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

Spleen T-cells of mice immunized intravenously with gamma-irradiated allogenic lymphoid cells at a high dose are shown to inhibit the activation of DNA synthesis in MLC. The difference in the whole H-2 complex or in either of its K, I, D regions or I-subregions is required and sufficient for induction of specific T-suppressors. The magnitude of the suppression is a sum of suppressive reactions induced separately by each of the immunizing complex components, the products of one of the H-2 regions (subregions) as shown by changing the source of stimulator cells in MLC. These components have a similar impact in the suppressor activity. Unlike the other T-cell subclasses, T-suppressors react only to serologically defined mutant antigens of the Dd allele, but do not react to the mutants of the Kb allele and do not discriminate Kb and Kba antigens. Specific suppressor T-cells recognize the I-subregion products without their linkage to the K/D region products. For elicitation of the suppression two conditions are required and sufficient: a) direct contact of immune suppressors with the corresponding antigenic determinant; b) the subregion IC identity between the suppressors and the responder cells. Intensity of suppression is reduced if F1 hybrid responder cells interact with parent suppressor cells, but is not reduced in the inverse arrangement of the experiment. Specific suppressor T-cells are presumed to differ from other subclasses of T-cells and to be similar to B-cells relatively to the nature and multiplicity of recognizable individual products of the H-complex and to narrow specialization of reactive clones.
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PMID:[Genetic conditions for the induction and realization of the action of specific T-suppressors immune to H-2 antigens]. 9 36

The effect of Con-A on the generation of cytotoxic lymphocytes (CL) in one way MLC was studied using mouse model. Mitogenic doses of Con-A substantially inhibited primary and secondary CL responses. Spleen cells after in vivo activation by Con-A revealed complete lack of ability to respond in allogeneic MLC. When such cells were added to normal responding cells, even at low proportion, CL generation in primary MLC was also diminished. These observations support the hypothesis that immunosuppressive effect of Con-A is exerted by stimulation of suppressor cells.
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PMID:Immunosuppressive effect of concanavalin-A. I. Suppression of generation of cytotoxic lymphocytes in MLC. 15 33

We analyzed the role of CD4+ and CD8+ T cells in H-2-disparate skin allograft rejection in the mutant mouse strain C.B-17/Icr scid with severe combined immunodeficiency. On the day of skin allografting, scid mice were adoptively transferred with negatively selected CD4+ or CD8+ splenocytes from normal unsensitized C.B-17/Icr mice. These populations were obtained using a double-mAb--plus--complement elimination protocol using anti-CD4 or anti-CD8 mAb that resulted in no detectable CD4+ or CD8+ cells by FACS and negligible numbers of cytolytic T lymphocytes by limiting dilution analysis in anti-CD8 treated populations. Spleen cells were removed from grafted mice at the time of rejection and were tested in vitro for antidonor reactivity in several assays: mixed lymphocyte culture, cell-mediated lympholysis, and LDA for CTL and for IL-2-producing HTL. The presence of Thy 1.2+, CD4+, or CD8+ cells was determined by FACS. All control C.B-17 mice and scid mice adoptively transferred with nondepleted CD4+, and CD8+ cells rejected skin allografts with similar mean survival times (15.6 +/- 1.5, 18.8 +/- 3.4, 18.0 +/- 5.4, respectively), whereas control scid mice retain skin allografts indefinitely (all greater than 100 days). C.B-17 syngeneic grafts survived indefinitely in all groups. At the time of rejection, splenocytes from scid mice receiving CD4+ cells had negligible donor-specific cytotoxicity in CML and negligible numbers of CTL by LDA, but demonstrated a good proliferative response in MLC and IL-2-producing cells by LDA (frequency = 1/1764). There were no detectable CD8+ cells present by FACS analysis. Conversely, splenocytes from scid mice adoptively transferred with CD8+ cells had strong donor-specific cytotoxicity in CML (58.8% +/- 16.1%) and CTL by LDA (frequency = 1/3448), but no significant proliferation was detected in MLC. There were no detectable CD4+ cells by FACS, but there were small numbers of IL-2-producing cells by LDA (frequency = 1/10,204). These data demonstrate that CD4+ cells adoptively transferred into scid mice are capable of mediating skin allograft rejection in the absence of any detectable CD8+ cells or significant functional cytolytic activity. The adoptive transfer of CD8+ cells also results in skin allograft rejection in the absence of detectable CD4+ cells. The detection of small numbers of IL-2 secreting cells in these mice may indicate that CD(8+)-mediated allograft rejection in this model is dependent on IL-2-secreting CD8+ cells.
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PMID:Mediation of skin allograft rejection in scid mice by CD4+ and CD8+ T cells. 135 12

