Identification of osteoclast precursors in multilineage hemopoietic colonies

The osteoclast is known to be derived from the hemopoietic stem cell, but its lineage and the mechanisms by which its differentiation is regulated are largely unknown. There is evidence that osteoclastic differentiation is induced through a contact-dependent interaction between bone marrow stromal cells and hemopoietic precursors. To analyze osteoclastic lineage, colonies were generated in semi-solid medium from mouse spleen cells in the presence of erythropoietin with either Wehi 3B-conditioned medium or interleukin 3 (IL3). After 7 days, individual colonies were picked. Half of each colony was phenotyped by the morphology of cells in cytospin preparations; the second half of each was incubated for 7 days with a bone marrow-derived cell line (ts8) that induces osteoclastic differentiation from hemopoietic cells, on bone slices in the presence of 1,25-dihydroxyvitamin D3. After incubation, bone resorption was assessed by scanning electron microscopy. No resorption was induced in cells derived from single-lineage colonies, but resorptive cells differentiated in 17% of granulocyte-macrophage (GM) colonies and 38% of multilineage colonies. Since only a minority of GM colonies contained osteoclastic precursors, this suggests that the GM colonies that contained osteoclasts were not typical GM colonies but may have been a form of multilineage colony analagous to other multilineage colonies that contain granulocytes, macrophages, and a third cell type. No resorptive cells were formed when IL3-derived colonies were incubated on bone slices without ts8 cells. The results suggest that osteoclasts are derived from a multilineage precursor, upon which IL3 acts to generate cells capable of osteoclastic differentiation, which form resorptive cells upon incubation with bone marrow stromal cells in the presence of 1,25-dihydroxyvitamin D3.     

Growth of diffusion chamber hematopoietic colonies derived from spleen cells of rats administered hydroxyurea.

Donor rats of the Hebrew University strain were administered a single intraperitoneal injection of hydroxyurea (400 mg/kg body weight). 1--3 h following the administration of the drug, a suspension of spleen cells, the majority of which consisted of lymphocytes, was prepared. Spleen cells were placed in diffusion chambers and these were implanted in the peritoneal cavity of preirradiated mice. 5--8 days following implantation, erythroid and granulocytic colonies developed in 30.3% of the diffusion chambers studied. However, in most chambers, macrophages were observed. In control experiments with implantation of spleen cells of normal rats, granulocytic colonies did not grow and in only 3.1% of the chambers erythroid colonies were noted. Macrophage colonies, however, developed in all 32 control cultures. Our previous studies showed that administration of a single dose of hydroxyurea strips the rat bone marrow of approximately 50% of replicating cells within 9--10 h. The results of the present study indicate that such a severe depletion of rat marrow cells results in early committment of spleen stem cells to various blood cell lines.     

Formation of factor-independent hematopoietic multilineage colonies after Abelson virus infection

Yolk-sac-derived hematopoietic cells were infected with a helper-free stock of Abelson virus (A-MuLV). After infection, cells were plated in a clonogenic methylcellulose culture in the absence of exogenous growth factors such as interleukin 3 (IL 3) and erythropoietin (Epo). No colonies were observed in cultures without viral infection, whereas factor-independent colonies were consistently observed with virus- infected cultures. The number of colonies was linearly correlated with the number of cells plated. Erythroid-mix colonies consisting mostly of erythroblasts, macrophages, and mast cells could be observed. Tumorigenic, continuously growing mast cell lines could be generated at high frequency from these erythroid-mix colonies after they were initially passaged in the presence of an irradiated feeder layer for 4 to 8 weeks. Southern blot analysis of the DNA from five of these lines examined were all shown to contain integrated A-MuLV proviral DNA. These data are evidence that A-MuLV can directly infect embryonic multipotent hematopoietic progenitor cells and drive them to differentiate to various progeny cells without exogenous growth factors.     

Sequential generations of hematopoietic colonies derived from single nonlineage-committed CD34+CD38- progenitor cells.

