Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies were designed to prospectively evaluate the effects of selective depletion for donor T cells strongly expressing the CD3 and CD5 pan-T antigens on the incidence of leukemia relapse following bone marrow transplantation. This evaluation was performed under controlled conditions in a mouse model for MHC-matched unrelated-donor transplantation, employing Rauscher leukemic SJL/J mice as the recipients and leukemia-resistant B10.S mice as the donors. Selective donor cell depletion for CD3 and CD5 was accomplished ex vivo prior to transplantation by incubation with the appropriate monoclonal antibody plus complement. When untreated, Rauscher leukemia resulted in a 97% fatality incidence. This was reduced to 30% by the transplant of non-depleted B10.S cells, with another 37% recipients dying from GVHD and graft failure. CD3 depletion reduced the GVHd deaths to 6% but increased relapse to 62%. Conversely, CD5 depletion had no effect on relapse or on GVHD but did significantly increase graft failure, thus negatively affecting survival. Evaluation of the results, done in conjunction with flow cytometry analysis of the effects of CD3 versus CD5 depletion on the donor cells, suggests that the T cells involved in suppressing leukemic relapse in these studies, and hence contributing to the GVL response, most probably had a phenotype of CD3+, CD5-.
 ...
PMID:Comparison of the effects of CD3 and CD5 donor T cell depletion on graft-versus-leukemia in a murine model for MHC-matched unrelated-donor transplantation. 751 54

We previously reported that Mls-1a B10.D2 donor preimmunization prevents the development of a lethal graft-versus-host disease (GVHD) directed against host minor histocompatibility antigens (mHAgs) in lethally irradiated (DBA/2 x B10.D2)F1 recipients (LS mice). In the same combination, the graft of T-depleted bone marrow cells also results in no GVHD (TCD BM mice). Both groups of mice exhibit a host specific tolerance. In this paper, we examined whether a graft-versus-leukemia (GVL) effect can still take place without lethal GVHD in LS and TCD BM mice. The i.v. injection of P815 tumor cells into these mice, 2-3 months after the graft, indicates an antitumor activity in LS mice but not in TCD BM mice. When the P815 cells were administered 1 day before irradiation and graft, the leukemic mortality was significantly delayed in mice reconstituted with BM and spleen cells from a preimmunized donor, but not in mice reconstituted with T cell-depleted BM. In LS mice, a subclinical GVHD develops, probably due to CTL alloreactivity against host mHAgs that is observed in vitro. Moreover, cell depletion of the donor inoculum before grafting indicates that the antitumor effect is exclusively mediated by CD8+ T cells. In summary, a beneficial GVL effect, mediated by CD8+ T cells, can be preserved without lethal GVHD.
 ...
PMID:Peripheral tolerance to host minor histocompatibility antigens in radiation bone marrow chimeras abrogates lethal GVHD while preserving GVL effect. 758 Nov 9

We have previously demonstrated that BALB/c-H-2k (BALB.K) mice are susceptible to the development of thymic lymphoma induced by E-55+ murine leukemia virus (MuLV). In the present studies, C57BL/10-H-2k (B10.BR) mice were found to be resistant to E-55+ MuLV-induced lymphoma despite the fact that these mice become persistently infected. This resistance to lymphomagensis is mediated by the anti-virus immune response since immunosuppressed mice progress to develop disease. The protective immune response in B10.BR mice is bimodal with respect to time after virus infection. The early immune response results in a dramatic decrease in the number of virus-infected cells within 4-8 weeks after infection. This decrease in virus-infected cells occurs in immunocompetent mice from strains that are either resistant (B10.BR) or susceptible (BALB.K) to E-55+ MuLV-induced disease. Subsequently, susceptible mice develop an increase in infected cells, whereas no increase in infected cells occurs in resistant mice despite the fact that they are persistently infected. This later phase of resistance in B10.BR appears to be mediated by T cells. Since B10.BR and BALB.K both express the H-2k haplotype, resistance appears to be mediated by a non-H-2-linked gene(s). (BALB.K x B10.BR)F1 mice are resistant to disease development, indicating resistance is a dominant trait.
 ...
PMID:Effect of non-H-2-linked genes on anti-virus immune responses and long-term survival in mice persistently infected with E-55+ murine leukemia virus. 764 54

