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Biomedical subjects

B Klein

Publications and source records attributed to B Klein.

At least 145 records · Page 8Linked to original sources
PubMed1995

Interleukin-10 is a proliferation factor but not a differentiation factor for human myeloma cells.

Because interleukin-10 (IL-10) is a potent differentiation factor of human B cells into mature plasma cells, we investigated its effect on human malignant plasma cells. IL-10 did not induce any differentiation and increase in Ig synthesis in four human IL-6-dependent malignant plasma cell lines. However, it stimulated the proliferation of two of four cytokine-dependent cell lines in the absence of IL-6 and IL-10-dependent myeloma cell lines have been obtained. The myeloma cell growth activity of IL-10 was unaffected by anti-IL-6 and anti-IL-6R antibodies. Similarly, IL-10 stimulated (P = .001) the proliferation of freshly-explanted myeloma cells in IL-6-deprived cultures of tumor samples from patients with active multiple myeloma (MM) and produced twice as many myeloma cells in these cultures. Again, this cytokine was unable to induce further differentiation (assessed by rate of Ig production) of fresh myeloma cells. A very sensitive enzyme-linked immunosorbent assay (ELISA; 1 pg/mL) only rarely detected IL-10 in the sera of MM patients (3 of 89). On the contrary, serum IL-10 was detected in 60% of patients with plasma cell leukemia (12 of 20). These data show that IL-10 is an IL-6-unrelated growth factor for malignant plasmablastic cells. This cytokine could be involved in the late phase of MM in vivo.

Cell Differentiation↗
PubMed1995

Potent interleukin 3 receptor agonist with selectively enhanced hematopoietic activity relative to recombinant human interleukin 3.

A systematic evaluation of structure-activity information led to the construction of genetically engineered interleukin 3 (IL-3) receptor agonists (synthokines) with enhanced hematopoietic potency. SC-55494, the most extensively characterized member of this series, exhibits 10- to 20-fold greater biological activity than recombinant human IL-3 (rhIL-3) in human hematopoietic cell proliferation and marrow colony-forming-unit assays. In contrast, SC-55494 is only twice as active as rhIL-3 in priming the synthesis of inflammatory mediators such as leukotriene C4 and triggering the release of histamine from peripheral blood leukocytes. The enhanced hematopoietic activity of SC-55494 correlates with a 60-fold increase in IL-3 alpha-subunit binding affinity and a 20-fold greater affinity for binding to alpha/beta receptor complexes on intact cells relative to rhIL-3. SC-55494 demonstrates a 5- to 10-fold enhanced hematopoietic response relative to its ability to activate the priming and release of inflammatory mediators. Therefore, SC-55494 may ameliorate the myeloablation of cancer therapeutic regimens while minimizing dose-limiting inflammatory side effects.

Amino Acid Sequence↗
PubMed1995

Pharmacokinetic study of anti-interleukin-6 (IL-6) therapy with monoclonal antibodies: enhancement of IL-6 clearance by cocktails of anti-IL-6 antibodies.

The use of inhibiting cytokine-binding-proteins (CBPs) such as soluble cytokine receptors and anticytokine antibodies is considered for the treatment of cytokine-dependent diseases. The pleiotropic cytokine interleukin-6 (IL-6) is a target for immunointervention in numerous pathologic situations, including multiple myeloma, B-cell lymphoma, and rheumatoid arthritis. An antitumor response was obtained in the treatment of a patient with multiple myeloma. A controversial issue is to evaluate whether the carrier effect of the CBPs might limit their efficiency in blocking the target cytokine. We analyzed the pharmacokinetics of radiolabeled IL-6 in mice treated with various combinations of anti-IL-6 antibodies. We show that injection of one or two antibodies led to the stabilization of the cytokine. Conversely, simultaneous treatment with three anti-IL-6 antibodies, binding to three distinct epitopes, induced the rapid uptake of the trimeric immune complexes by the liver and the elimination of IL-6 from the central compartment. The use of cocktails of three antibodies binding simultaneously to a cytokine thus provides a new means of enhancing the clearance of the target molecule and should help in the design of antibody-based clinical trials by overcoming the problem of the accumulation of the cytokine in the form of monomeric immune complexes.