Multiparameter flow cytometry was applied on normal human bone marrow (BM) cells to study the lineage commitment of progenitor cells ie, CD34+ cells. Lineage commitment of the CD34+ cells into the erythroid lineage was assessed by the coexpression of high levels of the CD71 antigen, the myeloid lineage by coexpression of the CD33 antigen and the B-lymphoid lineage by the CD10 antigen. Three color immunofluorescence experiments showed that all CD34+ BM cells that expressed the CD71, CD33, and CD10 antigens, concurrently stained brightly with anti-CD38 monoclonal antibodies (MoAbs). In addition, the CD38 antigen was brightly expressed on early T lymphocytes in human thymus, characterized by CD34, CD5, and CD7 expression. Only 1% of the CD34+ cells, 0.01% of nucleated cells in normal BM, did not express the CD38 antigen. The CD34+, CD38- cell population lacked differentiation markers and were homogeneous primitive blast cells by morphology. In contrast the CD34+, CD38 bright cell populations were heterogeneous in morphology and contained myeloblasts and erythroblasts, as well as lymphoblasts. These features are in agreement with properties expected from putative pluripotent hematopoietic stem cells; indeed, the CD34 antigen density decreased concurrently with increasing CD38 antigen density suggesting an upregulation of the CD38 antigen on differentiation of the CD34+ cells. Further evidence for a strong enrichment of early hematopoietic precursors in the CD34+, CD38- cell fraction was obtained from culture experiments in which CD34+ cell fractions with increasing density of the CD38 antigen were sorted singularly and assayed for blast colony formation. On day 14 of incubation, interleukin-3 (IL-3), IL-6, and GM-CSF, G-CSF, and erythropoietin (Epo) were added in each well. Twenty-five percent of the single sorted cells that expressed CD34 but lacked CD38 antigen gave rise to primitive colonies 28 to 34 days after cell sorting. The ability to form primitive colonies decreased rapidly with increasing density of the CD38 antigen. During 120 days of culture, up to five sequential generations of colonies were obtained after replating of the first-generation primitive colonies. This study provides direct evidence for the existence of a single class of progenitors with extensive proliferative capacity in human BM and provides an experimental approach for their purification, manipulation, and further characterization.     

Reduced tocopherol content of B cells from patients with chronic lymphocytic leukemia

The tocopherol content of lymphocytes, erythrocytes, and plasma from patients with chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), and normal subjects was measured by a sensitive high performance liquid chromatographic method. Lymphocytes from patients with CLL had lower values of tocopherol (1.7 +/- 1.0 micrograms/10(9) cells) than lymphocytes from normal subjects (3.8 +/- 0.7 micrograms/10(9) cells). Mononuclear cells from patients with HCL had an increased tocopherol content of 6.2 +/- 1.0 micrograms/10(9) cells. Subfractionation of the lymphocytes from patients with CLL into T- and B-cell subgroups showed that the tocopherol content of T cells was the same as in normal subjects (4.1 +/- 0.5 micrograms/10(9) cells versus 3.5 +/- 1.2), but that the tocopherol content of the B cells was markedly reduced compared to normals (2.6 +/- 1.0 versus 6.0 +/- 1.3).     

Elevation of IgE-binding factors in serum of patients with B cell- derived chronic lymphocytic leukemia

One hundred nineteen sera from patients with various lymphoproliferative diseases and normal sera were tested by a solid- phase radioimmunoassay (RIA) for their content in IgE-binding factor (IgE-BF), a soluble glycoprotein binding to IgE and derived from low- affinity IgE receptors (Fc epsilon R). Fc epsilon R, recently identified as CD23, are known to be expressed on the surface of B cells at the intermediate stage of differentiation. The results indicate that in all cases of chronic lymphocytic leukemia (CLL) tested (n = 40), IgE- BF levels (45 to 8,656 U/mL) were 3-fold to 500-fold higher than in 24 controls (15.5 +/- 2 U/mL). With a few exceptions, serum IgE-BF levels could differentiate patients with CLL from those with other leukemias or lymphomas. In vitro studies indicated that B lymphocytes isolated from CLL patients produced 8 to 50 times more IgE-BF than did normal B cells (P less than 0.001). IgE-BF level was correlated with the Rai stage of the disease (P = 0.002) and the lymphocyte count (P = 0.041). IgE-BF was purified to homogeneity from one CLL serum sample by a combination of affinity chromatography and reverse-phase high- performance liquid chromatography (HPLC). this IgE-BF proved identical to IgE-BF isolated from the culture supernatant of RPMI 8866 cells, a B lymphoblastoid cell line bearing Fc epsilon R and secreting IgE-BF. Indeed, the two molecules had the same mol wt (25 to 27 kd), the same isoelectric point, and the same tryptic map. We suggest that determination of serum IgE-BF might prove useful for clinical monitoring of CLL.     

