EC:3.4.24.11 - FACTA Search

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Query: EC:3.4.24.11 (CD10)
9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To assess the potential of photoradiation therapy for the in vitro purging of residual tumor cells from autologous bone marrow (BM) transplants, we studied normal marrow and tumor cell clonogenicity in response to different light-activated compounds by using the fluorescent dyes dihematoporphyrin ether (DHE) and merocyanine-540 (MC-540). After photoradiation of cells with white light, both DHE and MC-540 showed high cytocidal activity toward lymphoid and myeloid neoplastic cells but had a significantly lesser effect on normal granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and mixed colony-forming (CFU-GEMM) progenitor cells. Acute promyelocytic leukemia (HL-60), non-B, non-T, CALLA-positive acute lymphoblastic leukemia (Reh), and diffuse histocytic B cell lymphoma (SK-DHL-2) cell lines were exposed to different drug concentrations in combination with white light at a constant illumination rate of 50,000 lux. With DHE doses varying from 2.0 to 2.5 micrograms/mL and MC-540 concentrations of 15 to 20 micrograms/mL, clonogenic tumor cells could be reduced by more than 4 logs when treated alone or in mixtures with normal irradiated human marrow cells. However, preferential cytotoxicity towards neoplastic cells was highly dependent on the mode of light activation. MC-540 had no substantial effect on malignant lymphoid (SK-DHL-2) and myeloid (HL-60) cells and on normal marrow myeloid (CFU-GM) precursors when drug incubation was performed in the dark and followed by light exposure of washed cells. Equal doses of MC-540 (15 to 20 micrograms/mL) could preferentially eliminate tumor cells under conditions of simultaneous light and drug treatment (30 minutes at 37 degrees C). When using DHE (2.5 micrograms/mL), 29.3%, 46.8%, and 27.5% of normal marrow CFU-GM, BFU-E, and CFU-GEMM, respectively, were spared after sequential drug and light exposure of cells, whereas simultaneous treatment reduced both normal (CFU-GM) and neoplastic cells below the limits of detection. In summary, our results indicate the usefulness of various photoradiation models for the ex vivo treatment of leukemic and lymphomatous bone marrow autografts.
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PMID:Photoradiation models for the clinical ex vivo treatment of autologous bone marrow grafts. 295 18

The effect of rIL-4 on the expression of low affinity receptor for the Fc part of IgE (Fc epsilon R2/CD23) and class II MHC antigens on Burkitt's lymphoma (BL) cell lines was investigated. Some of the BL lines contained low percentages of CD23 and HLA-DQ-positive cells, but virtually all cells expressed HLA-DR. IL-4 induced CD23 and class II MHC Ag expression on 7 of 9 BL. Optimal CD23 and class II MHC expression was observed after 48-72 h of incubation. Induction of CD23 and class II MHC Ag in the BL cell line BL2 by IL-4 was confirmed at the specific mRNA level. Significant activation of HLA-DQ mRNA was obtained after 6 h of incubation with IL-4 and gradually increased during prolonged incubation. Maximal induction of mRNA transcription occurred after 48 to 72 h. Optimal induction of HLA-DR and CD23 transcription in BL2 was also observed after 48 to 72 h. The induction of CD23 and class II MHC Ag seems to be specific for IL-4, because rIL-1, rIL-2, rIFN-gamma, recombinant granulocyte-macrophage-CSF, and a commercial source of low m.w. B cell growth factor were ineffective. In addition, the expression of class I MHC Ag, the transferrin receptor, CD38, CD25, CD10, CD20, and CD21 were not affected by IL-4. Interestingly, IFN-gamma and PGE2 suppressed the IL-4-induced membrane expression of CD23 and class II MHC Ag in a dose-dependent way. IFN-gamma also blocked IL-4-induced CD23 mRNA transcription in BL2 completely, whereas PGE2 (10(-7) M) was partially inhibitory. The induction of CD23 and class II MHC Ag by IL-4 required intact protein synthesis as shown by its inhibition by cycloheximide. These results indicate that the induction of CD23 and class II MHC Ag by IL-4 is regulated in a coordinated way.
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PMID:Regulation of Fc receptor for IgE (CD23) and class II MHC antigen expression on Burkitt's lymphoma cell lines by human IL-4 and IFN-gamma. 296 26

