U937 cell line: impact of CSFs, IL-6 and IFN-gamma on the differentiation and the Leu-CAM proteins expression.

Differentiation of the U937 cell line can be induced by various agents. We have investigated the differentiation abilities of gamma-interferon (IFN-gamma), interleukin-6 (IL-6), macrophage and granulocyte-macrophage colony-stimulating factors (M-CSF + GM-CSF) or the combinations IL-6 + M-CSF + GM-CSF and IFN-gamma + M-CSF + GM-CSF on the U937 cells by studying the morphology, cytochemical activity and several functional properties. The expression of the Leu-CAM proteins (CD11a, CD11b, CD11c, CD18) was also evaluated during the culture period. Our results show that the cytokines used in this study inhibit to a certain extent the proliferation of the tumor cells and drive the cells toward a differentiation phenotype that has several characteristics in common with mononuclear phagocytes, such as the expression of CD14, phagocytosis and release of superoxide anions. The adhesion molecules CD11b alpha chain and CD18 beta chain were strongly induced on the U937 cells with a maximal expression of the CD11b on the cells cultured with either M-CSF + GM-CSF or the combinations of IL-6 and IFN-gamma with M-CSF + GM-CSF. Conversely, for CD11a and CD11c alpha chains a rather low enhancement of the expression was noticed. In our culture system, cells incubated with the combination of M-CSF + GM-CSF exhibited differentiation characteristics which appeared to be largely potentialized when cytokines such as IL-6 or IFN-gamma were added.

Human blood-derived macrophages: differentiation in vitro of a large quantity of cells in serum-free medium.

Large quantities of human blood-derived monocytes have been cultured in suspension in nonadherent cell culture bags and maintained for up to 3 weeks in a serum-free medium. This serum-free medium contained Iscove's modified Dulbecco's medium (IMDM) supplemented with human albumin, alpha-phosphatidylcholine, transferrin, and insulin. Morphology, cell surface antigens, and functional properties of these in vitro maturing macrophages were studied in comparison with macrophages cultured in a standard medium containing 10% fetal calf serum. In this report we demonstrate that this serum-free medium allows a better yield of cell survival than the standard medium; it also allows the differentiation of blood monocytes into fully functional macrophagic cells that express the different antigens found in mature macrophages. The results indicate that the use of serum-free defined medium offers good conditions in which to culture large numbers of human monocytes and allows an accurate analysis of the effect of supplementation with growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF) on the differentiation and survival of monocytes and macrophages. Serum-free cultures could also be helpful for the precise analysis of the cell secretion activity and for determining the factors that are responsible for monocyte maturation into macrophages.

Long term cultures of human monocytes in vitro. Impact of GM-CSF on survival and differentiation.

In vitro differentiation of human monocytes (Mo) provides large amounts of mature and functionally competent macrophages (M phi) which may be used as potentially powerful anticancer agents for adoptive immunotherapy. Granulocyte macrophage-colony stimulating factor (GM-CSF) was evaluated for its ability to influence long term cultures of Mo-derived M phi. Large quantities of Mo isolated by leukapheresis and elutriation were cultured in non-adherent cell culture bags or in plastic flasks with or without GM-CSF. At various stages of differentiation, GM-CSF treated M phi were recovered and assayed for survival, morphology, surface antigens, functional properties and proliferation in comparison with control M phi. In the present paper, we demonstrate that GM-CSF at a concentration of 50 U/ml (5 ng/ml) promotes better cell survival and the differentiation of Mo into M phi displaying certain morphological differences as compared to control M phi such as an increased expression of Max-1 antigen, CR3 and Fc gamma II receptors, higher phagocytic properties and increased capacities of cytotoxicity and TNF secretion when the cells are further activated by IFN-gamma. Furthermore, GM-CSF treated cells exhibit a low-grade proliferation although the nature of the proliferating cells has not been entirely elucidated. We conclude that the GM-CSF treated M phi would be particularly suitable for adoptive immunotherapy.

Large scale isolation of human blood monocytes by continuous flow centrifugation leukapheresis and counterflow centrifugation elutriation for adoptive cellular immunotherapy in cancer patients.

