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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bone marrow-derived leukocytes of murine epidermis can express two phenotypes: typical Langerhans cells, which are Ia+ and Thy-1-, and a recently discovered second population that is Thy-1+ and Ia-. To verify that these phenotypes are expressed by two different cell types, and to help understand their lineage and function, we have studied morphology and reactivity with a large panel of antibodies. Dual antibody immunofluorescence combined with electron microscopy showed that Thy-1+ and Ia+ cells were each distributed in a regular fashion and formed adjacent dendritic systems in or close to the basal layer. Double-labeling studies with anti-Ia and a second monoclonal antibody revealed that all Langerhans cells expressed F4/80 (macrophage), Mac-1 (C3bi receptor), and 2.4G2 (Fc receptor), as well as the thymus leukemia (TL) and heat-stable (M1.69/16) antigens. A large fraction expressed S100 and all exhibited membrane ATPase and nonspecific esterase. In contrast, Thy-1+ cells lacked all these features of Langerhans cells, except that a minority were strongly reactive with 2.4G2. Thy-1+ cells also lacked differentiation antigens of most other types of leukocytes, except they were rich in asialo GM1. By electron microscopy, Thy-1+ cells had cytoplasmic granules that were similar in structure and in their aryl sulfatase content to those previously described in natural killer cells. The granules were enlarged in beige mice, suggesting a lysosomal origin, and were present in mast cell-deficient W/Wv mice, indicating no relation to mast cells. We conclude that Thy-1+ epidermal cells are thoroughly distinct from Langerhans cells. On the basis of morphology and phenotype, they may represent a type of tissue natural killer cell. Thy-1+ natural killer cells are now being identified in several nonlymphoid sites, such as gut epithelium and the livers of mice given adjuvants. If Thy-1+ epidermal cells prove to be natural killer cells, it is noteworthy that they represent a resident population regularly distributed in the basal layer of all mouse strains. The notion that Thy-1+ epidermal cells are immature natural killer cells is intriguing in light of recent evidence that Ia+ Langerhans cells are also immature with respect to accessory cell function. The epidermis may not have the functional capacities of a lymphoid organ, but it could contribute immature cells important for both natural and acquired resistance.
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PMID:The Thy-1-bearing cell of murine epidermis. A distinctive leukocyte perhaps related to natural killer cells. 286 Dec 45

Rat basophilic leukemia (RBL) cells were shown to bind mouse monoclonal (MC) IgE and certain mouse monomeric IgG1 and IgG2b monoclonal antibodies (MAb) by using a haptenated sheep red blood cell (SRBC) rosetting assay. Rosette formation was antibody concentration dependent with all three immunoglobulin isotypes, but at least 100 times more IgG than IgE was required to form a similar number of rosettes. It was shown by FACS analysis and rosette formation that a subset (8/23) of the IgG MC was able to bind to RBL cells as monomers. However, the majority 15/23 did not bind or bound weakly (less than 25% rosettes) unless in the form of antigen-antibody complexes. As complexes, all IgG subclasses except IgG3 could produce rosettes with RBL cells. None of the IgM or IgA MC tested formed rosettes, even in complexed form. By inhibition studies it is demonstrated that mouse IgG1, IgG2a, and IgG2b MC bind to the same Fc receptor. Mouse IgE was only partially able to inhibit IgG-dependent rosettes at high concentrations, and none of the IgG MC were able to inhibit IgE-dependent rosettes. These results suggest that the interaction of mouse IgG is quite specific for the RBL cell FcG receptor. Because deaggregated polyclonal mouse IgG was a weak inhibitor of MC IgG sensitization of RBL cells, the results are discussed in terms of the heterogeneity and possible abnormality of some MAb.
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PMID:The interaction of monomeric and complexed mouse monoclonal IgG with rat basophilic leukemia cells: a subset of IgG molecules can bind to RBL cell Fc receptors for IgG. 294 53

Rat basophilic leukemia (RBL) cells carry two surface glycoprotein molecules named R (or alpha) and H which, when detergent solubilized, bind to rat IgE-Sepharose. The same two molecules also bind to rat IgG-Sepharose but with a lower affinity. R is a component of the high affinity Fc receptor for IgE. In the present study the inhibition of the binding of R and H to rat IgG-Sepharose by various homologous and heterologous immunoglobulins was used to assess their relative affinities for the two receptor molecules. Ranking the rat immunoglobulins in order of their affinities for the R receptor yielded: IgE much greater than IgG2a greater than IgG1 greater than IgG2b; and for H: IgE greater than IgG2b greater than IgG1 greater than IgG2a. Rat IgG2c inhibited the binding of both R and H but a precise ranking could not be assigned. Conclusive evidence has been obtained for the Fc specificity of these interactions. The affinities of the mouse IgG subclass/R interactions can be ranked: IgG1 greater than IgG2a greater than IgG2b; and for the H receptor: IgG1 greater than IgG2b greater than IgG2a. All of the mouse proteins and other heterologous IgGs, such as those of sheep, goat, equine and rabbit origin, interacted considerably more strongly with H than with R. No interaction with mouse IgG3 could be detected under the conditions tested.
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PMID:The interaction of IgG subclasses with solubilized Fc receptors of rat basophilic leukemia cells. 297 Nov 36

