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

By means of the incorporation rate of 3H thymidine into the lymphocytes of patients with chronic lymphatic leukaemia the possibility of stimulating them by using different mitogens was checked and compared with normal persons. The examination covered 11 patients treated with extracorporeal irradiation of the blood (ECIB), 5 patients treated with a chlorambucil therapy, and 10 untreated patients who were classified according to the staging system proposed by RAI. The lymphocytes of the peripheral blood were stimulated as mixed and isolated T and B-lymphocytes in the microculture by using the mitogens PHA, PWM, ConA, and LPS. In all CLL patients there was a diminished stimulation rate of a mixed lymphocyte population. A relation existed between the seriousness of the stage and the diminution of the incorporation rate of 3H thymidine. A corresponding correlation could not be identified in untreated CLL patients. Isolated T-lymphocytes revealed better results of stimulation than the total population. As to their function B-lymphocytes showed a dependance on the kind of therapy. In the mixed lymphocyte culture of normal persons the best findings could be observed after stimulation with PHA, that is also valid for CLL patients. PHA, PWA, ConA, and LPS were suitable as substances stimulating B-lymphocytes with different efficacy in normal persons and CLL patients. Both collectives showed the best results in the T-lymphocyte culture after stimulation with LPS.
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PMID:[Relationship between the capacity to be stimulated of lymphocyte subpopulations and the RAI staging in patients with chronic lymphocytic leukemia]. 8 87

Purified proteins (Pa-1 and Pa-2) from pokeweed have been compared with commercial pokeweed mitogen (PWM-G) and other mitogens in their ability to stimulate human lymphocytes. With cultures of T and B cells separated from tonsil lymphocytes, thymidine uptake, blast transformation and immunoglobulin (Ig) synthesis have been measured. IgM and IgG was measured in supernates of stimulated cultures by radioimmunoassay. Pa-1, Pa-2 and PWM-G were found to be potent mitogens for unseparated tonsil lymphocytes or nylon column purified T cells. Pa-2 was found to be active at lower concentrations than Pa-1, and PWM-G was less potent than the purified mitogens. These three mitogens all stimulated unseparated lymphocytes to secrete large quantities of Ig (20-100 mug/ml) during 7 days in culture. With increasing amounts of mitogens severe decreases in immunoglobulin synthesis were observed at day 6 even with doses which were still optimal for stimulation of thymidine uptake at days 3 and 6. With purified B cells (less than 2% T cells) Pa-1 was the best mitogen for thymidine incorporation. However, the secretory response was very variable. In some experiments B cells did not secrete Ig in response to mitogens; in others Pa-1 was clearly more effective at stimulating secretion than Pa-2 or PWM-G and in some experiments B cells were stimulated by all three. In one experiment Pa-1 stimulated prolymphocytic leukaemia cells to blast transformation and the secretion of IgM. It is concluded that Pa-1, Pa-2 and PWM-G are much better activators of Ig synthesis in human cultures than either PHA or LPS and that Pa-1 is the most reliable B-cell stimulant of the three.
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PMID:The effects of purified mitogenic proteins (Pa-1 and Pa-2) from pokeweed on human T and B lymphocytes in vitro. 108 10

