Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “clonal analysis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1997

Retrospective clonal analysis of the cerebellum using genetic laacZ/lacZ mouse mosaics.

Analysis of lacZ neuronal clones in the mouse cerebellum demonstrates genealogical independence of the primary and secondary germinal epithelia (PGE and SGE) from early development. PGE precursors and their neuronal descendants are organised into two polyclonal groups of similar sizes that exhibit parasagittal patterning and generally respect the midline. The relationship between these two groups cannot be traced back in time to less than 80 independent cells, which were probably recruited following a period of non-coherent growth that distributes unrelated cells into distinct territories of the neural tube. A lateromedial clonal organisation is observed in the mature cerebellum, suggesting the existence of many small parasagittal domains of clonal restriction and/or of cell dispersion in the rostrocaudal but not in the mediolateral dimension. The organisation is orthogonal with respect to the cellular organisation in the neural tube as is the genetic organisation. Cellular and genetic patterning of the cerebellum therefore share similarities. A possible hypothesis is that distinct cell behaviours create the different clonal domains observed in this study and that the cellular and genetic organisation of the cerebellum are coordinated.

Animals↗
PubMed1997

[Clonal analysis by fluorescence in situ hybridization in a patient with de nove acute myeloid leukemia with myelodysplasia].

A 12-year-old girl presenting leukocytosis, anemia and thrombocytopenia was diagnosed as de nove acute myeloid leukemia (AML, M2) with concurrent myelodysplastic features in myeloid and erythroid cells. Her karyotype was defined as 47, XX, +8[20]. Though she was treated successfully with multi-drug chemotherapy, she relapsed after 2 years of remission. A bone marrow transplantation from HLA matched her brother was performed to induce hematological remission which persisted for one year. She again relapsed with AML with myelodysplasia, and an abnormal complex karyotype was newly detected. She eventually died without further chemotherapy. We performed FISH on the patient's stained bone marrow smears using DNA probes for chromosome 8 and Y to analyze the clonality. The results showed that the most of blasts and bone marrow cells except lymphoid cells were of trisomy 8 at onset, while in the 1st remission, trisomy 8 clone was slightly detected only in monocytes. At 1st and 2nd relapse, trisomy 8 clone was detected again in most of myeloid cells. Thus, in this case, it was considered that underlying stem cell disorder with trisomy 8 during the entire disease course contributed to leukemogenesis.

Acute Disease↗
PubMed1991

Clonal analysis of B lymphocyte responses to Plasmodium chabaudi infection of normal and immunoprotected mice.

Parasite infection causes marked perturbations in the host immune system, as shown by hypergammaglobulinemia, autoimmunity and immune depression, but there is little information on the number, specificities and performance of B cell clones activated in the course of infection. We have addressed these questions in a model of murine malaria induced by Plasmodium chabaudi, where primary infection results in very marked B cell responses that shift in Ig isotype pattern in immunoprotected animals, and where immunity can be transferred to naive recipients by injection of serum from late, but not early, infection. We have quantitated B cells responding to infection in two distinct functional compartments, namely blast cells and Ig-secreting cells, and compared normal with immune animals. We have also determined the frequencies of clonal specificities towards several autoantigens (DNA, myosin, transferrin and red cells), non-self protein or polysaccharide antigens (KLH, levan and dextran), and parasite antigens in both compartments, by measuring blast cell reactivities in limiting dilution analyses and Ig secretion in ELISASPOT assays. This experimental design allowed us to assess the specificity of the B cell responses, to compare the clonal composition of these two B cell compartments, and to evaluate putative specific response regulation at the step of terminal differentiation. Our results show that, in this particular experimental system: (i) B cell responses in primary infection are truly non-specific while immune animals show a greater ability to control the massive non-specific response; (ii) parasite specific B cells, particularly those committed to IgG production, are selectively stimulated in immune individuals; (iii) autoreactive B cells are not selectively stimulated, but increased autoantibody production may result from perturbation in the control of terminal differentiation in the respective clones; (iv) clones with specificity to some non-self antigens (e.g. KLH and dextran) are selectively engaged and regulated, which might have implications for the immunosuppression following infection.

Animals↗
PubMed1993

Clonal analysis of multiple point mutations in the N-ras gene in patients with acute myeloid leukemia.

