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

The late effects of various immunosuppressive insults on cell-mediated immunity in mice were studied in an attempt to assess the role of immune surveillance in the aging process. Results were obtained using susceptibility to allogeneic tumor cell challenge, graft-versus-host reaction (GVHR), blastogenic response to PHA, a thymus derived T cell-specific plant mitogen, and cytolytic activity against allogeneic tumor cells as measures of immunologic activity. In vivo studies late in life show that resistance to allogeneic tumor cells is significantly decreased in thymectomized mice, whereas those treated with cortisone, cyclophosphamide and sublethal X-ray remain unchanged. Spleen cells from only the thymectomized and the sublethally irradiated mice show reduced activity in the GVHR. No difference is seen in the activity of bone marrow cells. Results consistent with these findings were obtained in in vitro studies. Thus spleen cells from thymectomized or sublethally irradiated mice show decreased activity is response to PHA, whereas no change is seen in spleen cells from other treated groups. Hence, surgical and physical insults are more likely to induce long-lasting immunosuppression in those immunocompetent tissues whose activity normally diminishes with advancing age. Furthermore, the degree of immunosuppression seen in this study is not of the order of magnitude that one could reasonably predict a significant decrease in mean life-span.
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PMID:The late effects of selected immunosuppressants on immunocompetence, disease incidence, and mean life-span. II. Cell-mediated immune activity. 0 May 62

Replication of HSV was demonstrated in spleen cell cultures of D2 and several other strains of mice after prestimulation with mitogenic doses of LPS for 2 days. No viral replication occurred in unstimulated cultures or in cultures prestimulated with PHA and Con A, whereas there was some viral replication in spleen cell cultures of D2 mice after prestimulation with Poly I-C. Spleen cells of B6 mice did not support replication of HSV under any of the conditions we have tested thus far. The reasons for this defect are not clear, but it was obviously not caused by a defective lymphoproliferative response to LPS or by an active anti-viral principle elaborated by B6 spleen cells. F1 hybrids between B6 and D2 mice were capable of HSV replication to the same extent as were spleen cells of D2 mice. Several strains of both HSV-1 and HSV-2 could be replicated in D2 spleen cells cultures. Nylon column treatment of D2 spleen cells removed the ability to replicate HSV, whereas macrophage removal from the spleens by plastic adherence was without effect. Purified peritoneal exudate cells from D2 mice did not support replication of HSV. Together these data suggest that B cells activated by LPS represent the target cell of HSV replication in mouse spleen cell cultures.
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PMID:Replication of herpes simplex virus in mouse spleen cell cultures stimulated by lipopolysaccharide. 18 34

Mice exposed to a sublethal dose of X-rays were immunized with alum-precipitated DNP-KLH (dinitrophenyl-keyhole limpet haemocyanin) and B. pertussis either before or after irradiation. The primary anti-DNP antibody response was evaluated during 8 weeks after immunization by the equilibrium dialysis technique using ammonium sulphate- precipitated serum globulins and the ligand 3H-labelled xi-DNP-L-Lysine. The serum concentrations of antibody sites in mice immunized 1-5 days before or 2 h-8 weeks after 450 rad were below the values in unirradiated controls at all bleeding times. Antibody affinity, however, was found to be up to 20 fold higher in irradiated mice than in control mice when antigen was injected before, or 3-8 weeks after, irradiation. Spleen cells from mice exposed to 450 rad 1-9 weeks before killing were stimulated in vitro with PHA, ConA, or LPS. Recovery profiles of mitotic responsiveness suggest that enhancement of antibody affinity in irradiated mice could result from relative lack of suppressor T Cells.
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PMID:Effects of whole-body irradiation on antibody affinity. 19 58

Spleen cell populations from mice treated with Adriamycin or daunorubicin were found to develop a greater PHA-stimulated clonal response than spleen cells from untreated or cyclophosphamide-treated animals. Daunorubicin, in addition, stimulated an unusual monocytic macrophage-like colony. The results are consistent with the possibility that the concentration of nonspecific T-lymphocyte progenitor and/or accessory cells in the spleen are increased consequent to drug treatment.
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PMID:Increased development of PHA-stimulated murine colonies in vitro subsequent to adriamycin or daunorubicin treatment of spleen donor mice. 31 67

The immune competency of nude mice born from matings of strictly homozygous nu/nu X nu/nu parents was compared to nude mice derived from the breeding of either heterozygous nu/+ mothers by nu/nu fathers or nu/nu mothers by nu/+ fathers. Spleen cells from nude mice born from heterozygous mothers had significantly higher levels of beta-bearing cells than mice born from homozygous mothers and were minimally stimulated by the T cell mitogens Con A and PHA-P. In contrast, there were no detectable maternal influences when survival of skin allografts and primary sheep red cell stimulation were studied. Homing studies of 51Cr thymocytes in term-pregnant nude mice suggest that the enhanced T cell characteristics of nude mice born of nu/+ mothers are caused in part by placental transfer of allogeneic maternal lymphocytes.
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PMID:Immune competency of nude mice bred from homozygous and heterozygous mothers. 79 7

