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S Funderud

Publications and source records attributed to S Funderud.

At least 73 records · Page 4Linked to original sources
PubMed1986

Distinct effect of forskolin and interferon-gamma on cell proliferation and regulation of histocompatibility antigen expression in hematopoietic cells.

The adenylate cyclase activator, forskolin, was found to induce expression of class I and class II major histocompatibility complex antigens in a B precursor cell line, Reh, as well as in a B lymphoid cell line, Raji. No such effect was, however, observed when the promyelocytic cells line HL-60 was treated with either forskolin or the cAMP analogue 8-bromoadenosine cyclic monophosphate. As expected, all three cell lines showed reduced proliferation upon forskolin treatment. Forskolin induced expression of class I and class II major histocompatibility complex antigens in cell lines not affected by interferon-gamma and vice versa, indicating that cAMP is not involved in the regulation of histocompatibility antigens by interferon-gamma. We also compared the effect of interferon-gamma and 12-O-tetradecanoylphorbol 13-acetate on major histocompatibility complex class I and class II expression, and despite differences in the response on the tested cell lines, we can not at this point exclude the possibility that protein kinase C is involved in the action of interferon-gamma.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1986

Internalization and processing of antibodies to surface antigens on human B cells. Monoclonal anti-IgM antibodies are processed differently than monoclonal antibodies towards non-Ig surface receptors.

The internalization and intracellular processing of monoclonal antibody to immunoglobulin mu heavy chain (Mamu) have been investigated in two human Burkitt lymphoma cell lines (Ramos and Raji), in a human B cell lymphoma and in normal human peripheral blood B cells. In addition to the degradation of 125I-labeled Mamu to trichloroacetic acid (TCA) soluble material, a distinct pattern of larger 125I-Mamu fragments was detected in all sources of B cells tested. The particular fragmentation pattern, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis, involved the cleavage of both peptide bonds and disulfide bridges. This type of antibody fragmentation appeared to be a selective mechanism associated with sIgM, as no other degradation than that leading to TCA-soluble material could be detected after the internalization and degradation of radiolabeled monoclonal antibodies towards a variety of non-Ig B cell surface receptors. Three fragments of 125I-Mamu degradation were also detected in the supernatant of Ramos cells, implying that the recycling and exocytosis of certain 125I-Mamu fragments also took place.

Antibodies, Monoclonal↗
PubMed1986

The interaction between cell-surface antigens and antibodies bound to monodisperse polymer particles in normal and malignant cells.

The interaction between polymer particles with an immune ligand on their surfaces and normal (hepatocytes) and malignant (Raji) cells with a corresponding membrane receptor was investigated by scanning and transmission electron microscopy. The influence of time, temperature, and anti-metabolites on this process was studied. The results indicate that when particles with an immunoligand are added to cells with a corresponding membrane receptor, three successive steps are initiated, the first two of which are not dependent on the temperature or the metabolic state of the cells. The first step in this process is the binding of particles to the cell surface through the immunoligand on the particle and the receptor on the cell surface. The initial binding formed by immunoligand and corresponding receptor is followed by a stronger interaction between cell and particle. This second step seems to be governed by a successive antibody-antigen interaction: the zipper mechanism. A third step in the particle-to-cell interaction is characterized by movements of the cellular surface, as revealed by membrane folds, pseudopods, and lamellae extending from the surface and enveloping large parts of the particle.

Antigen-Antibody Reactions↗
PubMed1986

Characterization of human mononuclear cells after positive selection with immunomagnetic particles.

We have investigated the possibility to employing magnetic monodisperse polymer particles for positive selection of human peripheral blood mononuclear cell populations. By carefully titrating the ratio between particles and cells we succeeded in isolating a number of cell populations that could be cultivated subsequently in vitro for functional studies. The success of the procedure is partly dependent on the properties of the monoclonal antibodies used to sensitize the cells. Provided these antibodies do not react with membrane structures involved in the transduction of activating signals, highly purified, quiescent cell populations can be recovered in a single fractionation step. In most instances particles will detach from the isolated cells by overnight culture, and the particles can then be removed from the system by a suitable magnet. T lymphocytes, subpopulations of T lymphocytes, and B lymphocytes have been isolated in this way and studied in a variety of functional assay systems. Comparison with cells obtained after negative selection clearly demonstrates the usefulness of this technique, especially if the membrane marker selected for it is not directly engaged in the activation processes.

Antibodies, Anti-Idiotypic↗
PubMed1986

HLA class I and II typing using cells positively selected from blood by immunomagnetic isolation--a fast and reliable technique.