Animals↗
PubMed1995

Interleukin-6 signal transducer gp130 has specific binding sites for different cytokines as determined by antagonistic and agonistic anti-gp130 monoclonal antibodies.

The cytokines interleukin (IL)-6, IL-11, ciliary neurotrophic factor (CNTF), leukemia inhibitor factor (LIF), oncostatin M (OSM) and probably the recently cloned cytokine cardiotrophin-1, signal, in combination with their specific receptors, through the common signal transducer gp130. Here, we report that the signaling activities of IL-6, IL-11, CNTF and OSM/LIF can be specifically blocked by different anti-gp130 monoclonal antibodies (mAb). Furthermore, we found two mAb, B-P8 and B-S12, which directly activate gp130 independently of the presence of cytokines or their receptors. This agonistic activity includes induction of cytokine-dependent cell proliferation and stimulation of acute-phase protein synthesis in liver cells. Compared to B-P8 mAb, the B-S12 mAb exhibited the strongest agonistic activity, while both mAb are synergistic in their action. This activity could not be blocked by inhibiting mAb against IL-6 and the IL-6 receptor. In contrast to F(ab')2 of B-S12 which still could activate gp130, Fab fragments completely lost their agonistic activity. Activation by tyrosine phosphorylation of the transcription factors Stat1 and APRF/Stat3 was also induced by B-S12 and B-P8, suggesting that both mAb induce homodimerization of gp130. Since hematopoietic stem cells express gp130 on their plasma membrane, it was anticipated that the agonistic anti-gp130 mAb could stimulate the proliferation of these stem cells. Indeed, B-S12 and B-P8 were able to stimulate CD34+ cells. In summary, our data show for the first time that mAb against gp130 can specifically block the action of distinct IL-6-type cytokines that signal through gp130. Such mAb might be of great value for therapeutic applications in diseases where a single cytokine action needs to be inhibited. In addition, the agonistic gp130 mAb may be used as growth factors for maintenance and expansion of stem cells prior to grafting.

Animals↗
PubMed1995

Cytokine-binding proteins: stimulating antagonists.

Cytokine-binding proteins (CBPs) block the ability of cytokines to interact with their receptors. These agents can potentially provide a means of treating pathological conditions that have a significant cytokine involvement. However, a major drawback of such approaches relates to the fact that CBPs stabilize the cytokine in the form of a cytokine-CBP complex in vivo. Here, Bernard Klein and Hervé Brailly discuss the possibility that CBPs behave either as agonists or antagonists according to their pharmacokinetic characteristics in vivo, and suggest a mechanism by which stable complexes might be cleared from the system.

Animals↗
PubMed1995

Immunomodulating IL-6 activity by murine monoclonal antibodies.

The human anti-mouse immunoglobulin antibody (HAMA) response, which occurs frequently after injection of murine monoclonal antibodies (MAb) directed against cellular targets, has been reported extensively in several studies. We analysed here HAMA in 12 patients (six with multiple myeloma, MM, and six with metastatic renal cell carcinoma, MRCC) who were treated with B-E8, an IgG1 MAb against interleukin-6 (IL-6). Efficiency of the treatment was evidenced by the drop in the serum levels of C reactive protein (CRP), of which the in vivo production is under the control of IL-6. Three patients with MM and the six patients with MRCC became immunized to the injected MAb. HAMA appeared between days 7 and 15 after the beginning of the treatment. The nine patients made IgG antibodies; four also made IgM. All of immunized patients made anti-idiotype antibodies specific to B-E8. Two of them also developed HAMA directed to murine IgG1 isotype; in these two patients B-E8 MAb cleared rapidly from the circulation with loss of treatment efficiency. In the patients who developed only anti-idiotype antibodies, serum levels of B-E8 remained unchanged and CRP production remained inhibited, indicating that treatment efficiency was not affected by the presence of HAMA. Circulating B-E8 MAb were still able to bind to IL-6 and to inhibit IL-6-independent proliferation despite the presence of anti-idiotypic HAMA. Therefore, in contrast to HAMA against MAb directed against cellular targets, HAMA against anti-IL-6 MAb idiotopes led neither to clearance nor to functional inactivation of the injected MAb.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1995

Assessment of the nucleolar organizer regions by automated image analysis in benign and malignant colonic tumours and adjacent tissues in rats.