We have screened mutations of the N-ras gene at codons 12, 13, and 61 in leukemia cells obtained from 100 patients with acute myeloid leukemia (AML), and found mutated N-ras alleles in 9 patients. We further analyzed the polyclonality of multiple N-ras gene mutations in 4 AML patients. One patient, who had the monoclonal karyotype, t(11;17), had two types of double missense mutations at codons 13 and 61 in the same allele. Each of the remaining three patients, one of whom had t(15;17) with a monoclonal rearrangement of the retinoic acid receptor alpha and PML genes, carried two missense mutations in a relatively small population of leukemia cells. We have demonstrated that multiple clonality of the N-ras gene is occasionally observed in leukemia with a monoclonal karyotype. These findings indicate that the N-ras mutations may not always be characterized simply by an accumulative process and that the activated N-ras gene alone is not sufficient to cause leukemia.

Acute Disease↗
PubMed1996

Cytogenetic clonality analysis: typical patterns in myelodysplastic syndrome and acute myeloid leukaemia.

The cell morphology and karyotype of bone marrow samples from 24 patients with myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML) were studied simultaneously with a combined technique of May-Grünwald-Giemsa (MGG) staining and fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes. This enabled us to investigate cell lineage involvement in three malignant conditions: MDS (n = 12), leukaemia-transformed MDS (LT-MDS) (n = 5) and de novo AML (n = 7). In MDS we found blasts and often significant proportions of mature granulocytic and erythroid cells to be cytogenetically abnormal. Percentages of granulocytic and erythroid cells with cytogenetic aberrations were generally less than those of blasts. These data support the involvement of a transformed pluripotent stem cell that has retained maturation abilities. In two patients with chronic myelomonocytic leukaemia (CMMoL) the clonal involvement of monocytes was predominant. Results in the five patients with LT-MDS were similar to those in MDS. In the bone marrow of five of the seven de novo AML patients the cytogenetic abnormalities were restricted to the blasts and did not include the more mature granulocytic or erythroid populations. In the other two patients with AML, both with a t(8;21) and a loss of the Y chromosome, high percentages of mature neutrophils were cytogenetically abnormal. These patterns of clonal lineage involvement in MDS, LT-MDS, t(8;21) AML and AML appear typical and may be of clinical use, for example, for distinguishing LT-MDS from de novo AML in newly presenting patients.

Acute Disease↗
PubMed1985

Clonal analysis of early mammalian development.

Various extrinsic markers have been used to label single cells in the early mouse embryo. However, they are appropriate only for short-term experiments because of their susceptibility to dilution. Studies on cell lineage and commitments have therefore depended mainly on exploiting genes as markers by combining cells from embryos that differ in genotype at particular loci. Tissue recombination and transplantation experiments using such indelible intrinsic markers have enabled the fate of different cell populations in the blastocyst to be determined with reasonable precision. The trophectoderm and inner cell mass (i.c.m.) give rise to distinct complementary groups of tissues in the later conceptus, as do the primitive endodermal and primitive ectodermal components of the more mature i.c.m. When cloned by blastocyst injection, single i.c.m. cells colonize only those parts of host conceptuses that are derived from their tissue of origin. Thus, while clonal descendants of early i.c.m. cells can contribute to all tissues other than those of trophectodermal origin, primitive endodermal and primitive ectodermal clones are restricted, respectively, to the extraembryonic endoderm versus all i.c.m. derivatives except the extraembryonic endoderm. Interestingly, individual primitive ectoderm cells can include both germ cells and somatic cells among their mitotic descendants. By using the genetically determined presence versus absence of cytoplasmic malic enzyme activity as a cell marker, the deployment of clones has been made visible in situ in whole-mount preparations of extraembryonic membranes. Very little mixing of donor and host cells was seen in either the endoderm of the visceral yolk sac or the mesodermal and ectodermal layers of the amnion. In contrast, mosaicism in the parietal endoderm was so fine grained that, in all except 1 of 15 fields from several specimens that were analysed, the arrangement of donor and host cells did not differ significantly from that expected on the basis of their random association.

Amnion↗
PubMed1991

Clonal analysis of non-typable Haemophilus influenzae by sodium dodecyl sulphate-polyacrylamide gel electrophoresis of whole cell polypeptides.

A collection of 223 strains of non-typable Haemophilus influenzae was assembled. Most strains were isolated from hospital in-patients in North East Scotland between 1984 and 1989. These isolates were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole cell polypeptides. Variability was assessed in terms of apparent molecular weight differences between the protein profiles. Isolates were grouped on the basis of Dice coefficients of similarity and assigned to clones. Of the 223 strains, 147 were unique; the remaining strains were assigned to multi-member clones of which 13 clones had two members, one clone had three members, three clones had four members, three clones had five members, two clones had six members and one clone had eight members. The longest time interval between isolation of clonally related strains virtually equalled the limits of the study. Isolates from a childrens' hospital were significantly less diverse than those from patients in adult wards.