The increasing interest in mononuclear phagocytes for adoptive cellular immunotherapy (ACI) trials in cancer patients led us to define a procedural approach to harvest reproducibly highly purified single-cell suspensions of large numbers of functional human circulating blood monocytes (Mo). A semiclosed counterflow centrifugal elutriation (CCE) system has been developed, using a new large capacity Beckman JE 5.0 rotor with one interchangeable 40 ml or 5 ml separation chamber, to purify Mo from mononuclear cell (MNC) concentrates of healthy donors and cancer patients obtained by continuous flow centrifugation leukapheresis (CFCL). This method does not require a Ficoll density gradient centrifugation step. A total of 115 leukapheresis procedures were carried out in 35 patients and in 30 healthy donors by either Cobe 2997 or Cobe Spectra, with a similar efficiency in MNC apheresis. The average yield per leukapheresis procedure was 5.6 x 10(9) MNC of purity 90-100% (25-45% Mo, 40-65% lymphocytes). The average yields per elutriation procedure (R/O fraction) were 1.1 x 10(9) cells (purity 93% Mo) using the 5 ml separation chamber, and 1.5 x 10(9) cells (purity 91%) using the 40 ml separation chamber, with a respective recovery of 82 +/- 7% and 78 +/- 8% Mo. In vitro analysis of the viability and function of the purified Mo shows that neither morphological integrity nor physiological activity was compromised by this two-step isolation procedure, which additionally provides highly purified human Mo suspensions, in a quantity suitable for ACl of cancer patients.

Apheresis-elutriation program for adoptive immunotherapy with autologous activated monocytes in cancer patients.

Human blood monocytes (Mo) and monocyte-derived macrophages (M phi) are known to be potent antitumor cytotoxic effector cells through activation with recombinant human interferon gamma (rIFN-gamma), bacterial muramyldipeptide or the synthetic derivative muramyltripeptide phosphatidylethanolamine entrapped in liposomes (L-MTP-PE). Large-scale generation of ex vivo activated Mo from the blood of cancer patients proved feasible. We report our experience with a fixed rotor speed counterflow centrifugation elutration (CEE) procedure using the newly available Beckman high capacity JE-5.0 rotor system that reproducibly isolates up to 1.0-1.5 x 10(9) Mo with greater than 90% purity, in suspension and functionally intact derived from peripheral blood mononuclear cell-enriched suspensions obtained by leukapheresis (LP) from healthy volunteers and cancer patients. The semiclosed, easy to handle CCE system, was adapted to a sterile technique that permitted clinical trials in adoptive monocyte immunotherapy. Freshly isolated Mo did not lose morphological or functional integrity and had no spontaneous activation. Their abilities to become activated to the cytotoxic state after 18-h stimulation with 500 U/ml rIFN-gamma or 1 microgram/ml L-MTP-PE and to differentiate into matured M phi in vitro were not altered. The system was therefore used to isolate large numbers of Mo for a phase I clinical trial of intraperitoneal immunotherapy with L-MTP-PE activated autologous Mo in nine patients with peritoneal carcinomatosis. Each patient received weekly Mo infusions (n = 5) with an intrapatient dose escalation schedule (from 10(7) to 10(9) Mo). Toxicities were mild including fever, chills and abdominal pain. There was no treatment-induced thromboembolic event or capillary leak syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute myeloid leukaemia with 8p11 (MYST3) rearrangement: an integrated cytologic, cytogenetic and molecular study by the groupe francophone de cytogénétique hématologique.

Thirty cases of acute myeloid leukaemia (AML) with MYST histone acetyltransferase 3 (MYST3) rearrangement were collected in a retrospective study from 14 centres in France and Belgium. The mean age at diagnosis was 59.4 years and 67% of the patients were females. Most cases (77%) were secondary to solid cancer (57%), haematological malignancy (35%) or both (8%), and appeared 25 months after the primary disease. Clinically, cutaneous localization and disseminated intravascular coagulation were present in 30 and 40% of the cases, respectively. AMLs were myelomonocytic (7%) or monocytic (93%), with erythrophagocytosis (75%) and cytoplasmic vacuoles (75%). Immunophenotype showed no particularity compared with monocytic leukaemia without MYST3 abnormality. Twenty-eight cases carried t(8;16)(p11;p13) with MYST3-CREBBP fusion, one case carried a variant t(8;22)(p11;q13) and one case carried a t(8;19)(p11;q13). Type I (MYST3 exon 16-CREBBP exon 3) was the most frequent MYST3-CREBBP fusion transcript (65%). MYST3 rearrangement was associated with a poor prognosis, as 50% of patients deceased during the first 10 months. All those particular clinical, cytologic, cytogenetic, molecular and prognostic characteristics of AML with MYST3 rearrangement may have allowed an individualization into the World Health Organization classification.

Synthesis of complement components C2 and C4 by human monocyte-derived macrophages during in vitro differentiation in serum-free culture conditions.