The number and distribution patterns of lymphocytes in the spleens and lymph nodes of Balb/c mice which express immunoglobulin surface receptors were studied in terms of the effects of a murine leukemia virus on the immune-response mechanism. Friend leukemia virus induces a prompt, marked depression of the immune response of mice to antigens such as sheep erythrocytes and E. coli LPS. A functioning T- and B-lymphocyte system is necessary for the response to the SRBC's whereas E. coli LPS, a T cell-independent antigen, stimulates B cells alone. Although the responses to both classes of antigen were markedly depressed in FLV-infected mice, the major defect appeared to be impairment of B-cell function, at least early in the course of infection. In order to examine in more detail the mechanism of interaction between FLV and lymphoid cells with Ig surface receptors, presumably B cells, immmunofluorescent analyses were performed with spleen, and lymph node cells from FLV-infected mice. Within a few days after infection there was a marked decrease in the percentage of spleen cells with Ig surface molecules, although the absolute number of these cells was either unchanged or increased due to marked splenomegaly caused by the virus. A marked decrease in the percentage of splenocytes with theta antigen, considered a marker for mature T cells, also was evident in infected mice. The number of spleen cells showing evidence of FLV infection (i.e., positive for FLV-associated antigens) increased rapidly during the first few days after infection, and within 2 to 2 1/2 weeks nearly all of the nucleated splenocytes were positive for the tumor antigen. In contrast to the results for spleen cells, there were increases rather than decreases in the percentages of Ig-positive and theta-positive cells in the lymph nodes after infection. The number of lymph-node cells that showed the presence of FLV antigen was much lower than in the spleen, and their appearance was also much slower as the leukemic process progressed. Despite these differences between spleen and lymph-node cells in terms of relative percentages of Ig- and theta-positive lymphocytes, relatively similar depressions were evident for the percentages of lymphoid cells that could redistribute their surface Ig receptors into polar caps when incubated with anti-Ig serum at 37 C. Marked impairment of the Ig-capping responses for both spleen and lymph-node cells paralleled the course of infection and development of immunosuppression. These observations indicate that murine leukemia virus infection can both alter the responsiveness of immunocompetent cells to T-dependent and independent antigens and depress the number and normal functional activity of these cells, as reflected by altered surface Ig receptors and antigens.
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PMID:Lymphocyte surface receptors and leukemia virus-induced immunosuppression. 109 86

LP-BM5 murine leukemia virus (MuLV) induces an immunodeficiency syndrome (MAIDS) in C57BL/6 mice which resembles immunological abnormalities observed in early stages of human AIDS. In our study, MAIDS virus-infected mice were exposed to low doses of ultraviolet radiation (UVR) before and after virus inoculation and compared with MAIDS-infected but not UVR-exposed mice. In all tested parameters (blood IgM levels; mitogenic responses to PHA, ConA, LPS and anti-mu; MLR; antigenic response to SRBC; enlargement and histopathologic changes of the spleen) we observed the same trend: changes due to MAIDS infection were more pronounced in the UVR-exposed group than in the unexposed group. Statistically significant differences between these two groups were seen for mitogenic responses at two different time points after virus inoculation. These results demonstrate that in vivo UVR exposure enhances the immunosuppressive effects of a retroviral infection. UVR exposure may affect the progression of AIDS in a similar manner.
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PMID:In vivo exposure to ultraviolet radiation enhances pathogenic effects of murine leukemia virus, LP-BM5, in murine acquired immunodeficiency syndrome. 133 87

The IgE-dependent activation of mononuclear phagocytic cells through their capacity to express low affinity IgE receptors (Fc epsilon RII) has been proposed as a mechanism for the development of airways inflammation in allergic asthma. This Fc epsilon RII expression leads to the IgE-dependent production of the potent pro-inflammatory cytokines IL-1 beta and TNF-alpha. Expression by monocytes of Fc epsilon RII is regulated by several cytokines including interleukin-4, gamma- and alpha-interferons, and granulocyte-macrophage and macrophage colony stimulating factors. An anti-inflammatory effect of nedocromil on monocytes has been proposed as a possible mechanism for its anti-asthma activity. We therefore investigated the capacity of nedocromil to modulate mononuclear phagocyte Fc epsilon RII expression and cytokine production. We used an anti-Fc epsilon RII antibody and flow cytometric analysis to assess the capacity of nedocromil to modulate cytokine-induced Fc epsilon RII expression in normals and asthmatics. Monocytes, THP-1 monocyte leukaemia cells, and alveolar macrophages were exposed to varying concentrations of these cytokines for 48 hr at 37 degrees C with or without the additional presence of nedocromil (1-10 microM) and the per cent of monocytes expressing Fc epsilon RII was determined. No changes in Fc epsilon RII expression were observed. Subsequently, we investigated the capacity of nedocromil to affect the capacity of IgE plus anti-IgE complexes, allergen, and LPS (16 hr/37 degrees C) to stimulate IL-1 beta and IL-6 production. No changes were observed when nedocromil was applied concomitant with the stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anti-inflammatory effects of nedocromil sodium: inhibition of alveolar macrophage function. 133 83