Adult↗
PubMed1990

Age-associated changes in CD8+ and CD16+ cell reactivity: clonal analysis.

A cloning technique was used to estimate the frequency of proliferating T cell precursors, the growth capacity of clone-forming cells and the functional activity of clones established in vitro from peripheral blood lymphocytes of young and old people. The mean frequency of proliferating precursors was lower in the elderly as was the proliferative capacity of CD8+ clones. In contrast, CD4+ and CD16+ clones showed a proliferation similar to that obtained from young subjects. When the clones were examined for their functional activity, CD4+ clones from both groups failed to show any cytolytic activity, while CD8+ clones exerted cytolysis against K562 and in antibody-dependent cell-mediated cytotoxicity but this function was reduced in clones derived from old subjects. Similarly, CD16+ clones from the elderly showed a decreased activity at some effector-to-target cell ratios. We conclude that the impaired functional activity (T or NK-dependent) found in the peripheral blood of aged subjects persists after in vitro selection when these cells are analysed at clonal level.

Adult↗
PubMed1999

Clonal analysis of epidermal patterning during maize leaf development.

In plants, specialized epidermal cells are arranged in semiordered patterns. In grasses such as maize, stomata and other specialized cell types differentiate in linear patterns within the leaf epidermis. A variety of mechanisms have been proposed to direct patterns of epidermal cell differentiation. One class of models proposes that patterns of cellular differentiation depend on the lineage relationships among epidermal cells. Another class of models proposes that epidermal patterning depends on positional information rather than lineage relationships. In the dicot epidermis, cell lineage is an important factor in the patterning of stomata, but not trichomes. In this study, the role of cell lineage in the linear patterning of stomata and bulliform cells in the maize leaf epidermis is investigated. Clones of epidermal cells in juvenile leaves were marked by excision of dSpm from gl15-m and in adult leaves by excision of Ds2 from bz2-m. These clones were analyzed in relation to patterns of stomata and bulliform cells, testing specific predictions of clonal origin hypotheses for the patterning of these cell types. We found that the great majority of clones analyzed failed to satisfy these predictions. Our results clearly show that lineage does not account for the linear patterning of stomata and bulliform cells, implying that positional information must direct the differentiation patterns of these cell types in maize.

Anthocyanins↗
PubMed1988

Clonal analysis of CD4-CD8- human thymocytes expressing a T cell receptor gamma/delta chain. Direct evidence for the de novo expression of CD8 surface antigen and of cytolytic activity against tumor targets.

CD4-CD8- human thymocytes were obtained by treating total thymocyte suspensions with anti-CD4 and anti-CD8 monoclonal antibodies (mAb) and complement. The resulting cell populations contained virtually no CD4+, CD8+ or WT31+ cells and 17-65% CD3+ cells. In addition, analysis of cell reactivity with delta-TCS-1 mAb (specific for the C gamma 2-encoded, nondisulfide-linked form of TcR gamma/delta), revealed the presence of a variable proportion of delta-TCS-1+ cells (the % of delta-TCS-1+ cells were lower than the percentage of CD3+ cells). Upon culture in recombinant interleukin 2 (IL2, in the presence of irradiated mononuclear cells), CD4-CD8- thymocytes underwent extensive proliferation. In addition, a progressive increase of CD8+ cells (but not of CD4+ or WT31+ cells) could be detected. Cells also progressively acquired cytolytic activity against K-562 or fresh melanoma cells. Fresh CD4-CD8- thymocytes were cloned under limiting dilution conditions. The cloning efficiencies were relatively high (1/3 cells); in addition, virtually all the clonal progenies obtained displayed cytolytic activity and expressed the CD3+WT31-delta-TCS-1+ surface phenotype. About half of the clones analyzed were CD8+, whereas none expressed CD4 antigens. We conclude that (a) only delta-TCS-1-reactive, TcR gamma/delta+ cells can be isolated from CD4-CD8- thymocytes cultured in IL2, and (b) the expression of CD8 antigen and of cytolytic activity reflects a true in vitro phenotypic change of CD8-, noncytolytic precursors (and not the preferential growth of few contaminating cells).

