Search PubMed⌕ Search

Biomedical subjects

E G Bamberger

Publications and source records attributed to E G Bamberger.

18 recordsLinked to original sources
PubMed2001

Simultaneous flow cytometric measurement of K-562 megakaryocytic differentiation and CD56+ large granular lymphocyte cytotoxicity.

K-562 cells have the capacity to undergo multi-lineage differentiation, which may be crucial to their ability to serve as target reservoirs for CD56+ large granular lymphocytes (LGL). Conventional techniques using chromium release assays to measure lymphocyte-mediated cytotoxicity suffer from disadvantages, including radioactive contamination and the inability to simultaneously determine K-562 and/or CD56+ lymphocyte phenotypes. We illustrate here a three-color flow cytometric method providing for the simultaneous evaluation of K-562-CD56+ LGL binding, K-562 cell viability, and the status of K-562 cell differentiation. Phorbol 12-myristate 13-acetate (PMA) engenders megakaryocytic differentiation in K-562 cell populations, as measured by presentation of the beta(3) integrin (gpIIIa, CD61), while maintaining a negative expression of MHC-I and MHC-II molecules. Using the auto-fluorescence of K-562 cells, flow cytometry can be used to demonstrate a significant decrease in CD56+ LGL activity against K-562 cells in populations pre-incubated with PMA. The capacity of three-color flow cytometry to measure lymphocyte-target cell binding and cell death kinetics, while simultaneously determining target cell phenotype, permits the specific localization of CD61-expressing K-562 cells to areas inconsistent with CD56+ LGL-mediated patterns of lysis.

Antigens, CD↗
PubMed2000

PMA-treated K-562 leukemia cells mediate a TH2-specific expansion of CD4+ T cells in vitro.

Highly enriched preparations of human CD3+CD4+ T-lymphocytes were stimulated with mitogen or OKT3 to determine the capacity of K-562 cells to function as accessory cells. Phorbol 12-myristate 13-acetate (PMA)-treated K-562 cells were induced to differentiate along the megakaryocytic lineage and could supplant monocyte-accessory cell function. Intracytoplasmic analysis of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) established that IL-4, and not IFN-gamma, was preferentially produced by the activated lymphocytes. This polarized stimulation is compatible with a type 2 or humoral immune response of purified T cells co-cultured with differentiated K-562 cells in vitro, and may have implications in immunoregulation due to disease progression.

CD3 Complex↗
PubMed1998

Differential regulation of interleukin-1alpha and interleukin-1beta in K-562 cells.

Interleukin (IL)-1alpha and IL-1beta are encoded by two separate genes, but both function as comitogens for lymphocyte activation. In this study, we observed K-562 cells to express constitutively mRNA for IL-1alpha, although IL-1alpha was not detected in the growth-conditioned medium (GCM). However, IL-1beta mRNA was not expressed unless the cells had been treated with phorbol myristate acetate (PMA). Both IL-1alpha and IL-1beta were detected in the GCM after the cells had been cultured with PMA, suggesting that IL-1 elaboration required PMA treatment. The K-562 cells treated with PMA differentiated to the myeloblastic stage, as observed by nuclear morphologic properties by electron microscopy. PMA treatment induced de novo expression of CD61 or gpIIIa, a marker associated with megakaryoblasts. These results showed that although K-562 cells constitutively expressed IL-1alpha mRNA, PMA treatment was required for secretion. On the other hand, both the expression and secretion of IL-1beta required treatment with PMA. This study showed that K-562 cells treated with PMA differentiated to the myeloblastic stage and expressed and secreted IL-1alpha and IL-1beta.

Cell Division↗
PubMed1988

Lowered susceptibility of K-562 cells treated with gamma interferon in serum-free medium to natural killer cell-mediated cytolysis.

K-562 cells grown in serum-free medium were treated with gamma interferon (IFN-gamma) and they became significantly less susceptible to natural killer (NK) cell-mediated cytolysis. To examine if this loss in susceptibility was related to induced differentiation events, the presence of various antigens was determined after induction. There was a coincident expression of class I HLA common antigen, although it is not clear if this is a direct causal relationship. The level of the constitutively expressed myelomonocytic antigen, reactive with anti-Leu-M1, was not affected by IFN-gamma induction and three normally nonexpressed monocytic antigens, defined by monoclonal antibodies, remained unexpressed. IFN-gamma did induce an enhanced expression of IL-2 receptors on K-562 cells after 2 days of treatment but, thereafter, the expression appeared to be suppressed. Electron microscopy of IFN-gamma-treated cells revealed the development of increased surface blebbing and electron-dense cytoplasmic inclusions. These ultramicroscopic changes could not be correlated with definitive differentiation events. We suggest that IFN-gamma treatment of K-562 cells induces class I HLA expression and morphological changes that may be important to differentiation events that render the cells less susceptible ot NK-mediated cytolysis.

Cell Differentiation↗
PubMed1987

Continuous or modulation expression of hematopoietic cell antigens in sublines of the leukemia cell line, K-562.