G6PD isoenzyme analysis of myeloid and lymphoid cells in human multilineage colonies

Some multilineage hemopoietic colonies contain, in addition to myeloid cells, T lymphocytes. These proliferate extensively in liquid suspension culture under the influence of a T cell growth factor provided by phytohemagglutinin-T cell-conditioned medium (PHA-TCM). The clonal origin of these myeloid and lymphoid components was investigated by determining the glucose-6-phosphate dehydrogenase (G6PD) isoenzyme types of multilineage colonies grown from peripheral blood of 4 G6PD heterozygous normal volunteers. The G6PD assay is sufficiently sensitive to detect enzyme concentrations contributed by as few as 30 granulocytes and erythroblasts, 4-6 megakaryocytes, 2-3 macrophages, and 50-100 T cells. T cell components can be detected even if myeloid cells are present in 10-20-fold excess. A small number of multilineage colonies with T cells produced a single G6PD isoenzyme on direct analysis and after expansion in liquid culture. This observation supports the view of a common progenitor for myeloid and lymphoid cells in the peripheral blood of normal adults.     

Identification of phenotypic markers of B cells from patients with Chagas disease

Chagas disease was discovered more than a hundred years ago, but its pathogenesis is still not completely understood. Autoimmunity is one of the mechanisms shown to contribute to its pathogenesis, which may indicate an important participation of B lymphocytes. Patients with Chagas disease have shown increased percentage of B cells producing IL‐10. However, there are no reports of the phenotypic markers of B cells producing IL‐10 in patients with Chagas disease. For the first time in the literature, we evaluated the phenotypic profile of distinct markers of B cells from peripheral blood of noninfected individuals and patients with Chagas disease. Our results showed that patients with Chagas disease had a higher expression of CD21 and CD24 on the surface of CD19⁺ B cells, while CD43 and CD23 were expressed equally in all groups. Moreover, the expression of MHC‐II (HLA‐DR), CD80, CD86, caspase‐3, granzyme B and intracellular IL‐10 and TGF‐β by CD19⁺ B cells was higher in patients with Chagas disease. The results of IL‐10 production within CD19⁺CD5⁺CD1d⁺ B cells showed a higher percentage of this cytokine in patients with Chagas disease. Thus, our data bring a new knowledge about distinct markers of B cells in immune responses of Chagas disease.     

Comparative gene expression in hematopoietic progenitor cells derived from embryonic stem cells

OBJECTIVE: The aim of this study was to characterize at the molecular level the hematopoietic progenitor cells derived from rhesus monkey embryonic stem (ES) cell differentiation. MATERIALS AND METHODS: We purified CD34(+) and CD34(+)CD38(-) cells from rhesus monkey ES cell cultures and examined the expression of a variety of genes associated with hematopoietic development, by semiquantitative polymerase chain reaction analysis. For comparison, we examined cell preparations from fresh or cultured rhesus monkey bone marrow (BM) and from mouse ES cells and BM. RESULTS: We observed a high degree of similarity in the expression patterns of these genes, with only a few exceptions. Most notably, the message of the flt3 gene was undetectable in rhesus monkey ES cell-derived CD34(+) and CD34(+)CD38(-) cells, whereas substantial flt3 expression was observed in the corresponding cells from fresh BM and in CD34(+) cells from cultured BM. The integrin alphaL and interleukin-6 (IL-6) receptor genes also were expressed in CD34(+)CD38(-) cells from BM, but there was little or no expression of these genes in CD34(+)CD38(-) cells derived from ES cells. Parallel analyses, using CD34(+)Lin(-) cells derived from murine ES cell cultures, showed no apparent expression of flt3, integrin alphaL, or IL-6 receptor, whereas corresponding cell preparations isolated from mouse BM expressed high levels of all of these genes. CONCLUSIONS: ES cell-derived hematopoietic progenitors, both from the rhesus monkey and from the mouse, exhibited the same alterations in gene expression compared with BM-derived cells from these animals. These observations could reflect the presence of different subpopulations in the cell fractions that were compared, or they may represent altered biologic properties of ES cell-derived hematopoietic stem cells.     