An automated computer image analysis technique was used to study the morphological parameters of argyrophilic nucleolar organizer regions (AgNORs) in chemically induced rat colonic tumours of different grades. Different nuclear parameters were of different diagnostic value. For distinguishing tumorous tissue from normal tissue all the parameters studied were capable of serving as diagnostic markers. Malignant processes could, however, be more reliably detected by means of the area of the nucleus, nuclear shape factor, area of AgNOR and ratio of AgNOR area to nuclear area. In macroscopically normal tissue adjacent to a tumour, the values of all the AgNOR parameters studied were similar to those in tumorous tissues. It can be concluded that the initial stages in tumorigenesis are accompanied by changes in all of the nucleus and AgNOR parameters, but as malignancy develops, only some of these parameters continue to change. Close correlations between nuclear parameters in malignant tissue suggest that for diagnostic purposes only nuclear and AgNOR areas should be used.

Adenocarcinoma↗
PubMed1995

Acid mucin and high molecular weight cytokeratin in prostatic lesions: evaluation of a combined histochemical and immunohistochemical stain.

OBJECTIVE: To evaluate the presence of acid mucins and high molecular weight cytokeratin (KER) in prostatic lesions using a combined histochemical and immunohistochemical stain consisting of Alcian blue at pH 2.5(AB) with a strept-avidin-biotin complex (SAB) staining for KER (SAB-KER). MATERIALS AND METHODS: Sections were obtained from archival paraffin blocks which included 20 cases of prostatic carcinoma, 30 cases of benign hyperplasia, and five cases of basal cell hyperplasia. Sections were stained for mucosubstances using the AB stain, for KER using SAB-KER and by both AB and SAB-KER, the combined stain (CS). RESULTS: With the CS stain KER, which is present in the prostatic basal cells, was not detected in malignant glands and in 60% of these cases intraluminal blue-stained acidic mucin was seen. On the other hand, all benign hyperplastic prostatic glands were devoid of intraluminal acidic mucin and showed staining for KER of their basal cells. Areas of basal cell hyperplasia were strongly positive for KER and intraluminal acidic mucin was seen in one case. Each of the stains separately gave similar results to the CS method but the contrast between the areas of carcinoma and hyperplasia was accentuated by the CS, and small foci of carcinoma were easily detected. CONCLUSION: The combined AB+SAB-KER stain is quicker to perform and allows the simultaneous appraisal of acid mucin and KER.

Avidin↗
PubMed1995

The significance of soluble interleukin-2, soluble interleukin-2 receptors, soluble ICAM-1 and beta 2-microglobulin in breast cancer patients.

The serum levels of soluble interleukin-2 (sIL-2), sIL-2 receptors (sIL-2R), beta 2-microglobulin (beta 2M) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured by the ELISA technique in 129 breast cancer patients and 40 controls. The median serum levels of sIL2-R, beta 2M and sICAM-1 were significantly higher and sIL-2 significantly lower than controls. sIL-2R, sICAM-1 and beta 2M levels were significantly higher in patients with metastatic disease compared to patients on long-term follow-up with no active disease. Initial study measurements of these markers could not identify patients at high risk for relapse. These findings suggest that the sIL-2R level is indicative of metastatic disease and together with other parameters of immune activation may be of help in monitoring disease activity in breast cancer patients.

Adult↗
PubMed1995

An interleukin 1 receptor antagonist blocks the IL-1-induced IL-6 paracrine production through a prostaglandin E2-related mechanism in multiple myeloma.

