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Osteogenic cell lineage analysis is facilitated by organ cultures of embryonic chick periosteum.

Monoclonal antibodies against the surface of embryonic osteogenic cells (SB-1, SB-2, SB-3, and SB-5) have been used to characterize the sequence of transitions involved in the osteogenic cell lineage. In the present study, immunohistochemical analyses of the expression of osteogenic cell surface antigens in organ cultures of folded chick periosteum were performed. Unlike traditional culture methods using isolated osteoblastic cells, periosteal explants form a mineralized bone tissue in 4 to 6 days which is virtually identical to the in vivo counterpart. Examination of fresh explants confirm that no mature osteoblastic cells were present, although a discontinuous layer of preosteoblasts was evident. As the wave of osteodifferentiation swept through the cultured tissue, antibody SB-1 reacted with the surface of a large family of cells associated with the developing bone. Antibodies SB-3 and SB-2 reacted with progressively smaller subsets of cells, namely those in successively closer physical association with the newly formed and mineralizing bone. Cells recently encased in bone matrix were stained by both SB-2 and SB-5 antibodies, while those cells deep within the matrix reacted only with antibody SB-5. Analysis of this culture model allows dissection of the discrete cellular transition steps of osteogenesis, and reveals that osteogenic precursor cells proceed through the unique lineage stages which have been documented for in vivo osteogenesis. This culture system has furthermore provided evidence which is used to refine our understanding of the osteogenic cell lineage.

Animals↗

In vitro development of precursor cells in the myogenic lineage.

Expression of the muscle-specific integral membrane protein H36 and the intermediate filament protein desmin, detected by immunofluorescence, was used to identify cells at distinct stages in the skeletal myogenic lineage. These proteins were coordinately expressed in cultures of rat hindlimb myoblasts from 17- and 19-day fetuses and newborn pups, and in satellite cells from juveniles. Both H36+ and desmin+ cells were present in cultures from 13.5- and 15-day embryonic hindlimbs, but desmin expression was more prevalent: H36-/desmin+ myoblasts predominate during this early stage of development. H36 was not detected in Day 12 embryo hindlimb bud cells in vivo nor in cultures soon after plating. Initially, only 1% of the Day 12 limb bud cells expressed desmin. When these cells were serially passaged every 3-4 days, cells with all three possible myogenic phenotypes developed: that is, H36+/desmin-, H36+/desmin+, and H36-/desmin+ cells. There was a progressive increase in the frequency of H36+ cells, with 75% of cells positive by passage 6 (Day 27 in vitro). The maximum frequency of cells that expressed desmin occurred in passage 5 (Day 23 in vitro). These results demonstrate that precursors to the cells that express H36 and desmin are present in the 12-day embryo hindlimb bud and that the transition from H36-/desmin- precursors to cells with a myogenic phenotype can occur in vitro. MyoD1 and myogenin were not detected in these cells, suggesting that the initial expression of H36 and desmin in the myogenic lineage may precede and/or is independent of these regulatory proteins. The conversion of precursor cells in the 12-day limb bud to a more advanced stage of development serves to define additional cells in the myogenic lineage. The ability to monitor in vitro these stages of development affords the opportunity to study how they are regulated.

Animals↗

Stomatal patterning in Tradescantia: an evaluation of the cell lineage theory.