Cytotoxic T-cell clones derived from pluripotent stem cells (CFU-GEMM) of patients with Hodgkin's lymphoma

Pluripotent stem cells (CFU-GEMM) give rise to multilineage hemopoietic colonies in culture. The cellular composition revealed that mixed colonies contain cells of different myeloid lineages and mononuclear cells with T-cell surface antigens. T lymphocytes of primary colonies and replated secondary clones from 5 patients with Hodgkin's lymphoma (stage I--II) were identified by their reaction with the monoclonal antibody OKT-8. Replated secondary clones do act functionally as cytotoxic cells using K562 as target cells. Evidence for a common progenitor of myeloid and lymphoid cells is provided by analysis of individual secondary colonies with the use of OKT-3, OKT-4, OKT-8, VIM- D5, and IgM + D antibodies for each individual clone. Primary mixed and replated secondary colonies revealed OKT-8-positive cells. No reaction with OKT-3, OKT-4, VIM-D 5, or IgM + D was observed. In mixed colonies grown from putative bone marrow transplant donors, only OKT-3-positive cells could be observed. Secondary replated colonies did not stain for OKT-8 and failed to lyse 51Cr-labeled K562 cells.     

Impaired in-vitro growth of megakaryocytic colonies derived from CD34 cells of HIV-1-infected patients with active viral replication

OBJECTIVE: To address the mechanisms of the thrombocytopoietic dysfunction that may follow HIV infection and to compare peripheral blood and bone marrow as sources of CD34 progenitor cells in HIV-infected patients. METHODS: The study used CD34 progenitor cells from 20 previously untreated HIV-infected individuals, 20 HIV-infected individuals treated with antiretroviral therapy and a control group of 20 HIV-uninfected healthy individuals to examine in-vitro megakaryocytopoiesis. There were no hematological abnormalities at baseline in the study groups. CD34 progenitor cells derived from peripheral blood and bone marrow were purified and cultured in medium containing thrombopoietin, interleukin-3, and interleukin-6. HIV-1 plasma viral load was determined by b-DNA technique. Expression of receptors for thrombopoietin, interleukin-3, and interleukin-6 was assessed on CD34 cells by flow cytometry, and numbers of receptors per single cell were calculated by Quanticalc software. RESULTS: Growth of megakaryocytopoietic colony-forming units (CFU-MK) were impaired in untreated HIV-infected individuals despite normal platelet counts. Viral load levels inversely correlate with CFU-MK growth and platelet counts. Antiretroviral drug-treated individuals showed normal megakaryocyte development. Similar results were obtained whether the CD34 progenitor cells derived from peripheral blood or bone marrow. CONCLUSIONS: These findings suggest that megakaryocyte differentiation is impaired before the onset of overt thrombocytopenia in HIV-infected patients and provide evidence for a direct link between viral replication and perturbed megakaryocytopoiesis, which appears to be prevented and/or restored by antiretroviral therapy. The results indicate that peripheral blood represents a suitable source of CD34 hematopoietic progenitors for studies of megakaryocytopoiesis in HIV disease.     

Disparate differentiation in mouse hemopoietic colonies derived from paired progenitors.