A cDNA corresponding to a serum gp70 synthesized as an acute phase protein in mouse hepatocytes was cloned and analyzed. This cloned cDNA had the characteristics of an endogenous xenotropic murine leukemia virus. Synthesized oligo-DNA specific for this cDNA reacted strongly with liver RNA derived from NZB mice injected with LPS as a trigger of an acute phase inflammatory response. There was also low level of gp70 in the kidney in response to LPS injection. The LTR structure of the cDNA showed that this clone is the immediate precursor of an infectious xenotropic virus in the proposed evolutionary scheme of murine leukemia virus.
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PMID:Expression and structure of serum gp70 as an acute phase protein in NZB mice. 137 41

The role of elevated intracellular calcium concentration [Ca2+]i in the LPS-induced activation of interleukin-1 beta (IL-1 beta) production was examined in cells representing different stages of myeloid differentiation (undifferentiated monocytic leukaemia cell line THP-1, THP-1 cells induced to adherent, macrophage-like cells by phorbol ester treatment and normal peripheral blood-derived adherent monocytes). LPS did not elevate the [Ca2+]i as measured by the Fura-2 fluorescence technique. When these cells were stimulated with LPS in the presence of the calcium ionophore A23187, a clear increase in the IL-1 beta protein production was observed in the undifferentiated THP-1 cells but not in the more differentiated cell types. This ionophore-induced increase was also seen in the IL-1 beta mRNA levels. Thus these data confirm the previous findings demonstrating that elevation of [Ca2+]i is not involved in the LPS-dependent signal transmission. However, the LPS-induced signals are greatly potentiated by the elevated [Ca2+]i, but only in undifferentiated monocytic cells.
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PMID:The effect of calcium mobilization on LPS-induced IL-1 beta production depends on the differentiation stage of the monocytes/macrophages. 138 20

Post-transfusional hepatitis is often a complication in patients with acute myelogenous leukemia (AML) in whom survival is paradoxically prolonged. The etiology is unknown. In previous studies, we showed that impaired hepatic endotoxin (lipopolysaccharide, LPS) clearance in patients with acute viral hepatitis A, B, or C versus controls results in endotoxemia and tumor necrosis factor alpha (TNF-alpha) release. TNF-alpha mediates anti-proliferative and differentiating effects in AML cell lines. Interferon-gamma (IFN-gamma) released in acute viral hepatitis, acts in synergy with TNF-alpha. HL60, KG1, and U937 AML cells treated 3, 6, and 9 days with physiologically attainable TNF-alpha (10 U/ml), IFN-gamma (100 U/ml) and LPS (10 ng/ml) levels, have significantly diminished viability and cell growth versus controls. Treatment of HL60 AML cells with LPS/TNF-alpha/IFN-gamma also resulted in significantly increased monocytic pathway differentiation not seen with KG1 or U937 AML cells. HL60 AML cells treated with TNF-alpha/IFN-gamma for 6 days released endogenous TNF-alpha (1.57 U/10(6) cells) upon LPS stimulation compared to less than 0.01 U/10(6) cells in non-LPS-stimulated TNF-alpha/IFN-gamma-treated cells or untreated cells (p less than 0.0001). Untreated HL60 AML cells co-cultured with HL60 cells pretreated for 6 days with TNF-alpha/IFN-gamma and then subjected to LPS stimulation had significantly diminished cell growth compared to controls (p less than 0.0001). This effect could be reversed with anti-TNF-alpha antibody, supporting the concept that endogenous TNF-alpha release by LPS/TNF-alpha/IFN-gamma treated HL60 AML cells may act by paracrine means to suppress growth of other AML cells. The beneficial effects of post-transfusional hepatitis in AML patients may be mediated via LPS/TNF-alpha/IFN-gamma-induced AML cell growth suppression and/or terminal differentiation in which AML cells participate by releasing TNF-alpha after being acted upon by LPS/TNF-alpha/IFN-gamma. Endogenously released TNF-alpha might then act by autocrine/paracrine means to mediate further suppression and terminal differentiation.
Leukemia 1992 Oct
PMID:Beneficial effects of post-transfusional hepatitis in acute myelogenous leukemia may be mediated by lipopolysaccharides, tumor necrosis factor alpha and interferon gamma. 140 56