Spleen cells from mice inoculated with partially purified preparations of interferon (Sp. Act. 1 X 10(7) i.u./mg protein, 0.2 ml i. v./mouse) were stimulated in vitro with phytohemagglutinin, concanavalin A or lipopolysaccharide. After 2 days of stimulation, the incorporation of 3H-thymidine into TCA-insoluble radioactivity was inhibited 50-90% when compared with cells from animals inoculated with mock interferon. Maximal inhibition, with optimal doses of lectins was obtained when interferon was;inoculated 18 hours before. This effect of interferon on DNA synthesis was preceeded by inhibition of the incorporation of 3H-uridine into TCA-insoluble material. When cells were pretreated in vitro with interferon for 24 hours and subsequently stimulated with PHA, RNA synthesis was inhibited by 30-40%, whatever was the dose of the mitogen. The synthesis of 4S tRNA, 18S and 28S ribosomal RNAs were inhibited to the same degree by interferon. The incorporation of methyl groups into cytoplasmic sRNA was unaltered.
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PMID:Inhibitory effect of interferon on DNA and RNA synthesis in murine spleen cells stimulated by lectins. 93 1

Mouse lymphocyte populations exposed to mitogen were tested for their capacity to release factors that stimulate other lymphocytes to synthesize DNA or enhance their response to mitogens in vitro. The target lymphocyte for this mitogenic factor(s) (MF) was also characterized. The results showed that lymph node and spleen cells release more MF than thymocytes upon exposure to Con A, PHA or PWM in vitro. The T cells were found to be largely responsible for MF production, since cell suspensions depleted of phagocytic cells did not exhibit any decreased ability to produce MF and spleen cells from congenitally athymic (nude) mice produced no detectable MF activity. The MF stimulated thymocytes, lymph node cells, and spleen cells to synthesize DNA. Spleen cells from nude mice were also stimulated. The MF released by lymphocytes in response to Con A was found to induce DNA synthesis of lymphocytes in itself and did not require the presence of mitogen. It is concluded that phytomitogen lectins stimulate T cells to synthesize DNA and to release soluble factor(s) which are mitogenic for both T and B cells. The latter cells may thus be unresponsive to the phytomitogen, but still undergo blast transformation.
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PMID:Characterization of mouse cells releasing or responding to mitogenic factor induced by phytomitogens in vitro. 107 42

T-lymphocytes differ antigenically from B-lymphocytes. In the present study attempts were made to determine the role of surface antigens of T-cells, in their migration in vivo and in their response to mitogens. Exposure of thymus cells to anti-H2 sera inhibits migration to the lymph nodes (LN) to a greater extent than to the spleen. Fab fragments of H-2 antisera had only a slight effect on lymphocyte migration, inhibiting the LN-seeking stream only slightly more than the spleen-seeking stream. The interaction of Con-A with carbohydrates on the cell-surface of lymphocytes inhibits preferentially their localization in LN. Studies on the migration of lymphocytes that had localized either in the LN or spleens of primary host indicate that Con-A does not eliminate LN-seeking cells, but rather inhibits their active localization in LN. The subpopulation of lymphocytes, in both thymus and spleen that responds to Con-A was found to possess a higher H-2 antigenicity and a lower Ly and theta-antigenicity than the cells responding to PHA. Spleen cells responding to low concentrations of PHA had a relatively high H-2 antigenicity, whereas thos responding to high concentrations of PHA had a low H-2 antigenicity. Exposure of thymus cells to H-2 antiserum alone markedly inhibited their response to Con-A. Similar treatment of spleen cells had only a weak inhibitory effect.
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PMID:The nature and function of T-cell antigens. 109 75

Spleen cells from C57BL/6N mice injected with killed Corynebacterium parvum (CP) had a marked growth inhibitory effect on the in vitro proliferation of RBL-5 murine lymphoma cells. It was most marked 12 to 14 days after injection and was usually no longer detectable later than 21 days. It could be demonstrated at effector cell to target ratios between 20:1 and 5:1 at which normal spleen cells had a growth-promoting effect. Addition of CP to an in vitro mixture of spleen cells and tumor cells augmented the inhibitory effect of spleen cells from CP-injected mice although it conferred no inhibitory potential on normal spleen cells. Growth inhibiton by CP spleen cells was not mediated by T cells and various depletion experiments suggested that the effector cells of the phenomenon were macrophages. Spleen cells of CP-injected mice also showed strongly depressed responses to the T cell mitogens PHA and Con A and suppressed the mitogen responses of syngeneic normal spleen cells. The characteristics of the suppressor cells mediating this effect appeared to be very similar to those inhibiting lymphoma cell growth. The responses to LPS were also strongly suppressed in mice injected with 2.1 mg of CP. However, after injection of one-tenth of the dose a relative sparing of the LPS response was noted, whereas the PHA response was still suppressed.
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PMID:Splenic suppressor macrophages induced in mice by injection of Corynebacterium parvum. 117 73

The in vitro production of histamine releasing factor (HRF) by lymphoid cells of rats, both normal and infected with Nippostrongylus brasiliensis, has been studied. Spleen cells and thymocytes were cultured either alone or in the presence of mitogen (PHA, 10 and 50 micrograms/ml) and the dialysed cell-free supernatants were tested for histamine releasing activity on rat peritoneal and pleural mast cell in vitro. We found that spleen cells and thymocytes of normal rats stimulated with PHA in 24 h cultures generated a factor which released histamine and 5-hydroxytryptamine from mast cells, and this ability was potentiated following N. brasiliensis infection of rats - lymphoid cells donors. Pleural mast cells were more sensitive to the action of HRF than peritoneal cells. Rat HRF had an apparent m.w. of 50,000 to 70,000 daltons as determined by gel chromatography and was a heat stable protein inducing histamine release from homologous mast cells in a very rapid (complete in 1-2 min at 37 degrees C), dose and temperature dependent secretory process.
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PMID:Rat lymphoid cell--derived histamine and 5-hydroxytryptamine releasing factor. 128 Apr 98


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