Effective autologous bone marrow transplantation for leukemia and lymphoma is likely to depend upon the selective removal in vitro of malignant cells from normal human bone marrow precursors. Highly specific cytotoxic conjugates formed by coupling ricin A chain to monoclonal antibodies might prove useful for the selective elimination of malignant cells. Consequently, ricin A chain conjugates have been prepared with several different murine monoclonal antibodies and tested for their ability to eliminate clonogenic Burkitt's lymphoma cells from an excess of human bone marrow. The most active reagents included an antibody:A chain conjugate which bound to the nonpolymorphic chain of the la molecule and another which reacted with the mu heavy chain of cell surface immunoglobulin. Conjugates formed with anti-common acute lymphoblastic leukemia antigen, anti-Mr 26,000 glycoprotein, and anti-B1 were much less active on these Burkitt's cells, contrasting with results of complement-dependent tumor cell lysis. Tumor cell kill was partially inhibited by the addition of greater than 2 X 10(6) human bone marrow cells/ml but could be potentiated by increasing the concentration of conjugate or by the addition of 10 mM ammonium chloride. In the presence of ammonium chloride, at least 4 logs of clonogenic tumor cells could be eliminated within 24 h from a 20-fold excess of bone marrow using 10(-7) M ricin A chain linked to one or two different antibodies. Similar treatment of normal human bone marrow temporarily inhibited granulocyte-macrophage colony-forming units (cell) formation but did not compromise establishment of continuous bone marrow cultures. The degree of selective elimination of tumor cells with A chain antibody conjugates was comparable to that achieved with 4-hydroperoxycyclophosphamide or with multiple monoclonal antibodies and complement.
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PMID:Elimination of clonogenic tumor cells from human bone marrow using a combination of monoclonal antibody:ricin A chain conjugates. 351 Jul 20

Various chemical compounds have been described to induce photosensitization of tumor cells resulting in cell death. We studied the effect of merocyanine-540 (MC-540) on both leukemic and normal bone marrow (BM) cells. Acute promyelocytic leukemia (HL-60) and common acute lymphoblastic leukemia antigen-positive non-T, non-B acute lymphoblastic leukemia (Reh) cell lines were incubated with MC-540 and simultaneously exposed to white light. Normal human BM and mixtures of leukemic cells with BM cells were treated under similar conditions. At constant illumination rates of 50,000 lx, significant (at least 4 to 5 logs) tumor cell destruction was obtained with MC-540 concentrations of 20 micrograms/ml or more for HL-60, and 10 micrograms/ml or more for Reh cells. Incubation of BM under equivalent conditions preserved 18.0% of granulocyte-macrophage colony-forming units and 14.2% of erythroid burst-forming units. Similar results were obtained when tumor cells were mixed with irradiated BM and then treated with MC-540. In summary, cell photosensitization with MC-540 has a selective cytotoxic effect towards leukemic cells and therefore may be useful for purging tumor cells from autologous BM.
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PMID:Comparison of the cytotoxic effects of merocyanine-540 on leukemic cells and normal human bone marrow. 375 50