1. The effect of n-alcohols (methanol and ethanol) and anesthetics (lidocaine, thiopental, methohexital and thiamylal) on procoagulant activity (PCA) in human peripheral-blood monocytes and non-adherent cultured leukemia promonocytic U937 and THP-1 cells was examined herein. 2. Exposure of whole blood to ethanol showed no effect on PCA in human monocytes. However, ethanol dose-dependently inhibited LPS-induced PCA in isolated human monocytes. 3. In THP-1 cells, ethanol had no significant effect on PCA in either non-challenged or LPS-induced status. However, the induction of PCA by LPS was substantially inhibited when cells were pretreated with 1% ethanol (v/v) for 72 hr. 4. In U937 cells, n-alcohols and anesthetics resulted in dose-dependent depressions in PCA. Importantly, the percent reduction in LPS-induced PCA was much more pronounced than that in non-challenged PCA. 5. These data clearly suggest that n-alcohols and anesthetics readily inhibit the LPS-stimulatory action on monocytic PCA.
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PMID:Inhibition of endotoxin-induced monocytic procoagulant activity by n-alcohols and anesthetics. 168 19

CD5, a pan-T cell antigen, is expressed on a minor subset of normal B lymphocytes and on cells of most B lineage tumors or transformed B cells in both man and animal models. In the present study, the effects of various humoral factors on CD5 expression by cells of a subcloned 70Z/3 murine pre-B leukemia cell line were investigated. Among the humoral factors studied, only LPS up-regulated CD5 expression on 70Z/3 cells (three- to fourfold) in a dose-dependent manner. However, this up-regulatory effect of LPS was not observed when cells were cultured in serum-free medium. NZB-serum factor (NZB-SF), a cytokine we have identified and shown to enhance the maturation and proliferation of immature B cells, synergistically enhanced CD5 expression in the presence of suboptimal doses of LPS. IL-4 down-regulated CD5 expression by 70Z/3 cells induced by LPS or LPS plus NZB-SF in a dose-dependent manner. IL-4 also suppressed spontaneous CD5 expression by 70Z/3 cells. No other cytokine tested showed an inhibitory effect. LPS, IFN-gamma, NZB-SF, and IL-1 enhanced sIg expression on 70Z/3 cells and their action on sIg expression was not inhibited by IL-4. Thus, the down-regulatory action of IL-4 on CD5 expression appeared specific for this antigen. IFN-gamma, which inhibits IL-4 induced CD23 and DR expression on B cells, does not abolish the down-regulatory action of IL-4 on CD5 expression by 70Z/3 cells. Changes in mRNA levels on coding CD5 were also examined following the incubation of 70Z/3 cells (24 hr) in the presence of humoral factors which can influence CD5 Ag expression. The levels of mRNA for CD5 Ag were moderately increased in the presence of LPS and NZB-SF. IL-4 appeared to suppress the actions of NZB-SF and LPS at least in part by reducing the levels of mRNA encoding CD5.
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PMID:Up-regulation and down-regulation of cell surface and mRNA expression of CD5 antigen by various humoral factors on murine 70Z/3 pre-B cell leukemia cell line: IL-4 down-regulates CD5 antigen expression. 169 87


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