In order to investigate the in vivo functional role of the liver in the immune responses in organ transplantation, effects of perioperative portal venous p.v. administration of donor lymphocytes on renal allograft survival were tested in the rat kidney transplant model. Donor lymphocytes were prepared from BN (BN, RT-1n) or third-party DA (RT1a) rat spleens and lymph nodes and injected p.v. or intravenously to Lewis (LEW, RT-1l) hosts on the day of transplantation (day 0). Untreated LEW hosts rejected BN renal grafts at 7.8 +/- 0.6 days (n = 10). Intravenous administration of 1 x 10(8) BN cells to LEW hosts on day 0 caused a slight, but not significant, prolongation of renal allograft survival (MST = 9.5 +/- 3.0 days, n = 13, NS), whereas portal venous inoculation of 1 x 10(8) BN cells on day 0 remarkably prolonged renal graft survival to 22.2 +/- 5.3 (n = 10, P less than 0.01). The prolongation of graft survival was antigen-specific; the administration of 1 x 10(8) DA cells p.v. to LEW hosts did not prolong the survival of BN renal grafts (MST = 7.4 +/- 0.8, n = 5). Spleen cells from p.v. treated LEW hosts 10 days after transplantation had no suppressor effect on the one-way MLC reaction of normal LEW responder cells toward donor BN or third-party DA stimulators. On the other hand, when serum from p.v.-treated LEW hosts was added to MLC at a concentration of 3 per cent of total volume, it suppressed the MLC reaction toward donor BN cells by 71.6 per cent, but not toward third-party DA stimulators (-8.5 per cent suppression, NS). Histological examination of p.v.-treated LEW hosts at 10 days after transplantation revealed that the liver had normal lobular architecture without expansion of portal tracts and infiltration of inflammatory cells. On the other hand, the transplanted kidney demonstrated a moderate mononuclear cell infiltration around the artery without an interstitial hemorrhage. Moreover, adoptive transfer of the serum from p.v.-treated LEW rats into the virgin secondary LEW hosts significantly prolonged the graft survival of BN kidneys from 7.8 days to 18.9 +/- 5.5 days (P less than 0.01), but not third-party DA graft survivals (MST = 7.5 +/- 0.6 days), indicating that an antigen-specific tolerogenic factor was released into the circulation through the process of allogeneic cells in the liver.
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PMID:The effects of perioperative portal venous inoculation with donor lymphocytes on renal allograft survival in the rat. I. Specific prolongation of donor grafts and suppressor factor in the serum. 230 Oct 7

The aim of the study was the prolongation of heart allograft survival in rats after DST (donor specific blood transfusion), the characterization of T and B lymphocyte phenotypes in peripheral blood, spleen and lymph nodes and the evaluation of specific and nonspecific suppressor cell activity of spleen and blood lymphocytes of DST rats. Pretreatment of Wistar recipients with one, two and three doses of DST-s prolonged the heterotopic August graft survival to 11.0, 12.3 and 11.4 days, respectively (rats differed across the MHC). Spleen lymphocytes of transfused rats showed significant nonspecific suppressive activity in culture with syngeneic spleen lymphocytes of nontransfused rats stimulated with PHA, but not in culture with blood lymphocytes. Blood lymphocytes of transfused rats did not show any nonspecific suppressive activity. Spleen and blood lymphocytes of transfused rats did not demonstrate any specific suppressive activity in allogeneic MLC. The ratio of W3/25+/OX8+ (Th+/Tsup/cyt+) cells in peripheral blood was found increased in DST rats due to the decrease in the percentage of OX8+ cells whereas the opposite effect was observed with spleen cells (increase in the percentage of OX8+ cells after one DST). The number of OX6+ (Ia positive) cells and B cells in all transfused rats was found unchanged comparing with untreated animals.
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PMID:Prolongation of heart graft survival and spleen suppressor cell activity after donor specific blood transfusions in rats differing across the MHC. 253 86

Spleen cells from mice treated with LS2616 display a highly increased response to the polyclonal T cell lectin ConA. The total number of splenic T cells, and the relative ratios between L3T4+ and Lyt-2+ T cells were not altered by LS2616 treatment. By dissecting the overall ConA response it was found that the number of ConA-inducible, IL-2 reactive T cells was unaffected, while ConA-induced IL-2 production was enhanced after LS2616 treatment. Spleen cells from LS2616 treated mice, depleted of G10 adherent macrophages (M phi) and reconstituted with M phi from untreated mice displayed normal levels of ConA responses. M phi depleted spleen cells from untreated animals, cocultured with M phi enriched populations from LS2616 treated animals resulted in an increased ConA response. Furthermore, spleen cells from treated mice were found to be excellent stimulators for alloantigen-induced T cell responses; when used as responders in MLC, however, these cells were comparable to responders from non-treated animals. Taken together the results demonstrate that LS2616 exerts an immunostimulatory effect on M phi, which indirectly facilitates polyclonal and antigen-specific T cell responses. The possible implications of this observation on various immunoregulatory events are discussed.
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PMID:Mechanism of action of the new immunomodulator LS2616 on T cell responses. 295 30