One requirement for autologous bone marrow transplantation is the selective removal of malignant cells from normal marrow precursors. Development of a clonogenic assay that detects elimination of up to 5 logs of Burkitt's lymphoma cells in the presence of a 20-fold excess of human bone marrow has permitted the evaluation of two different methods for the selective removal of malignant cells. Treatment with 4-hydroperoxycyclophosphamide (4-HC) (60 to 100 micrograms/mL) eliminated 2.0 to 3.5 logs of clonogenic cells. Antitumor activity depended upon the concentration of 4-HC and the length of incubation, but not upon the concentration of normal bone marrow cells. Comparable removal of clonogenic Burkitt's cells was achieved by treatment with rabbit complement (C') and a combination of J5 anti-common acute lymphoblastic leukemia antigen (J5 anti-CALLA), J2 anti-gp 26, and the B1 anti-B1 murine monoclonal antibodies. A combination of 4-HC and monoclonal antibodies proved slightly but significantly more effective than either single agent in eliminating clonogenic tumor cells. Although treatment with 4-HC markedly reduced granulocyte-macrophage colony-forming units-C (GM-CFU-C) content of human bone marrow, neither treatment with 4-HC nor treatment with monoclonal antibodies and C' eliminated precursor cells that could generate new GM-CFU-C after growth in continuous bone marrow cultures. Our data suggest that treatment with 4-HC in combination with multiple monoclonal antibody reagents could be a safe and effective method of eliminating clonogenic tumor cells from human bone marrow.
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PMID:Elimination of clonogenic Burkitt's lymphoma cells from human bone marrow using 4-hydroperoxycyclophosphamide in combination with monoclonal antibodies and complement. 399 66

Single- and multicolor flow cytometry were used to define progenitor subsets in normal human bone marrow and peripheral blood, cord blood, and blood following mobilization of CD34+ progenitor cells by cyclophosphamide or cyclophosphamide/etoposide/G-CSF treatment. CD34 cells were quantitated and subsets of CD34+ cells were defined by coexpression of CD33, CD13, CD10, CD19, CD45RA, and CD71. Myeloid and erythroid progenitors were quantitated by sorting single CD34+ cells into individual wells of 96-well plates containing methylcellulose, IL-3, GM-CSF, G-CSF, IL-6, and erythropoietin. Comparative studies of CD34 cells showed that the percentage of CD34+ mononuclear cells was greatest in blood samples from patients following mobilization treatment with cyclophosphamide/etoposide/G-CSF averaging 2%. By comparison, the remaining sample groups ranged from 1.68 to 0.15% CD34 cells in this order, bone marrow > cord blood > cyclophosphamide mobilized blood > peripheral blood. Comparison of CD34 cells per milliliter of bone marrow or blood showed a range of 22.4 x 10(4) to 0.65 x 10(4)/ml in the following order, bone marrow > chemotherapy/etoposide/G-CSF > cord blood > cyclophosphamide-mobilized blood. Comparative analysis of CD34 subsets from different sources showed significant differences, particularly bone marrow and blood samples. A distinct population of CD34+ CD19+ (Leu 12) CD10+ (CALLA) pre-B lymphocyte cells was defined in bone marrow with lower side and forward light scatter characteristics and was variable between donors (29.8 +/- 16.9%, mean +/- 1 SD; range, 3-54%; n = 8). This population was not found to a significant degree in blood and also expressed CD45RA (Leu 18). Coexpression studies of CD45RA and CD71 (transferrin receptor) expression on CD34+ cells defined a CD45RA- CD71+ population containing 89 +/- 6.3% (n = 4) BFU-E and a CD45RA+ CD71+ population that contained all CFU-GM (n = 4). LeuM7 (CD13) stained a larger percentage to a greater intensity than MY7 (CD13). Coexpression of CD45RA (Leu 18) and CD13 (LeuM7) defined a subset of CD13+ CD45RA+ cells enriched for CFU-GM and CFU-M with a cloning efficiency of 31%. Coexpression of CD33 (MY9) and CD13 (MY7) defined a population that was predominantly CFU-GM with a cloning efficiency of 38%. These studies define CD34+ phenotypes containing pure populations of B lymphocyte, granulocyte-macrophage, or erythroid progenitors and demonstrate the utility of multiparameter flow cytometry to define lineage-committed CD34+ cells.
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PMID:Phenotypic analysis and characterization of CD34+ cells from normal human bone marrow, cord blood, peripheral blood, and mobilized peripheral blood from patients undergoing autologous stem cell transplantation. 750 11