K-562 is described as a pluripotent leukemic cell line which expresses a diversity of hematopoietic cell differentiation antigens. With the use of monoclonal antibodies (MoAb), we show that the expression of these antigens is either "modulated", i.e. they are not expressed in early logarithmic growth but are expressed in late logarithmic growth, or "continuous", i.e. they are not affected by proliferation and phase of culture growth. Whether an antigen is modulated or continuously expressed appears to be an inherent property of the subline, since the expression of myeloid antigen binding the MoAb, PM81, was modulated on cells from a clone, whereas, the expression of this antigen was continuous by the parent subline and an independent subline F-1. Continuously expressed antigens appear to be an integral component of the K-562 cell surface matrix, while modulated antigen expression appears to be influenced by culture growth conditions.

Antibodies, Monoclonal↗
PubMed1987

Interferon-gamma-induced expression of class I HLA antigens on K-562 cells grown in serum-free medium.

Human interferon-gamma (IFN-gamma), encoded in Escherichia coli by recombinant human DNA, induces the expression of HLA antigens in the pluripotent hematopoietic stem cell line K-562 grown in serum-free growth medium. Expression was noted in 90% of the cells within 4 days and there was a high density of expression per cell, as determined by cytofluorography. Upon subculture, the cells rapidly lose their ability to express HLA, indicating that the continued presence of IFN-gamma is necessary for the expression. Reinduction of expression with IFN-gamma occurs in a high percentage of cells (up to 90%), which is comparable to the induction in freshly treated control cells.

Cell Line↗
PubMed1986

Diversity of cell surface hematopoietic antigens on K-562 sublines identified with monoclonal antibodies.

The surface antigen profile of 8 sublines of K-562 cells, the original line, and the clone RA6 was determined with a panel of 12 monoclonal antibodies reactive with hematopoietic cell differentiation antigens. Cells from all sublines expressed the precursor hematopoietic antigen reactive with RFB-1, the T-cell antigen reactive with OKT17, the B cell/granulocyte antigen reactive with BA-1, the My-1 antigen, and glycophorin A which reacted with R10. A low percentage of cells in some of the sublines expressed platelet/monocyte glycoprotein I binding AN51, monocyte antigen binding 63D3, and an erythroblast/monocyte/platelet antigen binding 5F1. The use of a panel of K-562 sublines demonstrates that K-562 cells do share several "common" antigens but express a marked diversity and variability of other hematopoietic antigens.

Antibodies, Monoclonal↗
PubMed1985

Natural killer cell resistance in K-562 cell sublines.

Sublines of the hematopoietic stem cell line K-562 were tested for their susceptibility to human natural killer (NK) cell activity. A correlation was found between the degree of NK-mediated lysis and the presence or absence of particular chromosomal markers. K-562 subline susceptible to lysis by NK were found to express karyotypically a deletion 9- and a marker 8(t1-18), whereas resistant sublines did not express these markers. A cloned K-562 subline B1V was chosen as representative of a resistant subline. This subline was resistant to lysis even after prolonged incubation and activation of the NK cells with interferon. However, it was found that B1V was lysed by both antibody-dependent, complement-mediated and antibody-dependent cellular mechanisms at levels comparable to those seen with NK-sensitive K-562 sublines. Subline B1V did compete poorly with NK-sensitive K-562 in cold-target inhibition; however, conjugate-formation assays demonstrated that the binding of NK cells to B1V cells is comparable to that of NK-sensitive K-562 cells. We suggest that cells of the cloned line B1V are recognized normally by NK cells but do not activate the lytic mechanism of the bound NK cell. Treatment of the resistant clone B1V with neuraminidase did not lead to enhanced levels of lysis. Protein extracts of NK-sensitive K-562 sublines efficiently inhibited lysis by NK cells but extracts of the resistant clone, B1V, did not inhibit lysis, suggesting that the clone lacks cell surface determinants involved in the post-recognitive activation of the NK cytolytic mechanism.

Cell Line↗
PubMed1982

Antibody lysis of human hematopoietic cells in the absence of complement and effector cells.

The incubation of K-562 leukemia cells with specific goat immunoglobulin resulted in gradual cytolysis in the absence of complement and effector cells. Optimal lysis (100%), reached in 3-4 days, occurred when the concentration of the antibody in the culture medium was about 20 micrograms/ml containing an initial inoculum of 15,000 cells. A lower concentration (10 micrograms/15,000 cells/ml) led to partial cytolysis; the surviving cells, cultured in fresh medium, were still vulnerable to antibody lysis (30 micrograms/ml), thus indicating the lack of an apparent resistant cell population. The amount of free antibody in the culture medium diminished rapidly and very little or none was detectable after 2-3 hours of incubation with K-562 cells. The immune gamma-globulin also inhibited colony formation of K-562 cells in soft agar. The immune gamma-globulin, absorbed extensively with normal blood cells, to pluripotent K-562 cells, cross-reacted with several human malignant hematopoietic cell lines tested. These cells included T-lymphoblasts (JM and MOLT-4), promyelocytes (HL-60), Burkitt's lymphoma cells (RAJI), myeloblasts (KG-1 and KG-1a), and multiple myeloma cells (K-737). The absorption of the immune gamma-globulin with an equal number of cells from each of the cell lines assayed diminished but did not completely remove the antibody responsible for cytolysis of K-562 target cells. Thus, the K-562 leukemia blasts appear to possess common and specific antigens that may be only partially expressed on other committed leukemia cell lines studied. For this reason, the cytolytic activity of the immune gamma-globulin could only be removed by absorption with K-562 cells possessing a complete array of antigens solely present on pluripotential hematopoietic cells.

