells treated with the thymus-derived lymphocyte cell mitogens, phytohemagglutinin and concanavalin A, were less capable of supporting murine leukemia virus replication. These studies suggest that the natural host for WN 1802 B is the bone marrow-derived lymphocyte.
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PMID:Replication of murine leukemia virus in bone marrow-derived lymphocytes. 18 25

The role of adherent cells in an in vitro secondary response to ectromelia virus infection was investigated. Spleen cells from ectromelia-primed mice ("responder" cells) depleted of adherent cells by either carbonyl iron treatment, adherence to plastic or passage through cotton wool columns had a markedly decreased capacity to produce a secondary response, as indicated by decreased T cell-mediated cytotoxicity against virus-infected target cells, when cultured with virus-infected "stimulator" cells. The secondary response was restored by the addition of peritoneal cells from either normal or ectromelia-immune mice. Small numbers of peritoneal cells completely reconstituted the response within a certain dose range but larger numbers produced a marked inhibition of the response. Spleen cells were less effective in restoring the response. The peritoneal cells were not merely acting as additional, infected "stimulator" or antigen-presenting cells, since they could be added as late as 3 days after culture. Reconstituting activity was not affected by pretreatment with anti-theta serum and complement and cell separation studies showed that the activity was associated mainly with Ig-negative cells and that the active cell probably bears Ia antigens on its surface. These results indicate that the adherent cells involved are probably macrophages and that they act non-specifically to produce optimum conditions for the specific response of T cells.
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PMID:The role of adherent cells in the secondary cell-mediated response in vitro to a natural poxvirus pathogen. 19 60

Spleen cells of C57BL/6J mice bearing a poorly immunogenic syngeneic tumor T241 have been shown to suppress the mitogen-induced proliferative responses of normal spleen cells. However, no suppressive effect of these cells was observed on the generation of cytotoxic cells following immunization in vitro against H-2 histocompatibility antigens. The suppressor activity disappeared rapidly after the removal of the primary tumor. Spleen cells of tumor-bearing mice also suppressed the mitogen-induced stimulation of normal spleen cells of mice of different H-2 loci. Removal of phagocytic cells with carbonyl iron treatment had very little effect on the suppressor activity. Suppressor activity was enhanced following fractionation of cells through nylon wool columns. The suppressor population was found to resist anti-immunoglobulin serum and complement treatment, but treatment with anti-thymocyte serum and complement drastically reduced the suppressor activity. These results indicate that cells with suppressor activity have characteristics of T-lymphocytes.
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PMID:Presence of suppressor cells in spleens of mice bearing a weakly immunogenic syngeneic tumor. 31 43

Spleen cells from mice infected with T. congolense strongly suppressed lymphocyte stimulation induced in normal spleen cells by incubation with mitogens or allogeneic cells. Cell dilution studies showed that suppressor activity was extremely strong. Suppressor cell activity was markedly reduced by treatment of spleen cell populations with mitomycin-C and was unaffected by treatment with anti-Thy.1 sera and complement. Removal of cells which bound carbonyl iron or which bound to nylon columns, decreased but did not abolish suppressor activity.
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PMID:Suppressor cells in Trypanosoma congolense-infected mice. 31 86

Spleen cells from mice immunized with a variety of antigens and incubated in vitro with killed spherules of Coccidioides immitis lyse six to eight times more autologous murine erythrocytes than normal spleen cells and spherules. Cellular and biochemical events in this phenomenon were investigated to ascertain its significance. Kinetic studies suggested that hemolysis results from the activation of some immune cells by spherules. The capacity of spherules to activate these cells is rather unusual because, of the inert particles tested, only zymosan A and crude chitin demonstrated comparable activity. Furthermore, although the hemolytic phenomenon occurred in serum-free medium, more lysis was effected by immune cells and opsonized spherules or zymosan A than by immune cells and untreated fungal particles. Sheep, chicken, and human erythrocytes were not lysed in the hemolytic phenomenon; however, hemoglobin in chicken and sheep erythrocytes was oxidized. Both the murine erythrocyte lysis and oxidation of ovine hemoglobin correlated with the reduction of Nitro Blue Tetrazolium by immune cells adherent to spherules, and both phenomena appeared to be mediated by H2O2 released into the medium by activated cells. Spleen cells reactive with spherules could not be depleted by treatment with iron carbonyl, antiimmunoglobulin plus complement, or anti-brain-associated theta plus complement, but they were partially or completely depleted after rosette formation with erythrocytes coated with antibody or murine complement. Using light and electron microscopy, we noted that immune spleens contained more neutrophils than normal spleens, that these neutrophils reduced Nitro Blue Tetrazolium after stimulation with phorbol myristate acetate, and that they were the most prevalent cell type adherent to spherules after incubation in vitro.
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PMID:Significance of an in vitro phenomenon in which murine erythrocytes are lysed by autologous spleen cells and spherules of Coccidioides immitis. 37 5

The effectiveness of EDTA in reducing the endogenous zinc supply in pregnant rats was determined by two experiments. In experiment 1, a high level of zinc (100 ppm) was given to rats days 15 through 17 of gestation. In experiment 2, a low level of zinc (3 ppm) was given from days 1 through 17. On day 18, half the rats were given EDTA in two intraperitoneal injections 6 hours apart with or without zinc supplementation. The -Zn + EDTA group lost weight continuously after the injections, had increased hematocrit levels prior to parturition,and showed greater stress at parturition than did the -Zn group. Weight gains, hematocrit level, and parturition in the +Zn + EDTA group did not differ significantly from those of the +Zn controls. Spleen weights were decreased in the -Zn + EDTA and -Zn groups and zinc concentration in the spleen increased in the -Zn + EDTA group. Iron concentration decreased in the spleen and increased in the liver of EDTA-treated rats. Use of EDTA to remove endogenous zinc appears to offer a mechanism for study of the effects of short-term zinc supplementation at critical periods in the pregnant zinc-deficient rat.
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PMID:Use of EDTA to produce zinc deficiency in the pregnant rat. 40 59

Spleen cells from chickens 7 days after inoculation with Marek's disease virus (MDV) responded poorly to stimulation by phytohemagglutinin (PHA). Addition of these cells to syngeneic normal spleen cells caused of marked suppression of the PHA response of the normal cells. The MDV spleen cells also inhibited the DNA synthesis of MSB-1 lymphoblastoid cells in vitro. The suppressive activity is attributed to the presence in MDV spleen cells of a population of suppressor cells with characteristics typical of macrophages. The suppressor cell activity was not removable by treatment with anti-T or anti-B serum with C, but it was reversible by treatment with carrageenan or carbonyl iron/magnet, by passage through glass wool column, and by adherence to plastic Petri dishes. The adherent MDV spleen cells also showed strong suppressor cell activity against syngeneic normal spleen cells.
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PMID:Suppression of mitogen-induced proliferation of normal spleen cells by macrophages from chickens inoculated with Marek's disease virus. 65 61


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