This paper describes a new cell isolation and HLA typing technique, which permits cell separation and HLA class I or class II typing to be performed in 70 min. Magnetic monodisperse microspheres (Dynabeads TM) were coated with monoclonal antibodies (MAbs) specific for the CD8 T cell antigen or for HLA class II monomorphic epitopes. They could then be used to obtain HLA class I or class II positive cells directly from ACD blood in approximately 15 min by the use of magnetic separation. The cells (attached to the microspheres) were subsequently used in microcytotoxic HLA typing (total incubation time of 55 min) using acridin orange/ethidiumbromide to stain viable (yellow) and dead (red) cells. It was found that this immunomagnetic (IM) HLA typing technique was specific, has a sensitivity superior to that observed for conventional microcytotoxicity assays and gave low background staining. IM HLA-ABC typing of 50 healthy donors and 10 patients and IM HLA-DR typing of 25 healthy donors and 30 patients gave results corresponding well with that obtained independently by conventional HLA typing (concordancy rates 92-100%). Furthermore, the IM HLA typing technique permitted reliable HLA class II typing of blood cells from six patients where conventional HLA class II typing was impossible. The IM HLA typing technique also enables HLA class I and II typing to be quickly and reliably performed on cells from ACD blood of cadaveric donors.

Antibodies, Monoclonal↗
PubMed1985

Antibodies to surface IgM and IgD increase the expression of various class II antigens on human B cells.

Antibodies to surface IgM and IgD were found to induce increased expression of class II antigens on normal and neoplastic human B cells within 24 h of stimulation. Antigens associated with different class II sub-locus genes (DC, DR and SB) were all found to be increased as determined by monoclonal antibodies (Leu-10 and B 3/4 for DC, D 1/12 for DR and MHM4 for SB-associated antigens). The increased expression of class II antigens was selective as anti-immunoglobulins failed to increase expression of other surface antigens such as B1 and beta 2-microglobulin. The effect of anti-mu and anti-delta could be blocked specifically by corresponding myeloma proteins suggesting that antibodies to surface IgM and IgD, respectively, were responsible for the effect observed. Moreover, antibodies to another surface antigen (B1) failed to induce such changes. Increased class II antigen expression appeared to be dependent on protein synthesis, and early changes in ion fluxes, but could not be elicited by membrane depolarization as reported in murine systems.

Antibodies, Anti-Idiotypic↗
PubMed1985

The specific induction of myc protooncogene expression in normal human B cells is not a sufficient event for acquisition of competence to proliferate.

Resting human B cells can be activated to proliferate in the presence of both polyclonal antibodies to immunoglobulin mu heavy chains and B-cell growth factor (BCGF). This process appears to be temporally controlled in that the initial activation of the B cells and their responsiveness to BCGF is carried out by polyclonal anti-mu-chain antibodies alone. We have used this system to investigate the role of the c-myc gene in the cell cycle of normal human peripheral blood B cells. Our results show that the polyclonal anti-mu-chain antibody-induced B-cell activation is accompanied by a specific induction of c-myc gene expression without promoting subsequent entry into the S phase unless BCGF is added. Monoclonal antibodies to either mu chain or the pan-B-cell antigen Bp35 also revealed a similar G0-to-G1 transition and activation of c-myc gene expression. However, unlike activation with polyclonal anti-mu-chain antibodies, cells stimulated with these monoclonal antibodies do not acquire responsiveness to BCGF. The results imply that additional inducible functions must be present to potentiate the myc-specific function in order for the B cells to acquire the capacity to proliferate in response to BCGF. These findings are discussed in relation to the origin of B-cell malignancies.

Antibodies, Anti-Idiotypic↗
PubMed1985

Characterization of two murine monoclonal antibodies reactive with human B cells. Their use in a high-yield, high-purity method for isolation of B cells and utilization of such cells in an assay for B-cell stimulating factor.

We describe two monoclonal antibodies, HH1 and HH2. Both reacted selectively with surface immunoglobulin (sIg)-positive human B cells. Both antibodies stained on average 7-8% of peripheral blood mononuclear cells. They have not been found to react with cells or cell lines of other haematopoietic cell lineages, except that HH2 was positive on a small percentage of cells of the erythroid cell line K562. The molecular weight of the HH1 antigen was 95 kD, as established by Western blotting. Neither of these two antibodies reacted with Ig determinants, Fc receptors, complement receptors, or known class-I or class-II molecules. A combination of these antibodies was used in a direct panning technique for high-yield enrichment of normal B lymphocytes from peripheral blood. The enriched B cells could be further purified by lysis of T cells (final yield, on average 72 +/- 8% of initial B cells) or by a second panning (yield, 35 +/- 11%). The purified B cells contained less than 1% contaminating T cells and less than 0.5% monocytes and were used in an assay for B-cell-stimulating factor which they showed a normal and very reproducible proliferative response.