By analogy with the model of pristane-induced mouse plasmacytomas, we have wondered about the putative role of prostaglandin E2 (PGE2) in the human multiple myeloma (MM) cytokine network, involving interleukin 6 (IL-6) and interleukin 1 (IL-1) as essential myeloma cell growth factors and inducing cofactors respectively. We show that PGE2 is produced in short-term cultures of bone marrow cells of patients with MM, concomitantly with both IL-6 and IL-1. Indomethacin, a potent inhibitor of cyclo-oxygenase and of PGE2 synthesis, significantly inhibits IL-6 production (but not IL-1 production) by 35% to 90% depending on the different MM patients studied and concurrently to that of PGE2. Exogenous PGE2 reverses this inhibition or even stimulates IL-6 production. An IL-1 receptor antagonist (IL-1RA) also significantly inhibits PGE2, IL-6 production and myeloma cell growth. The inhibition of IL-6 production is reversed by adding exogenous PGE2. These results show that induction of IL-6 by IL-1 is related to PGE2 in the bone marrow of patients with MM. Inhibition of PGE2 synthesis (as obtained with indomethacin and the IL-1RA) might be helpful to inhibit myeloma cell proliferation by reducing IL-1-induced endogenous IL-6 production not only in vitro (as demonstrated here) but also in vivo.

Animals↗
PubMed1994

A highly sensitive quantitative bioassay for human interleukin-11.

Human interleukin-11 (IL-11) is a cytokine with a broad spectrum of activity, similar to interleukin-6 (IL-6). However, its role in human disease is poorly understood, partly because of a lack of sensitive bioassays. A subclone (B9-11) obtained from the B9 hybridoma (which responds poorly to human IL-11) enabled us to develop a highly sensitive bioassay for human IL-11. B9-11 cells responded only to human IL-11 and IL-6 and not to other human cytokines using the same gp130 transducer chain (ciliary neurotrophic factor, leukemia inhibitory factor and oncostatin M) or to other human interleukins (interleukin-1 to interleukin-13), human hematopoietic cytokines (granulocyte colony stimulating factor, granulocyte-macrophage colony stimulating factor, colony stimulating factor-1) and various other human cytokines (interferon-alpha, tumor necrosis factor-alpha, tumor necrosis factor-beta, fibroblast growth factor and nerve growth factor). In addition, these cytokines did not interfere with the IL-11 response of B9-11 cells. IL-11-induced proliferation of B9-11 cells was unaffected by anti-murine IL-6 receptor mAb but inhibited by anti-gp130 mAb. Half-maximal proliferation of B9-11 cells was obtained with 30 pg/ml of recombinant IL-11, a concentration 300-fold lower than IL-11 concentrations known to be active on human cells. Finally, culturing of B9-11 cells with an anti-IL-6 mAb enabled us to measure the natural IL-11 produced by various cell lines. Thus, B9-11 cells should be useful for studies of IL-11 involvement in various human diseases as well as for a better understanding of the mechanisms of action of this cytokine.

Animals↗
PubMed1994

Reproducible obtaining of human myeloma cell lines as a model for tumor stem cell study in human multiple myeloma.

We report a novel, reproducible methodology which enabled 10 human myeloma cell lines (HMCL) to be obtained from each of 10 tumor samples harvested from 9 patients with extramedullary proliferation. Fresh samples were cultured with interleukin 6 (IL-6) and granulocyte macrophage-colony stimulating factor (GM-CSF) at a high cell density and resulting HMCL growth became progressively dependent on IL-6 alone, no longer requiring GM-CSF. These HMCL, which had the same immunoglobulin gene rearrangements as the patients' original myeloma cells, were designated XG-1 to XG-9. XG HMCL had a plasma cell morphology, expressed plasma cell antigen (Ag), namely cytoplasmic immunoglobulins, CD38, B-B4 Ag, and CD77, and lacked the usual B-cell Ag. They also expressed activation antigens such as CD28 with coexpression of CD28 and its ligand, B7 Ag, in four HMCL. Six HMCL expressed CD40, 4 CD23, and 5 its ligand, CD21. The XG HMCL bore adhesion molecules VLA-4 and CD44 (all 10 HMCL), VLA-5 (7 HMCL), and CD56 (4 HMCL). Finally, cytogenetic study of 8 HMCL indicated a 14q+ chromosome, and t(11,14) translocation was found in 6 of 8 and 5 of 8 HMCL, respectively. The possibility of obtaining malignant plasma cell lines reproducibly from each patient with extramedullary proliferation offers a unique tool for studying the phenotype and abnormalities of the still unidentified tumor stem cell in this disease.

