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

Thymus-leukemia (TL) antigen is a class I molecule of the major histocompatibility complex that is expressed on the surface of mouse cortical thymocytes. Though not expected, it has been reported that TL antigen can be found on isolated mitochondria of TL+ cells. We used immuno-cryoultramicrotomy to look for TL on mitochondria in situ, thereby avoiding the plasma membrane contamination that occurs when isolating organelles. Establishing optimal fixation conditions was crucial, as mitochondrial structure was not preserved by the low concentrations of fixative needed for detection of antibody labeling. The plasma membranes of tissue culture and thymus cells were labeled well with anti-TL antibody and protein A-gold conjugate, while mitochondria within the cells were not labeled. Isolation of mitochondria on a one-step Ficoll gradient resulted in a purer organelle preparation than did isolation of mitochondria by centrifugation alone. Generally, mitchondria within this purer preparation were not labeled. Our data show that under conditions where contamination by plasma membrane is not a major concern, TL antigen cannot be detected on mitochondria.
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PMID:Cellular location of thymus-leukemia (TL) antigen as shown by immuno-cryoultramicrotomy. 188 98

Inbred mouse genomes contain two subclasses of proviruses related to mink cell focus-forming (MCF) retroviruses: polytropic (Pmv), and modified polytropic (Mpmv). To determine whether one of these subclasses is associated with murine lupus, oligonucleotide probes specific for Pmv or Mpmv sequences were used in Northern analyses. Thymus 8.4 kb Mpmv RNA was expressed in five of five lupus-prone strains and crosses and this expression was not affected by genes that retard or accelerate development of lupus. Two of four leukemia-prone strains expressed low levels of such thymic transcripts, but none of 11 control strains did. 8.4 kb Mpmv RNA expression was not induced in thymuses of control mice by the lpr/lpr or gld/gld genotypes (which cause polyclonal immune activation) nor by treatment with mitogens. In contrast to Mpmv, thymic 8.4 kb Pmv expression was poorly associated with autoimmunity: it was easily detected in nearly all strains, and was increased by polyclonal activation in control mice. These studies indicate that the organ-specific thymic 8.4 kb Mpmv expression (a) is characteristic of several genetic backgrounds which predispose to murine lupus, (b) precedes and does not correlate with disease development, (c) is not due to polyclonal activation, and (d) is regulated independently of 8.4 kb Pmv expression.
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PMID:Analysis of thymic endogenous retroviral expression in murine lupus. Genetic and immune studies. 220 23

Radiation Leukemia Virus (RadLV) is a retrovirus, which displays a highly specific thymotropism; after inoculation into young C57 BL/Ka mice, active virus replication is observed only in thymocytes and thymic lymphomas develop in most treated mice. The specific interaction between RadLV and the thymus resides in the particular susceptibility to infection of the most immature cells involved in the intrathymic lymphoid differentiation pathway and of non lymphoid thymic stromal cells. Recent data obtained from 'in situ' hybridization studies for detection of viral transcripts yield more detailed informations on these intriguing interactions.
Thymus 1989
PMID:Radiation leukemia virus: a marker for the study of intrathymic T cell differentiation. 256 Feb 69

Accumulating evidence has shown that thymic stromal-lymphoid interactions play a major role in the development of AKR thymic leukemia. A normal thymic stromal cell (TSC) line B6TE-A, which has been shown to support the in vitro growth of AKR leukemic T cells by forming multicellular complexes with them, was used to raise monoclonal antibodies. Three of these mAb, MTS 31, 32 and 38, in addition to 2 other MTS mAb, are abnormally expressed in the preleukemic and/or leukemic stages in AKR mice. These 5 MTS mAb, which detect antigens on both subpopulations of TSC and T cells, show some reduced cortical reactivity from the pre-leukemic period (MTS 32 and 35) to markedly depressed reactivity in the leukemic period (MTS 31, 32, 33, 35 and 38). While it appears that the major reduction is due to the loss of antigens from the cortical thymocytes, there is some indication that the stromal elements may be affected also. In addition, MTS 29, which was also produced in this study, while only reacting with rare thymic medullary cells in situ was densely distributed on cultured stromal cells from both normal and leukemic thymuses. In this report, the value of these MTS mAb for documenting various stages of AKR leukemogenesis has been clearly demonstrated: their possible modulatory effects on in vitro T cell leukemia growth is currently being investigated.
Thymus 1989
PMID:Antigens shared by thymic stromal cells and T lymphocytes are abnormally expressed in AKR thymuses. 262 44