The cell lineage theory, which explains stomatal patterning in monocot leaves as a consequence of orderly divisions, was studied in Tradescantia. Data were collected to test the theory at three levels of organization: the individual stoma; stomata distributed in one dimension, in linear fashion along cell files; and stomata apportioned in two dimensions, across the length and breadth of the leaf. In an attempt to watch the patterning process through regeneration, stomata in all visible stages of development were laser ablated. The results showed that the formation of stomatal initials was highly regular, and measurements of stomatal frequency and spacing showed that pattern was determined near the basal meristem when the stomatal initials arose. Following the origin of initials, the pattern was not readjusted by division of epidermal cells. Stomatal initials were not committed when first present and a small percentage of them arrested. The arrested cells, unlike stomata, were consistently positioned in cell files midway between a developed pair of stomata. At the one-dimensional level of pattern, stomata in longitudinal files were separated by a variable number of epidermal cells and the frequency of these separations was not random. The sequential spacing of stomata also was not random, and stomata separated by single epidermal cells were grouped into more short and long series than expected by chance. The stomatal pattern across the width of the leaf resulted from cell files free of stomata which alternated with cell files containing stomata, but not with a recurring periodicity. Files lacking stomata were found only over longitudinal vascular bundles. Laser ablations of developing stomata did not disrupt the pattern in nearby cells or result in stomatal regeneration. We conclude that the cell lineage theory explains pattern as an individual stomatal initial arises from its immediate precursor and satisfactorily accounts for the minimum spacing of stomata in a cell file, i.e., stoma-epidermal cell-stoma. However, the theory does not explain the collective stomatal pattern along the cell files, at the one-dimensional level of patterning. Nor does the theory account for the for the two-dimensional distribution of stomata in which regions devoid of stomata alternate with regions enriched with stomata, but not in a highly regular nor haphazard manner. We suggest that the grouping of epidermal cells and stomata separated by single epidermal cells in cell files may result from cell lineages at a specific position in the cell cycle as they traverse the zone where stomatal initials form.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Division↗

Production of a pokeweed antiviral protein (PAP)-containing immunotoxin, B43-PAP, directed against the CD19 human B lineage lymphoid differentiation antigen in highly purified form for human clinical trials.

We describe a standardized method for the preparation and purification of a potent immunotoxin against B-lineage leukemia/lymphoma cells, constructed with the ribosome inhibitory single chain plant toxin pokeweed antiviral protein (PAP) and a murine IgG1 monoclonal antibody (MoAb) specific for the human B lineage differentiation antigen CD19 for human clinical trials. PAP was prepared from spring leaves of Phytolacca americana plants by ammonium sulfate precipitation and purified to homogeneity by successive steps of ion exchange chromatography. B43 MoAb was produced in vitro by hollow fiber technology and purified to homogeneity by affinity chromatography. PAP toxin and B43 MoAb were modified via their free amino groups prior to their intermolecular conjugation. 2-iminothiolane was used to introduce reactive sulfhydryl groups into PAP and N-succinimidyl 3-(2-pyridyldithio) propionate was used to introduce 2-pyridyl disulfide bonds into B43 MoAb. Modified PAP was reacted with modified B43 MoAb resulting in a sulfhydryl-disulfide exchange reaction and yielding disulfide linked PAP-B43 MoAb conjugates, which we refer to as B43-PAP immunotoxin. B43-PAP immunotoxin was subjected to preparative gel filtration chromatography and cation exchange chromatography to obtain a highly purified, sterile, and pyrogen-free immunotoxin preparation with less than 5% free antibody contamination and less than 0.5% free PAP contamination. The final product displayed a high affinity for and a very potent anti-leukemic activity against B lineage leukemia cells. With slight modifications, the procedures detailed in this report should be generally applicable to preparation of other PAP-MoAb conjugates for treatment of cancer or AIDS.

Amino Acid Sequence↗

Determination of lineage and clonality in diffuse lymphomas using the polymerase chain reaction technique.

Malignant lymphomas of the diffuse mixed or diffuse large cell subtype are immunologically heterogeneous and morphologic features do not allow prediction of lineage. Applications of immunophenotypic and gene rearrangement techniques has greatly improved our ability to determine clonality and lineage. Nevertheless, some diffuse lymphomas are composed of numerous reactive cells accompanying a small clonal population, thereby making determination of clonality difficult, even with gene rearrangement techniques. In this study, we report two malignant lymphomas in which immunophenotypic and genotypic studies failed to elucidate evidence of clonality. In both cases, the polymerase chain reaction amplified segments of DNA containing the bcl-2/JH sequence, providing evidence of clonality and suggesting B-cell lineage. We conclude that the polymerase chain reaction technique may be useful in the diagnosis of some diffuse mixed and large cell lymphomas.

Adult↗

Cell lineage of the thoracic muscles of Drosophila.