In order to analyze the kinetics of complement component synthesis by human monocytes/macrophages, we have developed a system of defined culture conditions in the absence of serum. Moreover, the use of the polymerase chain reaction (PCR) provides a high sensitivity for the detection of mRNAs and the study of the regulation of complement component synthesis by these cells. Human blood monocytes were collected and purified by cytapheresis and elutriation, and then cultured in nonadherent cell culture bags for up to 3 weeks. Cells were grown in Iscove's modified Dulbecco's medium supplemented with alpha-phosphatidylcholine, transferrin, insulin, glutamine and antibiotics. The phenotypic and functional properties of macrophages differentiated under these serum-free culture conditions have been previously analyzed [1]. Secretion of complement component was measured by a hemolytic assay. mRNA was prepared using guanidine isothiocyanate extraction followed by cesium gradient ultra-centrifugation. cDNA was obtained by reverse transcription, then amplified by PCR. Fresh monocytes did not display any secretion of C2 as measured by hemolytic assay. However, C2 secretion was detected on and after the 3rd day of serum-free cultured unstimulated monocytes. The rate of C2 production increased along with macrophage differentiation up to the 3rd week of culture. We were not able to detect any functional C4 secretion. In preliminary studies, C2 and C4 mRNAs were detected in macrophages and in unstimulated fresh monocytes. These preliminary studies show that the serum-free culture conditions we have developed allow very satisfactory survival and differentiation of human monocytes, and provide optimal conditions for the study of their secretory activity.

Human resident peritoneal macrophages: phenotype and biology.

Macrophages represent the primary line of host defences in the peritoneal cavity. In order to study the metabolic activity and maturation stage of human resident peritoneal macrophages (PM phi). peritoneal fluid (PF) was taken by Douglas puncture from healthy hyperstimulated infertile women undergoing oocyte retrieval for in vitro fertilization. Peritoneal fluid and macrophage culture fluids were studied for different inflammatory mediators such as interleukin-1 (IL-1), tumour necrosis factor (TNF) and interleukin-6 (IL-6). The level of macrophage colony-stimulating factor (M-CSF), which represents a macrophage proliferation and differentiation factor, was determined in the PF and in the serum. Furthermore, the macrophage phenotypic profile was analysed, in particular the expression of sex steroid hormone receptors. IL-1. IL-6 and TNF were detectable in the PF and in the culture supernatants of PM phi whether stimulated or not by IFN-gamma and LPS. The mean level of M-CSF in the PF was 6.37 +/- 2.02 ng/ml as measured by RIA; this level did not correlate with the concentration of PM phi. The mean PF-M-CSF level was 1.4-fold higher than in the sera as measured by a EIA. Oestrogen and progesterone receptors could not be demonstrated on the PM phi analysed, so that a direct relationship between the ovarian steroid concentration in these women and the function of PM phi was unlikely. As compared to peripheral blood monocytes (Mo). PM phi showed a phenotypic profile, with some more mature features, e.g. increased expression of CD14, CD68, FcRII, FcRIII, CR3, CR4 and MHC class II determinants. These results indicate that resident PM phi have acquired in vivo a certain differentiation and/or activation state under micro-environmental factors where cytokines secreted by the M phi themselves or by other cells such as the mesothelium may play important roles.

Immunophenotypic characterisation of human peritoneal and alveolar macrophages and of human blood monocytes differentiated in the presence of either GM-CSF or M-CSF or a combination of GM-CSF/M-CSF.

In vivo, circulating blood monocytes (Mo) migrate into the various tissues where they undergo terminal maturation into macrophages (M phi) with morphological and sometimes functional properties that are characteristic for the tissue in which they reside. This tissue-specific M phi heterogeneity results from the immediate microenvironment, but may also originate from genetically distinct Mo subpopulations. The in vitro transformation of Mo to M phi is thought to reflect the events of the in vivo maturation and thus is widely used as a model to analyse M phi development. To study the heterogeneity within the mononuclear phagocyte system, we have investigated the phenotypic characterisation of mature tissue M phi, blood Mo and Mo-derived M phi cultured in medium with either GM-CSF, M-CSF or a combination of both cytokines. Tissue peritoneal and alveolar M phi showed different antigenic specificities, particularly concerning the transferrin receptor and CD68 and CD14 antigens. M-CSF-derived M phi when compared to the other M ø populations also exhibited a significantly increased expression of transferrin receptor and CD68 antigen. In contrast, GM-CSF treated cells which exhibited a better long term survival, showed notably more positivity for CD11b and CD32 antigens. These results show that the phenotypic heterogeneity of the different M phi populations is limited and appears to result from discrepancies in the differentiation and/or activation of the cells. The location of the CD68 antigen, which is generally considered to be an intracellular protein, was investigated at the ultrastructural level and found to be exclusively situated at the outer cell membrane.