Lymphocyte transformation/activation is accompanied by the induction of a variety of the inducible receptors associated with the activation antigens. The p55 chain of the interleukin-2 receptor (IL-2R/p55) recognized by anti-Tac monoclonal antibody (mAb) is expressed on activated T and B cells as well as natural killer (NK) cells. IL-2R/p55(Tac) is constitutively expressed on T4(+) T cells transformed by human T-lymphotropic virus I (HTLV-I), which is a causative agent for adult T-cell leukemia (ATL). Low affinity Fc receptor for IgE (Fc epsilon R2/CD23) is another inducible receptor binding IgE and is expressed on various hematopoietic cell types. While the physiological expression of Fc epsilon R2 and its soluble form (IgE Binding Factor; IgE BF) is variably regulated by cytokines and IgE, there is a constitutive expression of Fc epsilon R2 on Epstein-Barr virus (EBV) transformed B cell lines and some of HTLV-I (+) T cell lines. ATL-derived factor (ADF) has been characterized as an IL-2R/p55(Tac) inducing factor derived from HTLV-I(+) T cell lines. Purification of ADF protein and the cDNA cloning proved that ADF is closely related to the autocrine growth factor produced by an EBV(+) B cell line 3B6 (H. Wakasugi and T. Tursz) and belonging to the family of thiol reducing co-enzyme thioredoxin which is involved in many biological reactions. Recombinant ADF produced by COS cells and E. coli showed both IL-2R inducing and reducing activities. We will discuss the biological roles of ADF in viral and normal lymphocyte activation and transformation in relation to the receptor gene activation.
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PMID:IL-2 receptor and Fc epsilon R2 gene activation in lymphocyte transformation: possible roles of ATL-derived factor. 297 20

The human monoblast leukemia line U937 is growth inhibited and induced to express various characteristics of mature monocytes by lymphokines (LK) and other cytokines. Previous experiments have shown that interferon-gamma (IFN-gamma) is responsible for some but not all of the differentiation-inducing effects on U937. To determine the variety and specificity of activity, the following factors were studied: phytohemagglutinin-induced LK that contained IFN-gamma (100 units/ml); purified IFN-gamma; human colony-stimulating factor 1 (CSF-1); and conditioned medium(a) (CM) from the human bladder carcinoma cell line 5637 and the hepatoma cell line SK-HEP. LK preparations contained no colony-stimulating activity, whereas CM from 5637 and SK-HEP both contained granulocyte-macrophage CSF (3000 to 4000 units/ml) but no IFN activity. IFN-gamma is the major immunoglobulin G Fc receptor-inducing species within lymphokine, since anti-interferon-gamma antibody inhibited most of this activity. Other sources of Fc receptor-inducing activity were CM from SK-HEP and 5637 cell lines. Human CSF-1 when tested up to 800 units/ml was inactive for Fc receptor induction. LK induced the chemotactic peptide receptor, but this induction was due to factors other than IFN-gamma as anti-IFN-gamma antibody did not inhibit the induction, and purified IFN-gamma at a dose equivalent to that found in LK (100 units/ml) had no activity in the assay. SK-HEP and 5637 CM had strong chemotactic peptide receptor-inducing activity, but human CSF-1 was inactive up to 800 units/ml. Peroxide production after stimulation with phorbol myristic acid could be induced by LK, LK with anti-IFN-gamma antibody, 5637, and SK-HEP treatment. IFN-gamma (100 units/ml) and CSF-1 (800 units/ml) were ineffective. Peroxide production was induced by IFN-gamma at concentrations above 1000 units/ml. The inducibility of several enzymatic activities was determined as additional measures of maturation. N-Acetylglucuronidase was induced, for example, by LK, IFN-gamma, 5637 CM, and phorbol myristic acid. Alkaline phosphatase was induced by LK, IFN-gamma, dexamethasone, and phorbol myristic acid. 1,25-Dihydroxycholecalciferol was also examined and could induce most of the maturational markers examined. The results demonstrate that non-IFN cytokines from several sources have profound differentiation-inducing effects on monoblast leukemia cells in a pattern different from that of IFN-gamma.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Distinct activities of interferon-gamma, lymphokine and cytokine differentiation-inducing factors acting on the human monoblastic leukemia cell line U937. 298 Nov 61

The effects of hot-water extract of pine cone (PCE) of Pinus parviflora Sieb. et Zucc. on the growth and differentiation of ML-1 cells, derived from a patient with human myeloblastic leukemia, were investigated. Growth of ML-1 cells was slightly inhibited at 3% (v/v) PCE, and a cytotoxic effect appeared at greater than 10%. Growth inhibition was accompanied by conversion to morphologically macrophage-like cells with alpha-naphthyl acetate esterase activity. In contrast, PCE dose-dependently increased the Fc receptor and nitroblue tetrazolium (NBT)-reducing activity up to 3%; above 3% its effect declined. Most of the cytotoxic activity was extracted from PCE with ethanol, and separated from the insoluble pellet, which contained the differentiation-inducing activity. The differentiation-inducing activity was eluted near the void volume on Sephadex G-200 gel filtration, with a 260-fold increase in the specific activity.
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PMID:Partial purification of novel differentiation-inducing substances(s) from hot water extract of Japanese pine cone. 308 16