The thorax of the adult Drosophila contains about 80 muscles, which develop from the mesoderm. A new genetic marker was used to map the cell lineage of the myoblasts that form these muscles. Clones of marked cells were produced by irradiation of embryos and larvae, and these were detected in the adult by histochemical staining. The principal findings are that the muscles of each segment have separate origins, and that each becomes compartmented precisely into a dorsal-lineage and a ventral-lineage set of muscles, each set probably being formed by the adepithelial cells found in one imaginal disc. In contrast with the epidermis, the muscles of each thoracic segment are not subdivided into anterior and posterior compartments, and clones of muscle cells that are homozygous for recessive-lethal alleles of engrailed develop normally.

Animals↗

The unc-86 gene product couples cell lineage and cell identity in C. elegans.

The C. elegans gene unc-86 is required in several distinct neuroblast lineages for daughter cells to become different from their mothers, and is also required for the specification of particular neural identities. Consistent with the fact that unc-86 encodes a POU domain protein, we find that the unc-86 protein is localized to the nucleus. In the affected lineages, unc-86 protein appears within a few minutes after cell division in the nuclei of those daughter cells that are transformed by unc-86 mutations. Thus, expression of unc-86 protein is dependent on cell lineage. unc-86 protein is not asymmetrically segregated at further divisions. unc-86 protein also appears shortly after cell division in the nuclei of particular identified differentiating neurons; at least some of these neurons are nonfunctional in unc-86 mutants.

Animals↗

Response to hydrocortisone of blast progenitors in acute myeloblastic leukemia: an aspect of lineage infidelity.

The blast population in acute myeloblastic leukemia (AML) contains cells capable of forming blast-cell colonies in culture. The purpose of this study was to measure the effects of hydrocortisone on this process, using two end-points. First, we measured the effects of increasing concentrations of hydrocortisone on the primary plating efficiency of T-lymphocyte-depleted blast cell preparations from AML peripheral blood. Second, colonies forming in the presence or absence of the hormone were pooled and replated; changes in the plating efficiencies (secondary plating efficiency or PE2) of these suspensions reflected the effect of the hormone on blast progenitor self-renewal. For comparison, we measured the hydrocortisone dose response curves for normal granulopoietic and T-lymphocyte colony-formation. The latter showed little individual variation; T-lymphocyte colony-formation was regularly sensitive to the hormone while granulopoietic colony-formation was resistant. In contrast, wide variations were found in the hydrocortisone dose response curve for blast from 24 patients with AML (FAB 1-6). A significant association was found between successful remission induction and resistance to hydrocortisone in 24 treated patients. The association was maintained when the data was stratified by other risk factors, including PE2 and the presence of blasts bearing immunologically-defined markers of more than one differentiation lineage (lineage infidelity). We propose that sensitivity to hydrocortisone may reflect the passage of blast cells through lymphopoiesis-associated components of differentiation programs. From this point of view, the poor prognosis associated with sensitivity of blast progenitors to hydrocortisone may be similar to the response-failure of patients whose blasts exhibit lineaged infidelity when tested with immunological procedures.

Adolescent↗

Multipotent human hematopoietic cell line K562: lineage-specific constitutive and inducible antigens.

K562 cells have been reported to display a variety of non-erythroid properties. Using 28 lineage-specific monoclonal antibodies, we analysed which antigens are present spontaneously and which are inducible by a variety of agents. The data suggest that (1) antigens of a given lineage are preferentially responsive to certain inducers, e.g. megakaryocytic antigens to phorbol ester, and (2) a given inducer may influence antigens of different lineages in opposite directions, e.g. phorbol dibutyrate, not only induces megakaryocytic antigens, but also decreases granulocyte and erythroid antigens. We conclude that the K562 cell, despite its malignant origin, retains some capacity for expression of alternative programs of differentiation, a characteristic of the normal multipotent hematopoietic stem cell.

Antigens↗

Lineage non-specific down regulation of P210bcr/abl in the CML cell line, KU-812-F, during differentiation.