Cell Division↗
PubMed1994

Rearrangement of CCND1 (BCL1/PRAD1) 3' untranslated region in mantle-cell lymphomas and t(11q13)-associated leukemias.

Rearrangement and overexpression of CCND1 (BCL1/PRAD1), a member of the cyclin G1 gene family, are consistent features of t(11q13)-bearing B-lymphoid tumors (particularly mantle-cell lymphoma [MCL]). Its deregulation is thought to perturb the G1-S transition of the cell cycle and thereby to contribute to tumor development. As suggested by previously published studies, rearrangement of the 3' untranslated region (3' UTR) of CCND1 may contribute to its activation in some lymphoid tumors. To define further the prevalence of such rearrangements, we report here the result of the molecular study of 34 MCL and six t(11q13)-associated leukemias using a set of probes specific to the different parts of the CCND1 transcript. We also sequenced the entire cDNA of the overexpressed CCND1 transcripts in a t(11q13)-associated leukemia. DNA from four of these 40 patients showed rearrangement of the 3' UTR of CCND1 coexisting with major translocation cluster (MTC) rearrangement. Southern blot and sequence analyses showed that, as a result of these rearrangements, the 3' AU-rich region containing sequences involved in mRNA stability and in translational control is eliminated. Moreover, the finding that the CCND1 mRNA half-life was greater than 3 hours (normal tissues, 0.5 hours) in three t(11q13)-associated cell lines stresses the importance of posttranscriptional derangement in the activation of CCND1. Finally, we did not observe any mutation in the coding frame of the CCND1 cDNA analyzed.

Amino Acid Sequence↗
PubMed1994

Survival of UV-irradiated vaccinia virus in normal and xeroderma pigmentosum fibroblasts; evidence for repair of UV-damaged viral DNA.

Vaccinia virus replicates in the cytoplasm of cells from a large number of vertebrates and is independent of most or all cellular enzymes and factors needed for DNA replication and gene transcription. To investigate whether vaccinia virus is also independent of nucleotide excision-repair enzymes present in the nucleus, we have investigated the host-cell reactivation of UV-irradiated virus in normal human fibroblasts and fibroblasts from various xeroderma pigmentosum (XP) complementation groups (A, C, D, G and XP-variant). It was found that the survival of UV-damaged vaccinia virus is the same in the normal and all UV-sensitive cell strains tested, suggesting it is independent of host-cell excision-repair enzymes. This agrees with results of Lytle et al. (1972), but is in conflict with data from Závadová (1971). The D37 of vaccinia virus survival is approximately 7 J/m2 in all cells tested, indicating that in normal cells vaccinia virus is very sensitive to ultraviolet light. We also found that cyclobutane pyrimidine dimers disappear from parental viral DNA strands, suggesting that vaccinia DNA is subject to some form of DNA repair. The implications of these results are discussed.

Animals↗
PubMed1994

Molecular analysis of the IL-6 receptor in human multiple myeloma, an IL-6-related disease.

A PCR-SSCP approach was used to search for mutations in IL-6 receptor genes in 9 human plasma cell lines (HMCL) and in tumor plasma cells from 19 patients with fulminating multiple myeloma, an IL-6-related disease. Whereas no mutation was found in the cytokine receptor homologous (CRH) domain of IL-6R alpha, DNA and RNA polymorphisms in the gp130 CRH domain was detected in tumoral samples as well as in blood samples from healthy donors. Finally, mutations in the gp130 critical cytoplasmic domain were found in one HMCL and in tumor plasma cells of one patient. Only the mutated allele was expressed in the HMCL.

Antigens, CD↗