Development of murine AIDS in mice following infection with LP-BM5 murine leukaemia virus (MuLV) is highly strain dependent, with strain differences determined by genes within and outside H-2. Among H-2 genes, the Dd gene is the most closely associated with resistance to LP-BM5 MuLV infection. However, the Dd-mediated resistance is highly influenced by outside H-2 genes, i.e. A lineage strains are more resistant than mice strains of B6/B10 lineage. In this study, the mice having BALB background were analysed and, similarly to A lineage mice, only Dd gene products were found to be required to provide resistance to LP-BM5 MuLV infection. Furthermore, BALB/c Kh mice bearing both Dd and Ld genes clearly showed obviously higher resistance than BALB/c-H-2dm2 mice solely having the Dd gene. In addition, in the long-term observation of the effect of the Dd gene on B6/B10 background mice, D8 mice having the Dd gene as a transgene and expressing a high level Dd gene product showed higher resistance than naturally recombinant B10.A(18R) mice. These results suggest that the MAIDS resistance associated with the D end loci is dependent on the level of expression of an MHC class I gene.
 ...
PMID:Impact of MHC class I gene on resistance to murine AIDS. 766 69

Point mutations of p21 Ras proteins correlate with many human malignancies. To determine whether the mutations of Ras proteins generate immunogenic determinants which can be recognized by T cells and possibly serve as targets for immunotherapy, we studied the murine T helper responses to synthetic Ras peptides corresponding to amino acids 1-23 of normal or mutant Ras protein. Immunization of C3H/He and B10.BR mice with Ras peptides containing a valine mutation at position 12 stimulated MHC class II-restricted T helper cells which recognised specifically the Ras mutation. Surprisingly C57BL/10 mice generated T helper responses not only against mutant but also against normal Ras peptides. Importantly, natural processing of Ras protein was found to generate the epitopes recognized by the peptide-induced T cells.
Leukemia 1993 Aug
PMID:T cell recognition of a point mutation in the P21 Ras protein. 768 74

The use of T cell-specific mAb in vivo for prevention and treatment of graft-vs-host disease (GVHD) and its impact on graft-vs-leukemia (GVL) reactivity was examined in a murine model of MHC-matched bone marrow transplantation (BMT). F(ab')2 fragments of a CD3 epsilon-specific mAb were administered to irradiated AKR (H-2k) hosts after transplantation of BM plus spleen cells from B10.BR donors (BMS chimeras). The effects on GVH and GVL reactivity were Ab dose- and schedule-dependent. A short course of mAb (qe2d, days 0 to 8) prevented clinical evidence of GVHD and mortality. Anti-CD3 F(ab')2 mAb reversed clinical symptoms of acute GVHD when delayed up to 18 days post-transplant. Anti-host (Mls-1a)-specific V beta 6+ cells were absent from the spleens of GVH-negative control mice, but persisted in Ab-treated BMS chimeras despite the absence of GVHD. Leukemic mice given 16.7 micrograms of Ab on days 0, 2, and 4 survived leukemia-free without developing severe GVHD. A longer course of Ab completely prevented GVHD, but led to leukemia relapse in tumor-bearing hosts, despite engraftment of donor T cells. The GVL effect was quantitatively stronger when Ab was used for GVH therapy as compared with GVH prevention. Some Ab-treated, GVH-free chimeras relapsed with lymphomas in unusual sites, suggesting that occult tumor cells may persist in nonlymphoid tissues. These experiments demonstrate that T cell-specific mAb can be used successfully in vivo to avoid severe GVHD, but that excessive or ill-timed administration of Ab may eliminate GVL reactivity.
 ...
PMID:Use of anti-CD3 epsilon F(ab')2 fragments in vivo to modulate graft-versus-host disease without loss of graft-versus-leukemia reactivity after MHC-matched bone marrow transplantation. 773 Jun 53