CML cell line, KU-812-F, originally established from a patient with Philadelphia-chromosome-positive chronic myelocytic leukemia has maintained the ability to differentiate into both granuloid (basophilic) and erythroid lineages. The expression of P210bcr/abl in KU-812-F cells during differentiation was studied by immunoblotting and immunoprecipitation. Immunoblotting with anti-phosphotyrosine sera revealed the down-regulation of P210bcr/abl in both granuloid and erythroid lineages. Immunoprecipitation with anti-abl antibodies of 35S-methionine-labelled cells revealed a reduced rate of synthesis of P210bcr/abl protein. Cytotoxic agents that caused growth inhibition of the cells did not alter the expression of P210bcr/abl. These results indicate that the down regulation of P210bcr/abl protein is a lineage non-specific event accompanied by differentiation.

Cell Differentiation↗

Characteristics of heterologous anti lizard (Calotes versicolor) thymocyte serum which identify the functions of thymus-derived cell lineage.

In an attempt to study the functions of thymus derived cell lineage, two different heterologous anti-lizard thymocyte sera (ATS i.v. & ATS i.p) were raised by immunizing rabbits with viable thymocytes of Calotes versicolor. Cytotoxicity assay, nylon wool fractionation and thymectomy were employed to assess the effect of these ATS on lymphoid cells of the lizards. The results revealed that ATS i.v. contained minimum amount of irrelevant antibodies than ATS i.p; non-adherent splenocytes were enriched with ATS sensitive cells, whereas the adherent with SIg+; adult thymectomy decreased ATS sensitive cells in spleens and the density of thymic antigen (identified by the ATS) in splenic thymus derived cell lineage was much higher than on thymocytes themselves. The cells of thymic lineage identified by the ATS thus resemble those of higher vertebrates.

Animals↗

Biochemical analysis of preliminary clusters in the non-lineage panel.

After the preliminary clustering of the whole workshop panel using flowcytometry data, we selected those clusters that were composed of mAbs that bound a broad range of cells. To obtain evidence that mAbs in each of these preliminary clusters detected the same antigen, they were tested for their capacity to compete with each other for binding to a target cell and the molecular weights of their antigens were estimated after immunoprecipitation. Most preliminary clusters in the non-lineage panel contained control mAbs that had been characterised in one of the previous workshops, and this study therefore increased the number of mAbs available to each of these non-lineage antigens. One new interesting cluster, BoWC14, was described which defined an antigen on myeloid cells and a subpopulation of CD4, CD8 and WC1 T lymphocytes (BT3/8.12 and IL-A155). An additional cluster, which did not fit into any other panel, contained mAbs specific for an antigen restricted to the erythroid lineage and received the nomenclature BoWC15 (ANA8, IL-A135, IL-A137, IL-A138 and IL-A160).

Animals↗

Isolation of IFAPa-400 cDNAs: evidence for a transient cytostructural gene activity common to the precursor cells of the myogenic and the neurogenic cell lineages.

Differentiation of neural and muscle cells is characterized by a switch in the expression of the type of intermediate filament protein subunit. In these lineages, vimentin is transiently expressed in the initial stages of development and is gradually replaced by a tissue specific protein. We have identified a giant developmentally regulated antigen (IFAPa-400) which colocalizes with vimentin in the precursor cells of the neurogenic and myogenic lineages of the chick embryo [Chabot and Vincent (1990) Dev. Brain Res. 54, 195-204; Cossette and Vincent (1991) J. Cell Sci. 98, 251-260]. Based on the expression of this protein during neurogenesis and myogenesis, we hypothesize that IFAPa-400 and vimentin define a special intermediate filament network, common to the non-differentiated cells derived from the neuroectoderm and those of the myogenic tissues. We report here the isolation and sequence of partial cDNAs encoding more than 400 amino acids of the carboxy-terminus of this protein. RNA blot analysis and in situ hybridization indicate that IFAPa-400 represents a bona fide developmentally regulated gene product. These results further confirm that IFAPa-400 mRNA transcripts are limited to the early precursor cells of both neurogenic and myogenic lineages.

Amino Acid Sequence↗

Heterogeneity of lineage involvement by trisomy 8 in myelodysplastic syndrome. A multiparameter analysis combining conventional cytogenetics, DNA in situ hybridization, and bone marrow culture studies.