Animals↗
PubMed1985

Distinct effects of gamma interferon on human B-lymphocyte precursor cell lines.

The effect of gamma interferon (IFN-gamma) on proliferation and antigenic characteristics of cell lines belonging to the B-cell progenitor compartment was studied. We observed a selective effect of recombinant IFN-gamma but not IFN-alpha on proliferation of the B-precursor cell lines Reh and KM3. On day 4, after addition of 400 mu/ml IFN-gamma the [3H]thymidine uptake in these cells was reduced to 60% and 45% respectively, while no effect of IFN-gamma was evident on the proliferation of the more mature B-cell lines Raji, Ramos, B85, and Daudi. On the other hand, both Reh and Ramos showed induction of major histocompatibility complex (MHC) class I antigen expression in response to 400 mu/ml IFN-gamma. In contrast to 12-O-tetradecanoyl-phorbol-13-acetate (TPA), IFN-gamma did not induce increased MHC class II antigen expression on Reh cells. Taken together, our results indicate that IFN-gamma fulfils distinct functions at different levels in the development of B cells.

B-Lymphocytes↗
PubMed1985

Differences in modifications of cytoplasmic free Ca2+ concentration and 86Rb+ influx in human neoplastic B cells by antibodies to mu- relative to delta-Ig heavy chains.

Cytoplasmic free Ca2+ concentration and influx of 86Rb+ (K+ analogue) were determined during the first minutes after stimulation of neoplastic human B cells and B cell lines by antibodies to surface Ig. The Ca2+ concentration increased in the great majority of samples (41 of 48). All of four B cell lines also responded, providing formal evidence that accessory cells are not required for this early, surface Ig-mediated event. Antibodies to delta as well as mu, heavy chains (anti-delta and anti-mu) could induce both Ca2+ and 86Rb+ responses. 86Rb+ responders were found within the group of Ca2+ responders, but no quantitative relation was observed between the two responses. In cells expressing both sIgM and sIgD, antibodies to delta heavy chains were more potent than those to mu heavy chains in inducing Ca2+ responses, whereas the opposite pattern was seen with regard to 86Rb+ responses. These results demonstrate that sIgM and sIgD can deliver different biochemical signals to the cell.

Antibodies, Neoplasm↗
PubMed1984

Transferrin receptor and B-lymphoblast antigen--their relationship to DNA synthesis, histology and survival in B-cell lymphomas.

The reactivity of two monoclonal antibodies identifying antigens related to B-cell activation, B3/25 (the transferrin receptor) and BB-I (the B-lymphoblast-I-antigen), was examined on cell suspensions from 75 cases of monoclonal B-cell lymphomas. The expression of B3/25 antigen was correlated to DNA synthesis as measured by spontaneous 3H-thymidine incorporation (p = 0.0003) and histopathologically high-grade malignancy (p = 0.00003). Furthermore, B3/25 expression was associated with survival since the patients with B3/25-negative tumors survived longer than those with B3/25-positive tumors (p = 0.018). B3/25 expression also defined a larger group of patients with shorter survival than did histopathology alone, 28 cases versus 16 cases, respectively. On the other hand, the BB-I antigen did not reveal an association with DNA synthesis, high-grade malignancy or survival. However, the findings indicated that BB-I may be related to B-cell maturation/differentiation.

Antibodies, Monoclonal↗
PubMed1984

The great majority of childhood lymphoblastic leukaemias are identified by monoclonal antibodies as neoplasias of the B-cell progenitor compartment.

36 acute leukaemias in children, 24 lymphoblastic and 14 myelogenous, have been examined with a set of 10 monoclonal antibodies by indirect fluorescent staining. In the lymphoblastic group the leukaemic cells of 4 children were found to have T-cell phenotype, while 19 of the other 20 T-cell phenotype negative cases were found to be positive for the c-ALL antigen. All 20 were negative for surface immunoglobulin as well as cytoplasmic mu-heavy chains. However, 17 (85%) reacted positively with the monoclonal antibody AB-1 which we have developed against a B-cell lymphoma, thus revealing B-lineage specificity. Another B-lineage-associated antibody (AB-2) reacted with 8/20 (40%) of the cases with distribution similar to B-1. These findings suggest that the great majority of non-T-non-B acute lymphoblastic leukaemias are neoplasms derived from the B-cell progenitor compartment. Moreover, monoclonal antibody testing allows further sub-categorization in this group. Similarly the acute-myelogenous leukaemia group could be subdivided into phenotypic subsets. The importance of using panels of monoclonal antibodies in the diagnosis of acute leukaemias is discussed.