The development of graft-host tolerance after bone marrow transplantation (BMT) is crucial to avoid the problems of graft-versus-host disease (GVHD) and graft rejection. GVHD can be eliminated by depleting mature donor T cells from the BM inoculum, thereby facilitating the development of graft-host tolerance. However, T-cell depletion often results in an increased incidence of graft rejection and an increased frequency of leukemia relapse. Thus, although graft-host tolerance is a desirable outcome, it can pose a significant threat to leukemia-bearing hosts. Using a major histocompatability complex (MHC)-matched allogeneic model of BMT (B10.BR into AKR), we found that irradiated recipients given donor BM alone displayed mixed T-cell chimerism and did not develop GVHD. Graft-host tolerance developed by 8 weeks after BMT in these chimeras, and they were susceptible to low-dose leukemia challenge. When sufficient numbers of donor spleen cells, as a source of T-cells, were added to the BM graft, AKR hosts developed severe and lethal GVHD. Antihost reactive donor T cells persisted in chimeras undergoing GVHD, indicating that graft-host tolerance did not develop. When administration of the spleen cells was delayed for 7 to 21 days after BMT, there was significantly less mortality because of GVHD. Day 21 was the optimal time for infusion of cells without development of GVHD. Graft-host tolerance was broken by the delayed infusion of donor cells, as indicated by the persistence of antihost-reactive donor T cells in these chimeras in T-cell receptor cross-linking and mixed lymphocyte reaction assays. Importantly, the persistence of antihost-reactive donor T cells correlated with along-term antileukemic effect that was still present at 100 days after transplant. Multiple infusions of immunocompetent donor cells could be administered without increasing the risk for GVHD if delayed until 21 days post-BMT. Delayed infusions of donor spleen cells also resulted in a long-term antileukemic effect in the absence of GVHD in an MHC-haplotype-mismatched model of BMT (SJL into [SJL x AKR]F1). Although delayed infusion of normal donor cells did not induce GVHD, spleen cells from donors previously sensitized to host alloantigens induced GVHD when infused 21 days after BMT. Thus, the ability of previously activated cells to induce GVHD was not inhibited in the same manner as naive cells. Results from limiting dilution analysis assays indicated that alloactivated interleukin-2-secreting CD4+ T cells were preferentially inhibited over cytolytic T cells.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Delayed infusion of immunocompetent donor cells after bone marrow transplantation breaks graft-host tolerance allows for persistent antileukemic reactivity without severe graft-versus-host disease. 775 64

We have recently demonstrated that a short course of high-dose IL-2 administered to lethally irradiated mice leads to marked protection from early and late GVHD mortality, especially when T cell-depleted (TCD) host-type bone marrow cells (BMC) are also administered. IL-2 inhibits the GVHD-inducing activity of donor CD4+ cells without inhibiting their graft-vs.-leukemia effects. Since CD4+ T-lymphocytes produce a variety of cytokines, some of which have recently been implicated in the pathogenesis of GVHD, we have studied the possible effect of IL-2 administration on serum levels of various cytokines. Acute GVHD was induced in lethally irradiated B10 mice by bone marrow transplantation (BMT) with MHC-mismatched allogeneic (A/J) BMC and splenocytes. TCD B10 (host-type) BMC were coadministered to maximize the protective effect of IL-2. Serum cytokine levels were compared in recipients of these inocula with or without a protective course of IL-2 treatment. A marked increase in serum IFN-gamma levels was noted on days 3 through 5 post-BMT in GVHD mice compared with syngeneic BMT control recipients. This GVHD-induced rise in serum IFN-gamma was markedly inhibited in IL-2-protected mice. Murine IL-2 levels were only slightly increased in sera of GVHD mice, and were not influenced by treatment with human recombinant IL-2. Serum levels of the monokines TNF-alpha and IL-1 alpha showed variable early elevations in GVHD mice with or without IL-2 treatment, and were not different from levels observed in syngeneic controls. Serum levels of IFN-gamma, IL-1 alpha, and TNF-alpha all declined markedly by day 7 to 8 post-BMT, when GVHD mortality begins. Administration of neutralizing anti-IFN-gamma mAb did not attenuate and tended to accelerate GVHD mortality, and administration of exogenous IFN-gamma did not overcome the protective effect of IL-2 against GVHD. Together, our results indicate that GVHD is associated with high serum levels of several proinflammatory cytokines in the first week post-BMT, but that these levels decline by the time when GVHD mortality begins. IL-2 specifically inhibits the GVHD-associated production of IFN-gamma, but this inhibition in itself does not explain and may even mitigate the protective effect of IL-2 against early GVHD mortality. However, the demonstration that IL-2 markedly inhibits the production of a GVHD-associated cytokine raises the possibility that alterations in the production of as yet undefined cytokines may be responsible for IL-2-induced GVHD protection.
 ...
PMID:IL-2 inhibits early increases in serum gamma interferon levels associated with graft-versus-host-disease. 780 32