A retrovirus element (TLev1) is located within the Thymus leukemia antigen (Tla) locus of the C57BL/10 mouse major histocompatibility complex. Low-copy probes have been isolated from sequences flanking the TLev1 integration site to examine the distribution of TLev1 among inbred mouse strains having genotypically determined variations in TL-antigen expression. It was found that the low-copy probes cross-hybridize to regions within the Tla locus in a genotype-specific manner. Although a strong association was found between TL mouse strains and TLev1, the presence or absence of the TLev1 locus did not exclusively correlate with expression or nonexpression of TL antigens. Analysis of different Mus subspecies indicates that TLev1 integrated into a common ancestor of the species Mus musculus. It is suggested that the loss of the TLev1 locus from certain mouse genomes reflects evolutionary rearrangements in the TL region; the resulting diversity may relate to the differential expression of TL antigens among mouse strains. The probes described here provide a useful tool for examining the genomic expansions and contractions which have occurred during the evolution of the Tla locus.
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PMID:Genomic organization of the mouse Tla locus: study of an endogenous retroviruslike locus reveals polymorphisms related to different Tla haplotypes. 290

Fusion products of spleen cells of W/FuDp rats immunized with a methylcholanthrene-induced BALB/c sarcoma, CA-2, and mouse myeloma cells were screened in an attempt to identify a monoclonal antibody defining the individually distinct tumor-specific transplantation antigen of CA-2. A hybridoma, MP/69/04, was isolated which produces an IgG2a monoclonal antibody that recognized a tumor-restricted antigen of CA-2. In direct binding assay, MP/69/04 reacted only with 2 of 15 methylcholanthrene induced BALB/c sarcomas tested. Thymus, spleen, lymph nodes, bone marrow, brain, adult lung fibroblasts, newborn muscle fibroblasts and 3T3 cells were negative. Absorption tests revealed, however, expression of the MP/69/04 determinant on 8 of the 12 murine leukemia virus (MuLV) producer BALB/c sarcoma tested. The antigen was not detected on any of the three non-producer sarcomas tested nor on a wide range of normal tissues and cell lines. An N-dualtropic MuLV was isolated from CA-2, and cell lines susceptible to infection by this virus were shown to express the MP/69/04 epitope. By Western blotting, the MP/69/04 epitope was identified as being expressed on the MuLV structural protein with a molecular weight of 12,000, present in CA-2 cells and in the purified CA-2 MuLV. These results indicate the MP/69/04 antigen is not a unique tumor-specific transplantation antigen but is a gag product of a recombinant retrovirus which is expressed on the cell surface of many MuLV + methylcholanthrene-induced BALB/c fibrosarcomas.
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PMID:Cell surface antigens of chemically induced fibrosarcomas: detection by a monoclonal antibody of a tumor-restricted Mr 12,000 protein gag antigen encoded by a dual-tropic murine leukemia virus. 299 69