We analyzed the differentiation of murine hemopoietic colonies derived from paired progenitors in culture. Single progenitors were isolated by use of a micromanipulation technique from blast cell colonies cultured from the spleens of 5-fluorouracil-treated mice. Eighteen to 24 hr later, the paired progenitors were separated with a micromanipulator and cultured in methylcellulose medium containing erythropoietin and pokeweed-mitogen spleen cell conditioned medium. Six to nine days later, the two colonies derived from the paired progenitors were individually picked and differential counts were performed by using May-Grunwald-Giemsa stain. The abbreviations used here are n, neutrophil; m, macrophage; e, eosinophil; mast, mast cell; M, megakaryocyte; E, erythrocyte. Of a total of 387 pairs that could be evaluated, 68 were pairs of colonies consisting of dissimilar combinations of cell lineages such as m-nmmastEM, M-nmmastEM, nm-nmmastEM, nmmastM-nmmastEM, M-nmmastM, nmmast-nmmastM, nm-nmmastE, M-nmM, n-nmM, mM-nmM, m-nmmast, nm-nme, me-nm, mM-nm, n-ne, m-mmast, m-mM, M-nm, M-mM, E-nm, m-nm, M-m, etc. Thirty-nine were homologous pairs revealing identical lineage combinations such as nmmastEM, nmmastM, nmmast, mmastEM, nmEM, nme, nmM, mM, and nm lineages. However, in members of some of these pairs, the proportions of the individual cell lineages were significantly different. The remainder were pairs of single lineage colonies. Paired progenitors obtained from the stem cell colonies of normal mice also revealed homologous and nonhomologous expression of the cell lineages. Comparison of lineage expression in colonies derived from single progenitors with the sum of lineages expressed in pairs of colonies derived from single progenitors indicated that the diversity was not due to injury inflicted by micromanipulation. These observations provide experimental data in support of stochastic mechanisms of stem cell differentiation.     

Growth of human B cell colonies from peripheral blood of patients with systemic lupus erythematosus.

Human B cell colonies were grown from peripheral blood of 12 patients with systemic lupus erythematosus (SLE) and from 12 healthy control subjects. The SLE group showed a large increase (p less than 0.001) in the number of colony forming cells (CFC) present in peripheral blood as compared with controls. The CFC were of the pre-B cell type. There was also a loss of OKT8+ cell inhibition of B cell colony growth in the SLE group compared with control subjects.     

Stimulatory activities for human multilineage hemopoietic progenitors (CFU-GEMMT) derived from patients with hemochromatosis and from normal volunteers

A medium conditioned by leukocytes in the presence of phytohemagglutinin (PHA-LCM) promotes the growth of human multilineage hemopoietic progenitors (CFU-GEMMT) which form mixed hemopoietic colonies in culture containing granulocytes, erythroblasts, megakaryocytes, macrophages, and T-lymphocytes. PHA-LCM derived from six HLA-typed patients with idiopathic hemochromatosis and from six normal individuals were tested for growth-promoting activities for multilineage hemopoietic colony formation. Four out of six conditioned media obtained from patients with hemochromatosis supported mixed hemopoietic colony formation, as did four of six conditioned media from normal HLA-typed volunteers. Active PHA-LCM preparations from patients with hemochromatosis were similar with respect to the number and size of mixed colonies and their cellular composition when compared with conditioned media obtained from volunteers. The study indicates that no link exists between the HLA phenotype of a particular donor and the predictability of obtaining an active PHA-LCM promoting multilineage hemopoietic colony formation. PHA-LCM derived from patients with hemochromatosis had no advantage with respect to stimulatory activity for mixed colony formation when compared with conditioned media obtained from healthy volunteers.     

Identification of patients with indolent B cell lymphoma sensitive to rituximab monotherapy

The potential predictive value of tumor bulk, genetic, and immunological variants in patients with low-grade non-Hodgkin's lymphoma to respond to treatment with rituximab (RTX) monotherapy was evaluated. Thus, the value of assessing the effect of 18-fluoro-desoxy-d-glucose (FDG) uptake on PET scan, polymorphisms in Fc gamma receptor (FcγR) IIIa-158, FcγRIIa-131, and C1qA-276 genes in predicting the response to treatment were evaluated in 50 low-grade non-Hodgkin's lymphoma patients. The influence of RTX pharmacokinetics, plasma levels of the B cell-activating factor (BAFF), and human antichimeric antibodies was also investigated. The therapeutic response was evaluated 10 weeks after treatment using revised Cheson's criteria. Lower maximal standardized uptake values (SUV_max) at baseline were predictive of complete response. FcγRIIIa-158 polymorphism was also associated with complete response to RTX confirming previous findings, whereas polymorphisms in the FcγRIIa-131 and C1qA-276 genes were not. Lower blood levels of RTX were observed in males, but the effectiveness of RTX in males and females was the same. BAFF was not detectable in plasma before or after treatment, and no patients developed human antichimeric antibodies. Low-grade non-Hodgkin's lymphoma patients with a low SUV_max at baseline and an FcγRIIIa-158 V/V genotype generally had a complete response to RTX.