We have recently reported that a combination of lymphokine-activated killer (LAK) cells and bispecific antibodies (BsAb) efficiently lysed autologous and allogeneic leukemic blasts that had surface antigens reactive with the BsAb. The effector cells used in that experiment were peripheral blood mononuclear cells stimulated with interleukin-2 (IL-2) for 2 weeks, with the initial addition of anti-CD3 moAb; these were termed T3-LAK effector cells. In this study, we examined the effects of T3-LAK cells and BsAb on autologous normal CD34+ BM cells in both cytotoxicity and colony formation assays. When T3-LAK cells were incubated with CD34+ BM cells, low levels of cytotoxicity were induced against the CD34+ BM cells and the cytotoxicity was enhanced by the addition of anti-CD3 Fab' x anti-CD 13 Fab' BsAb but not by the addition of anti-CD3 Fab' x anti-CD10 Fab' BsAb. This enhancement appeared to be due to the lysis of CD34+CD13+ BM cells. When T3-LAK cells were preincubated with CD34+ BM cells in the presence or absence of the BsAb and plated for colony assay, neither the T3-LAK cells nor the BsAb affected granulocyte-macrophage or mixed-cell colony formation by CD34+ BM cells. Taken together with our previous finding that T3-LAK cells used in combination with the BsAb markedly inhibited colony formation by leukemic progenitor cells, these results indicate that this combination provides a potential new strategy for CD34+ BM cell purging in autologous BMT.
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PMID:Combination of interleukin-2-stimulated lymphocytes and bispecific antibodies that efficiently lyse leukemic cells does not affect bone marrow CD34-positive stem cell function in vitro. 752 85

Bone marrow (BM) is most frequently used to transplant hematopoietic progenitor cells, but umbilical cord blood (UCB) and mobilized peripheral blood (PB) provide alternative sources of progenitor cells for transplantation. To study whether the clonogenicity and phenotype of progenitor cells vary between the compartments, CD34+ cells from UCB, mobilized PB, and BM were analyzed for in vitro colony formation and characterized by immunophenotyping for several lineage-associated and maturation-related cell surface molecules. We found that circulating CD34+ cells, either from PB after granulocyte colony-stimulating factor (G-CSF) mobilization or from UCB, contained a large proportion of cells (86-96%) with myeloid cell-associated molecules (CD33 and CD13) and clonogenic cells (colony-forming unit-granulocyte-macrophage and burst-forming unit-erythrocyte) in excess of BM CD34+ cells. Further, UCB and PB CD34+ cells contained > or = 3% cells with a phenotype associated with immature (HLA-DR- and CD38-) progenitor cells, which was comparable to what is found among BM CD34+ cells. The proportion of CD34+ cells in UCB expressing the B cell-associated molecules (CD10 and CD19) was comparable to that found in mobilized PB (< or = 5%) but significantly lower than for BM CD34+ cells (19-24%). Further, we observed a higher proportion of CD34+ cells expressing the T cell-associated molecule CD7+ in UCB (7%) compared with both PB and BM (3-4%). In general, circulating CD34+ cells, either from UCB or G-CSF-mobilized PB, display largely the same phenotypic profile and clonogenicity, being different from resident CD34+ cells in BM.
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PMID:Comparison of the phenotype and clonogenicity of normal CD34+ cells from umbilical cord blood, granulocyte colony-stimulating factor-mobilized peripheral blood, and adult human bone marrow. 753 6

Enkephalinase-blocking agent thiorphan was added to long-term cultures of mouse bone marrow cells at the time of culture initiation (time 0) or 2 weeks thereafter, when the stromal layer appears. Cellularity, cell morphology (in cytospin smears) and the yield of granulocyte-macrophage progenitor cells (GM-CFC assay in agar) were recorded. Low concentrations of thiorphan accelerated recovery of the cultures after an initial drop of the cell count. Expansion and maturation of the granulocytic lineage was promoted, with parallel decline of the GM-CFC yield. Thiorphan probably interfered with the activity of enkephalinase (endopeptidase 24.11) in the cultures. That enzyme is the CD10 surface marker (CALLA) of lymphoid, myeloid and stromal elements.
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PMID:Enkephalinase-blocking agent thiorphan affects cell growth and differentiation in long term culture of mouse bone marrow. 856 66