To better understand the role of trisomy 8 in myelodysplastic syndrome (MDS), we performed a multiparameter analysis combining conventional chromosome studies (CCS), fluorescence in situ hybridization (FISH), and bone marrow (BM) culture studies in two patients with MDS evolving into acute myeloid leukemia (AML). A mosaicism of a cytogenetically normal clone and a clone with trisomy 8 was detected in both patients throughout the course of the disease, a finding confirmed by FISH on BM cells. The relative size of the trisomic clone increased from 52% to 71% (p < 0.0001) and from 53% to 69% (p = 0.001) of all BM cells at the time of the leukemic switch in patients 1 and 2, respectively. Combined FISH and immunophenotyping of BM cells showed involvement of the granulomonocytic lineage in patient 1 and involvement of erythroid cells as well as of the granulomonocytic lineage in patient 2. Only disomic lymphocytes were detected in both patients. FISH on single hemopoietic colonies grown in semisolid media detected trisomic CFU-GM and disomic BFU-E in patient 1, whereas a proportion of CFU-GM and BFU-E deriving from the trisomic clone was detected in patient 2. However, the percent of trisomic colonies was lower than the percent of involved granulomonocyte precursors and involved erythroblasts, as detected by combined FISH and immunophenotyping on fresh BM samples. We have thus shown heterogeneity of lineage involvement by trisomy 8 in MDS undergoing transformation into AML. Although preferential growth of disomic clones may occur in vitro, the finding of an increased size of the trisomic clone at the time of leukemic switch suggests that these cells had proliferative advantage in vivo over cells without trisomy 8.

Aged↗

Analysing cell lineage with a recombinant retrovirus.

Analysis of neural cell lineage in vertebrates has been limited by a lack of methods for introducing stable tracers into individual cells at relatively late stages of development. Recent progress in the design of recombinant retroviral vectors provides a novel approach to this problem. When a retrovirus infects a dividing cell, its genome integrates into a chromosome of the infected cell and is inherited by that cell's progeny. For lineage tracing, viral structural genes are replaced by a bacterial beta-galactosidase gene; infected cells are therefore unable to produce new virions, but can produce galactosidase, which is detectable histochemically. By infecting cells and identifying their progeny at appropriate stages, it has been possible to obtain new data on cell lineage in retina, cerebral cortex, optic tectum, and peripheral nerve.

Animals↗

Lineage versus environment in embryonic retina: a revisionist perspective.

The idea that microenvironmental cues act alone late in development to determine a cell's phenotype has dominated recent discussion of, retinal development, and has successfully displaced the notion of any role for cell lineage in the process of cell determination. We argue that there is, in fact, evidence favoring a degree of lineage restriction during the development of the vertebrate retina. We propose that environmental factors modulate a process of progressive lineage restriction. In this model, progenitor cells are viewed as having unequal potential, and their progeny are viewed as being committed to one of the major retinal cell classes before the stage at which they become postmitotic.

Animals↗

Genetic mosaics and cell lineage analysis in plants.

The use of genetic mosaics for cell lineage analysis has revealed several important features of plant development. All multicellular organs in higher plants are polyclonal in origin. Although primordial cell lineages have fairly regular fates, the fate of any given cell within these lineages cannot be accurately predicted. Cell fate appears to be determined by the final location of a cell rather than by its history.

Chimera↗

In vitro analysis of position- and lineage-dependent selectivity in the formation of neuromuscular synapses.

The hypotheses that selective formation of nerve-muscle connections depends upon intrinsic cellular properties, endowed either by the cell's rostral-caudal position in the embryo or its lineage, were tested directly in Xenopus embryonic cell cultures. The position or the lineage of embryonic cells was traced in vitro by previous injection of fluorophore-conjugated dextran molecules into individual blastomeres. Synaptic efficacy was assayed by recording synaptic currents from neurite-contacted muscle cells in the culture, and the physical affinity of neurites for muscle cells of different positional or clonal origins was assayed by counting the frequency of association between the neurites' growth cones and the muscle cells. Both assays showed no apparent preference between nerve and muscle cells of similar rostral-caudal positions or clonal origins, suggesting that there is little position- or lineage-dependent selectivity in the initial nerve-muscle interactions.

Animals↗