The results presented here indicate that recombinant murine interferon-gamma can cause a dramatic differential induction of two distinct class I MHC molecules. Thus, IFN-gamma treatment of the murine leukemia virus (MuLV)-induced AKR SL3 tumor, a cell line that normally expresses moderate levels of class I MHC antigens, resulted in a large increase in H-2Dk expression, but no change or a slight decrease in H-2Kk expression as measured by cytofluorography. Explanations of the selective enhancement of Dk expression based on increased Fc receptor display or differential kinetics of induction were ruled out. The phenomenon was observed over a wide range of doses of IFN-gamma and with two different monoclonal antibodies to Kk, the latter finding making it unlikely that an altered form of the Kk molecule was induced. The same differential induction of the Dk antigen was observed for the LBRM.5A4 tumor cell line. Because LBRM.5A4 is also MuLV+ but of congenic B10.BR (H-2k) origin, these results were consistent with the possibility that such differential induction was associated with the H-2k haplotype and/or MuLV. The implications of these results, as a possible mechanism of tumor cell escape from an immune surveillance system monitored by class I MHC-restricted T cells and as a useful model system to dissect the mechanism of IFN-gamma induction of class I MHC antigens, are discussed.
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PMID:Differential induction of H-2K vs H-2D class I major histocompatibility complex antigen expression by murine recombinant interferon-gamma. 308 10

In this study, we analyzed the effect of tumor necrosis factor (TNF) on retinoic acid (RA)-induced myeloid differentiation of the promyelocytic HL-60 leukemia cell line. We show that low concentrations of the two substances, almost inactive in inducing differentiation when used separately, induce differentiation when added simultaneously to the cell cultures. Cells simultaneously expressing both monocyte/macrophage phenotype (typically induced by TNF) and granulocyte characteristics (typically induced by RA) are induced by a combination of the two factors, indicating that TNF and RA potentiate each other's activity. The results obtained using immune interferon (IFN-gamma) in combination with the two inducers suggest that the mechanism of action of TNF and IFN-gamma are possibly different. The inhibitory effect of RA on the expression of HLA class I antigens and of the high-affinity Fc receptor is potentiated by TNF but completely reversed by rIFN-gamma.
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PMID:Retinoic acid cooperates with tumor necrosis factor and immune interferon in inducing differentiation and growth inhibition of the human promyelocytic leukemic cell line HL-60. 310 17

The tumor promoters 12-O-tetradecanoylphorbol-13-acetate (TPA) and the teleocidins (TCDs) had similar inhibitory effects on IgE binding onto the membrane of rat basophilic leukemia (RBL)-2H3 cells. The level of expression of the functional IgE Fc receptor (Fc epsilon R), as measured by CELISA, was decreased up to a maximum of 60% within 5 min-1 h of treatment. This inhibition was obtained at concentrations of 0.1 microgram/ml for most TCDs, of 1 microgram/ml for TPA and of 20 micrograms/ml for one TCD (olivoretin A). These molecules also decreased the amount of cell-bound IgE detectable by CELISA on cells that had been coated with IgE prior to TCD treatment. When incubated with RBL-2H3 cells for 30 min-2 h, the TCDs and TPA stimulated serotonin release. Depending on their concentration, they had various effects on IgE-plus antigen-induced serotonin release. It is suggested that the down-regulation of IgE receptor expression by these tumor promoters is mediated through protein kinase C activation and phosphorylation of the Fc epsilon R.
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PMID:Protein kinase C activators of the teleocidin family decrease the IgE-binding capacity of rat basophilic leukemia cells. 313 76

A mouse monoclonal antibody raised against acute myeloid leukaemia cells (YB5.B8 monoclonal antibody; Gadd, S. J. and Ashman, L. K. (1985): Leukaemia Res. 9, 1329-1336) has been found by an indirect immunoperoxidase technique to bind to scattered cells in frozen sections from a number of human tissues. They have been identified as mast cells in fixed sections of skin, tonsil and duodenum by simultaneous staining of glycosaminoglycan with Alcian blue in 0.7 N HCl. The antibody does not distinguish mast cells in mucosal tissues from those in connective tissue, although the level of expression by cells at both sites appears to be heterogeneous. With the exception of low affinity binding to B lymphocytes, no other bone marrow-derived cells were found to bind the antibody. In particular, basophils and eosinophils were not stained, suggesting that they are not related closely to mast cells and that the antigen detected by YB5.B8 monoclonal antibody is not an IgE Fc receptor. Therefore, among all mature haemopoietic lineages, the antibody is specific for mast cells.
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PMID:Specificity of a mouse monoclonal antibody raised against acute myeloid leukaemia cells for mast cells in human mucosal and connective tissues. 330 21


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