Antibodies↗
PubMed1981

Induction of hemoglobin synthesis in original K 562 cell line.

Cells of the original human myelogenous leukemia cell line, K 562 were induced to synthesize hemoglobin by incubation with 0.05 mM hemin. Analysis by isoelectric focusing indicated major bands in the region of hemoglobin F, Bart's hemoglobin, and embryonics. Cytochemical analysis by the Lepehene peroxidase reaction for hemoglobin indicated an heterogeneous population of cells with respect to hemoglobin induction. Approximately 50% of the cells were positive for hemoglobin. The benzidine-positive material was present as granules in the region of the Golgi apparatus of large blasts with undifferentiated nuclei. There was no indication of normal maturation or of terminal differentiation into reticulocytes or erythrocytes.

Cell Line↗
PubMed1978

Cytotoxicity of a factor from normal and abnormal human spleens for allogenic leukemia cells.

A search for an endogenous cytotoxic factor (ECF) was made by analyzing 103 spleens from normal humans and patients suffering from hematopoietic malignancies, solid tumors, inflammatory diseases, and congestive and hyperplastic splenomegalies. A highly purified ECG was obtained by a combination of gel filtration and ion-exchange column chromatography. The factor is a low-molecular-weight (less than 2,000) substance and is probably a peptide or peptide-nucleotide complex. The biologic activity of EC was assayed on myelogenous and lymphatic leukemia cells of human origin. The spleens from normal individuals produced and/or stored the largest quantity of the ECF. The amount of ECF extractable from the pathologic spleen was drastically diminished regardless of the disease or therapeutic regimen. The ECF was significantly more cytotoxic for lymphatic than for myelogenous leukemia cells.

Anemia↗
PubMed1977

Hematopoiesis in hereditarily athymic mice.

Hematopoiesis was studied in hereditarily athymic (nude) mice and athymic mice given congeneic thymus cells. Athymic and reconstituted mice had mild anemia which resulted from both hypoplasia of the bone marrow erythrocytic series and decreased iron incorporation in erythroid precursors. Untreated nude mice had hypoplastic marrows due to decrease of both erythrocytic and lymphocytic precursors. The latter was associated with a marked peripheral lymphopenia. Transplantation of thymocytes caused the number of bone marrow and peripheral lymphocytes to return to normal whereas the granulocytic series decreased. Mice reconstituted with thymocytes had marked neutrophilia, eosinophila, and monocytosis compared with either normal or athymic siblings. The number of granulocytic colonies produced by bone marrow cells in agar was very similar in normal and athymic mice with neutrophilia, thus reflecting a normal functioning granulocytic series in a marrow with decreased lymphocytic and erythrocytic cells. The transplantation of thymocytes into athymic mice had no effect on the number of colonies produced by bone marrow cells and the number of spleen colony forming units. It was postulated that maturation of the additional thymocytes permits them to interact with the few endogenous thymocyte precursors present in the nude mice for promotion of bone marrow erythrocytic and lymphocytic proliferations. Alternatively, mature thymocytes may produce factors that were responsible for the effect on lymphoid and erythroid cells.

Animals↗
PubMed1976

Absence of thymus-derived lymphocyte markers in myelogenous leukemia (Ph1+) cell line K-562.

The myelogenous leukemia cell line K-562 with a Ph1+chromosome, derived from a patient with chronic myelogenous leukemia in terminal blastic crisis, is not a bone marrow-derived lymphoblastic cell line, because the cells neither produce immunoglobulins nor possess complement receptors. Since it has been suspected that blasts found in some patients with chronic myelogenous leukemia in blastic crisis might be thymus-derived cells, we have studied several parameters to demonstrate that K-562 cells are not thymus-derived lymphoblasts. The results of this study show: (a) no cross-reactivity of antisera to K-562 cells with normal human thymocytes; (b) lack of cytotoxicity of a specific horse anti-human thymocyte globulin for K-562 cells; (c) failure of the treatment of K-562 cells with bovine thymosin to induce antigenic determinant and erythrocyte rosette receptors on K-562 cells; (d) presence of receptors for the Fc portion of immunoglobulin G; (e) absence of terminal deoxynucleotidyl transferase; and (f) cytotoxicity of monkey antiserum to K-562 cells for malignant thymus-derived cells (Molt-4). However, absorption with Molt-4 cells abolished the cross-reactivity with Molt-4 cells, whereas 60% of the antibody to K-562 cells remained in the immune serum. Studies of DNA polymerase activities revealed that K-562 cells have levels of polymerase alpha and beta, like other proliferating cells, and an RNA-dependent DNA polymerase activity, presumably representing polymerase gamma.

Antigens, Neoplasm↗