The class III receptor tyrosine kinase FLT3/FLK2 (FLT3; CD135) represents an important molecule involved in early steps of hematopoiesis. Here we compare cell-surface expression of FLT3 on bone marrow (BM) and cord blood (CB) cells using monoclonal antibodies (MoAbs) specific for the extracellular domain of human FLT3. Flow cytometric analysis of MACS-purified BM and CB cells showed that 63% to 82% of BM CD34+ and 88% to 95% of the CB CD34+ cells coexpress FLT3. Clonogenic assays and morphological characterization of FACS-sorted BM CD34+ cells demonstrate that colony-forming unit-granulocyte-macrophage (CFU-GM) and immature myelo-monocytic precursor cells are enriched in the subpopulation staining most brightly with the FLT3 MoAb whereas the majority of the burst-forming units-erythroid (BTU-E) and small cells with lymphoid morphology are found in the FLT3- population. In contrast, statistically indistinguishable proportions of CFU-granulocyte-erythrocyte-megakaryocyte-macrophage (CFU-GEMM) and more primitive cobblestone area forming cells (CAFC) were detected in both fractions, albeit the FLT3+ fraction consistently showed more CAFC activity than the FLT3- fraction. Although in both, BM and CB the majority of CD34+CD117+ (KIT+), CD34+CD90+ (Thy-1+), and CD34+CD109+ cells coexpress FLT3, three-color phenotypic analyses are consistent with the functional findings and suggest that the most primitive cells defined as CD34+CD38-, CD34+CD71low, CD34+HLA-DR-, CD34+CD117low, CD34+CD90+, and CD34+CD109+ express low levels of cell-surface FLT3 and were therefore not enriched to a statistically significant extent with the bright versus negative sorting scheme. Thus, clear segregation of the most primitive progenitors from BM CD34+ cells was confounded by low apparent levels of FLT3 cell-surface expression on these cells, whereas myeloid progenitors unambiguously segregated with the FLT3 brightest cells and erythroid progenitors with the FLT3 dimmest. Additional phenotypic analyses using MoAbs against progenitor/stem cell markers including the mucinlike molecule MGC-24v (CD164), the receptor tyrosine kinases TIE, FMS (CD115), and KIT (CD117) further illustrate the differences in surface antigen expression profiles of BM and CB CD34+ cells. Notably, CD115 is rarely detected on CB CD34+ cells, whereas 20% to 25% of the BM CD34+FLT3+ cells are CD115+. Furthermore, 80% to 95% of the CB CD34+CD117+ but only 60% to 75% of the BM CD34+CD117+ cells coexpress FLT3. Only a negligible amount of CD34+CD19+ are detected in CB, while in BM 20% to 30% of CD34+CD19+ presumed pro/pre-B cells coexpress FLT3. In contrast, the majority of the CD34+CD164+ and CD34+TIE+ subsets in both CB and BM coexpress FLT3. Analysis of unseparated cells showed that FLT3 expression is not restricted to CD34+ subsets. About 65% to 70% of lymphocyte-gated BM CD34-FLT3+ cells are positive for the monocytic marker CD115 whereas 25% to 30% of these cells consist of CD10 expressing B-cell precursors. Finally, CD34- monocytes in BM, CB, and PB express FLT3 whereas granulocytes are FLT3-. Our data show that detectable FLT3 appears first at low levels on the surface of primitive multilineage progenitor cells and disappears during defined stages of B-cell development, but is upregulated and maintained during monocytic maturation.
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PMID:Functional and phenotypic characterization of cord blood and bone marrow subsets expressing FLT3 (CD135) receptor tyrosine kinase. 920 45

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