Adolescent↗
PubMed1983

Delineation of subsets in human B-cell lymphomas by a set of monoclonal antibodies raised against B lymphoma cells.

Murine hybridoma antibodies to a human B-cell lymphoma were developed. After screening against normal T cells, monocytes, and granulocytes 11 antibodies that reacted with cells from other B-cell lymphomas remained, of which 10 showed individually distinct staining patterns, as tested by indirect fluorescence. When tested against lymphomas or cell lines, none of these antibodies revealed staining patterns suggesting reactivity with conventional B-cell surface markers, such as immunoglobulin, complement factor 3 receptors, or HLA-DR antigens. Only one of the antibodies (GB1) reacted with human serum, as determined by a blocking assay. The antibodies were found to belong to different immunoglobulin isotypes. Two antibodies (GB13 and GB14) reacted with greater than 5% of normal peripheral blood mononuclear cells. These reactions were mainly due to reactivity with B cells. The antibodies reacted only in a few cases with acute leukaemias, B-cell lines, and follicular lymphomas. On the other hand, distinct patterns of reactivity in different histological groups of diffuse lymphomas were obtained, suggesting that the antibodies may be useful in delineating phenotypic subsets among human B-cell lymphomas.

Animals↗
PubMed1983

Natural killer cell activity is closely associated with a growth-inhibitory serum protein with protease-like activity.

A correlation between natural killer (NK) cell activity and growth inhibition (GI), as measured in an in vitro assay with B16 melanoma cells, mediated by a serum growth-inhibitory factor (GIF), among various strains of mice has been demonstrated. Beige mice (bg/bg), known to express low NK-activity, were also low in GIF activity and showed increased susceptibility to both B16 melanoma cells and another solid tumor (Lewis lung carcinoma) in vivo. In vivo treatment with various protease inhibitors that reduced NK-activity, also reduced growth inhibition mediated by GIF. Protease inhibitors that did not affect NK-activity did not affect GIF either. All of 4 B16 melanoma clones selected against GIF in vitro and resistant to GIF showed both resistance to NK-cells in vitro and increased growth potential in vivo. However, P-815, an NK-resistant cell line, was sensitive to GIF.

Animals↗
PubMed1983

Triggering of monoclonal human lymphoma B cells with antibodies to IgM heavy chains: differences of response obtained with monoclonal as compared to polyclonal antibodies.

A comparative study of human B lymphoma cells activation by monoclonal (murine hybridoma) antibodies to mu heavy chains (Ma-mu) as compared to polyclonal (rabbit) antibodies to mu heavy chains (Ra-mu) has been carried out. Early events related to calmodulin activation such as 86Rb influx and changes in cell volume at 4 h could be induced by Ma-mu. One antibody (AF6) approached Ra-mu with regard to the strength of response obtained. However, Ma-mus including AF6 were deficient in inducing DNA synthesis under conditions where this was achieved with Ra-mu. Studies in one lymphoma, where stimulation of re-expressed surface IgM could be studied, revealed that Ma-mu was deficient in stimulating re-expressed sIgM. These findings raise questions with regard to polyclonal antibody to surface Ig as a model for B cell triggering by antigen and suggest that antigen-induced B cell triggering may be more complex than indicated by previous studies with polyclonal antibody.

Antibodies, Monoclonal↗
PubMed1983

Purification and characterization of a mouse serum protein with growth inhibitory properties in vitro against tumor cell lines.

A factor which is responsible for the growth inhibitory properties of certain mouse sera and related to NK-activity, has been studied. The factor was isolated from hybrid B6D2F1 (C57Bl/6 x DBA/2) serum, which is histo-compatible with the mouse tumour (B16 melanoma) used and has high NK-activity. Growth inhibitory activity was measured in an in vitro assay. It was independent of complement activation. The responsive factor was isolated and characterized by ion exchange chromatography. Concanavalin A affinity chromatography, gel filtration and iso-electric focusing. It appears to be a protein and had been labelled growth-inhibitory factor (GIF). It has a molecular weight of 230 000-260 000 daltons and an iso-electric point in the pH range 4.6-5.0. It was not retained on Concanavalin A columns.

Animals↗