We studied the effect of blood transfusions (BT) from different H-2 donors on the induction of suppressor cells (SC) and of MLC inhibitory activity in serum in a drug-unmodified mouse model. Balb/c (H-2d) mice were transfused at weekly intervals with whole blood from donors of three strains using two transfusion protocols. In protocol I, blood was transfused first from C3H/HeJ (C3H) (H-2k), then C57Bl (H-2b), and then SJL (H-2s) strain mice, and in protocol II the order of blood donors was reversed. Spleen cells and serum samples were obtained from the transfused mice one and two weeks after the last BT. In both transfusion protocols, the kinetics of responses of cells from recipient transfused mice to cells from the blood donors in MLC were similar to those of cells from nontransfused mice. The peak responses of cells from transfused mice were consistently lower than those of cells from nontransfused mice. In cell-mixing experiments, radiosensitive SC capable of inhibiting responses of Balb/c mice to cells from all three blood donors in MLC could be demonstrated one week after the last transfusion in both protocols. Two weeks after the last BT, SC were demonstrable only against the first (C3H) blood donor in protocol I, and against all three blood donors in protocol II. Serum obtained one week after transfusion in protocol I inhibited responses of Balb/c mice to stimulator lymphocytes from all three blood donors in MLC. Serum obtained two weeks after BT, however, inhibited responses of recipient mice only to the first blood donor. In contrast, in protocol II, serum obtained both one and two weeks after BT did not cause inhibition of responses of cells from Balb/c mice to blood donor cells in MLC. Similar results were obtained when Balb/c mice were transfused at weekly intervals with whole blood from either C3H or from SJL mice. The data suggest that the induction of SC and/or MLC-inhibitory activity in the serum after BT is dependent on the H-2 type of the first blood donor.
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PMID:Effect of blood transfusions from different H-2 donors on immune responses in mice. 296 36

Spleen cells from Mice infected with N. brasiliensis produce a large amount of histamine in response to adult worm antigenic extract, to con A, or during primary MLC. During worm antigenic or con A response, this phenomenon results from an increase in HCSF production and HCSF sensitivity. During primary MLC, only an increase in HCSF sensitivity is observed without increase in HCSF production. This increase in histamine and HCSF production is correlated with the "self-cure" phenomenon.
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PMID:[Production of histamine induced by a lymphokine during infection with Nippostrongylus brasiliensis]. 618 48

In response to T cell mitogens, spleen cells produce a large amount of histamine, whereas no or a slight increase is observed after B cell mitogen stimulation. This increased histamine production results from the effect of a factor having all the characteristics of HCSF (histamine-producing cell-stimulating factor) already described in secondary MLC supernatant. This factor is produced by Thy-1, 2, Lyt-1, 2-positive cells. Spleen cell cultures derived from skin-allografted mice during rejection produce more histamine in response to T cell mitogens than do spleen cells from normal or syngeneic grafted mice. Such a phenomenon is not observed in response to B cell mitogens. A striking association is found between enhanced histamine synthesis and skin allograft rejection. This phenomenon results from a) a five to 10-fold increase in HCSF production by allograft recipient spleen cells in response to T cell mitogens, and b) an increase in HCSF sensitivity of these spleen cells.
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PMID:Skin allografts generate an enhanced production of histamine and histamine-producing cell-stimulating factor (HCSF) by spleen cells in response to T cell mitogens. 618 52

A model for bone marrow transplantation across minor histocompatibility barriers was developed by using mouse strains that were H-2 identical and mutually non-reactive in MLC. Acute graft-vs-host disease was induced only when donor lymphoid cells were included in the marrow inoculum, in both C57BL/6 recipients of LP cells and BALB/c recipients of B10.D2/nSN cells. GVHD was prevented by treating the lymphoid cells with anti-Thy 1.2 and C before transplantation. Spleen cells from mice with acute GVHD were not directly cytotoxic to recipient strain target cells. However, when spleen cells from mice with GVHD were boosted in vitro to recipient strain stimulator cells they generated a specific anti-recipient cytotoxic response. Spleen cells from mice without GVHD did not generate a cytotoxic response in vitro. The cytotoxic effector cells and their precursors were shown to be T lymphocytes. This model and the in vitro method described may be useful in further studies of the immunobiology of GVHD due to minor histocompatibility antigens and of transplantation tolerance.
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PMID:Anti-recipient cytotoxic T lymphocyte precursors are present in the spleens of mice with acute graft versus host disease due to minor histocompatibility antigens. 645 Feb 46


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