Graft-versus-host disease (GVHD) due to allogeneic bone marrow transplantation can be prevented by depleting the T cells from the marrow graft in vitro. However, the elimination of the donor T cells results in a higher frequency of graft failure, secondary infections and, in case of leukaemia, relapse. We found, that, in contrast to normal spleen cells, spleen cells from A or B10 donor mice pretreated with xenogeneic antithymocyte serum (ATS) in vivo did not induce GVHD in non-irradiated (B10 x A)F1 hybrids. Spleen cells of ATS-pretreated A donors did not cause GVHD in allogeneic CBA mice made neonatally tolerant to the A donor strain either. Furthermore, spleen cells from ATS-treated donors did not cause GVHD in irradiated F1 hybrid recipients, moreover, they decreased the lethal effect of irradiation. The in vivo ATS pretreatment improved the repopulating capacity of spleen cells in irradiated syngeneic recipients, too. The effect of the ATS treatment does not rely solely upon the elimination of T cells, since flow cytofluorometric analysis revealed only a partial depletion of both the CD4+ and CD8+ T cells of the ATS-pretreated animals. These observations may also have clinical relevance.
 ...
PMID:Spleen cells from antithymocyte serum pretreated mice do not induce GVHD but exert increased repopulating activity in irradiated semiallogeneic recipients. 787 94

A murine model for acute myeloid leukemia (mAML) was used to study graft-vs.-leukemia (GVL) effects on residual leukemic cells across both major (MHC) and minor histocompatibility antigens (mHA) barriers. In addition, the therapeutic effect of recombinant human interleukin-2 (rhIL-2)-administered postsyngeneic and allogeneic bone marrow transplantation (BMT) was examined. SJL/J mice inoculated with mAML cells were exposed later to total body irradiation (TBI) and transplanted with bone marrow cells (BMC) mixed with spleen cells derived from normal syngeneic (SJL/J), congenic (B10.S), or allogeneic (C57BL/6) donor mice. One-half of the mice in each group received low dose rhIL-2 for 3 days starting 1 day post-BMT. Spleen cells from treated recipients were transferred to secondary naive SJL/J mice for in vivo detection of residual tumor cells. At a tumor load of 10(5) cells per animal, none of the mice rescued with SJL/J or B10.S cells was cured since 100% of secondary recipients developed leukemia. Concomitant treatment of recipients of B10.S cells with rhIL-2 induced GVL effects since none of the secondary recipients developed leukemia after 2 years. All adoptive recipients of mice rescued with C57BL/6 cells remained free of leukemia after 2 years whether or not rhIL-2 was injected. The potency of the GVL effects observed across mHA and MHC were tumor-cell dose dependent since fewer animals inoculated with 10(6) mAML cells were cured. Only marginal GVL effects were noticed following syngeneic BMT and rhIL-2. Our results sustain the importance of the GVL effects in the treatment of myeloid leukemia and demonstrate that immunotherapy with rhIL-2 following BMT can enhance the therapeutic effect induced by the allograft.
 ...
PMID:Enhancement of GVL effect with rhIL-2 following BMT in a murine model for acute myeloid leukemia in SJL/J mice. 787 38


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>