Although cortical thymocytes were found to be the predominant ecotropic and MCF-virus producers in the thymus of leukemia prone AKR mice the initial ecotropic retrovirus producing cells have been detected among a low density subpopulation of thymocytes including both PNA(+) and PNA(-) cells. Leukemosuppressive anti-viral treatment of these animals results in several important changes in the AKR thymus, including the elimination of virus producing cells, the induction of cellular phenotypic alterations, a decreased ability to bind ecotropic and MCF virus, a resistance to challenge with leukemogenic exogenous retroviruses, and the apparent elimination of a population of virus producing radioresistant cells. In addition, complement-mediated depletion with anti-viral IgG resulted in the complete elimination of proliferating thymocytes. These results suggest that passive anti-viral immunotherapy effectively eliminates a population of thymocytes which serve as the neonatal source of endogenous retroviruses and interferes with the earliest stages of leukemogenesis in AKR mice.
Thymus
PMID:The effects of leukemosuppressive immunotherapy on thymic infectious cell centers in AKR mice. 326 51

Over 300 individuals have received fetal liver transplants for a spectrum of disorders including immunodeficiencies, aplastic anemia, leukemia and genetic disorders. In some instances, the objective has been to reconstitute the immune system from fetal liver-derived lymphoid stem cells. In aplastic anemia and leukemia two distinct approaches have been used: engraftment of fetal liver-derived hematopoietic stem cells or attempts to stimulate recovery of autologous hematopoiesis via factors produced by fetal liver. In genetic disorders, partial engraftment of fetal liver-derived hematopoietic and hepatic cells has been investigated. This report critically reviews data presented at a symposium on fetal liver transplantation in New-Delhi, 1-5 February 1986.
Thymus 1987
PMID:Synopsis and prospectives on fetal liver transplantation. 332 98

Forty-five patients with acute myelogenous leukaemia (AML) received induction chemotherapy with either a conventional dose of cytarabine and daunorubicin (27 patients) or a low dose of cytarabine (18 patients). Maintenance chemotherapy was given to all responders. In 14 of 39 evaluable patients, infusion of fetal liver cells from 10-24 weeks old foetuses was given following induction as well as maintenance therapy. Six of 14 patients (43%) achieved a complete remission; 2 showed evidence of transient engraftment documented by analysis of sex chromosomes and RBC antigens (1 patient each). Fetal liver infusion within 6 days of completing induction chemotherapy appeared more effective than when given later. Five of 25 patients (20%) who did not receive fetal liver infusion achieved a complete remission. The present work suggests that fetal liver infusion given following induction chemotherapy may increase the remission rate in AML either by temporary engraftment or by accelerating the rate of haematological recovery.
Thymus 1987
PMID:Fetal liver infusion in acute myelogenous leukaemia. 332

One hundred patients with severe aplastic anemia were treated and evaluated in a prospective study at our hospital between January 1976 and October 1983. 28 patients had a HLA-identical sibling donor and were treated with bone marrow transplantation. 72 patients without a HLA-identical sibling donor were given antilymphocyte globulin followed by oral low dose androgen therapy. One and a half years to nine years after treatment 13 patients (46%) survive in the transplant group and 53 patients (74%) survive in the second group. All except one in the second group have self-sustaining hematopoiesis without need for transfusions. There is one major difference between the two therapies. Marrow transplantation restores bone marrow function completely and no late hematological complications have been seen in this group. The majority of patients treated with antilymphocyte globulin in contrast have residual abnormalities of hemopoiesis: macrocytosis, mild granulocytopenia and mild thrombocytopenia. Relapse (11 of 72 patients) and clonal hematological disorders, such as paroxysmal nocturnal hemoglobinuria (4 patients) and leukemia (one patient) can occur years after complete bone marrow reconstitution with antilymphocyte globulin. These late disorders are of concern. In spite of this we conclude that antilymphocyte globulin treatment is an effective therapy with low early mortality and morbidity and a high chance for a long sustained remission. Results are better or at least equivalent to bone marrow transplantation and patients with donors should be given the option of transplantation or antilymphocyte globulin.
Thymus 1987
PMID:A comparison between ALG and bone marrow transplantation in treatment of severe aplastic anemia. 332 3


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