Antigens, Differentiation, T-Lymphocyte↗
PubMed1985

Clonal analysis of basophil differentiation in bone marrow cultures from a Down's syndrome patient with megakaryoblastic leukemia.

We present the in vitro differentiation of marrow cells from a patient with Down's syndrome accompanied by megakaryoblastic leukemia into basophils in the presence of phytohemagglutinin-stimulated leukocyte conditioned medium, using a liquid culture and methylcellulose culture system. Identification of basophils was established by metachromatic staining with toluidine blue, transmission electron microscopy, and the presence of histamine. However, these basophils did not release histamine in response to calcium ionophore or chemotactic peptide. Samples from suspension cultures that contained 90% basophils showed chromosomal markers characteristic of leukemic cells (48, XY, +11, +21, t(1;15)) in all examined mitoses. The cellular composition of leukemic colonies grown in methylcellulose culture from single cells was studied using the micromanipulation technique. High plating efficiency and extreme predominance of basophil colonies were observed. In a total 137 cultures, 79 revealed colony growth. Of 59 colonies that were analyzed by cytologic examination, 46 were pure basophil colonies. These basophil colonies showed disperse morphology, similar to that of a normal basophil colony. The clonality of the basophil colonies and skewing of lineage expression were documented from leukemic single-cell cultures. These data showed that leukemic cells have the capacity for differentiation into some lineages that are not expressed in vivo.

Basophils↗
PubMed1999

Cytogenetic clonality analysis of megakaryocytes in myelodysplastic syndrome by dual-color fluorescence in situ hybridization and confocal laser scanning microscopy.

In the myelodysplastic syndrome (MDS), cytogenetic abnormalities are often present and can be used as markers in studies for cell lineage involvement. Little is known of the involvement of the megakaryocytic lineage due to the variable ploidy of these cells. We applied dual-color fluorescence in situ hybridization (FISH) to routinely prepared bone marrow (BM) smears of cytogenetically normal patients and seven patients with MDS and monosomy 7 or trisomy 8. Probes specific for the centromeric regions of chromosomes 7 and 8 were detected with fluorescein isothiocyanate (FITC) and Texas Red, respectively. This enabled us to assess the ratio between the numbers of chromosomes 7 and 8 in the polyploid cells. We utilized confocal laser scanning microscopy to count the FITC and Texas Red FISH signals in the different focal layers of the megakaryocytes. Fifty-six megakaryocytes in six normal BM smears were analyzed, giving a mean ratio of 1.0, a standard deviation (SD) of 0.12, and a range of 0.8-1.33. This ratio was applied to evaluation of clonal involvement of individual megakaryocytes in the patients with MDS. In two patients with monosomy 7, the majority of the megakaryocytes were monosomic. In the five patients with trisomy 8, all or a majority of the analyzed megakaryocytes were trisomic. These results add direct evidence that in MDS megakaryocytes are involved in the malignant clone. Genes Chromosomes Cancer 25:332-338, 1999.

Adult↗
PubMed1981

Clonal analysis of the late stages of erythroleukemia induced by two distinct strains of Friend leukemia virus.

We observed striking differences between the tumorigenic colony-forming cells present in the spleens of mice late after infection with the anemia-inducing strain of Friend leukemia virus (strain FV-A) and those present after infection with the polycythemia-inducing strain (strain FV-P). Cells within primary colonies derived from FV-A- and FV-P-transformed cells (CFU-FV-A and CFU-FV-P, respectively) contained hemoglobin and spectrin, indicating that the CFU-FV-A and CFU-FV-P were transformed erythroid progenitor cells. The proportion of cells containing hemoglobin was relatively high (> 25%) in newly isolated cell lines derived from CFU-FV-P colonies, whereas cell lines derived from CFU-FV-A colonies had only low levels (0 to 2%) of hemoglobin-containing cells. A high proportion of the cell lines derived from CFU-FV-A colonies responded to pure erythropoietin and accumulated spectrin and hemoglobin, whereas the cell lines derived from CFU-FV-P colonies did not. A cytogenetic analysis indicated that primary CFU-FV-P colony cells were diploid, whereas chromosomal aberrations were observed in the immediate progeny of CFU-FV-A. The presence of unique chromosomal markers in the majority of the cells within individual colonies derived from CFU-FV-A suggested that these colonies originated from single cells. Finally, leukemic progenitor cells transformed by strain FV-A appeared to have an extensive capacity to self-renew (i.e., form secondary colonies in methylcellulose), whereas a significant proportion of the corresponding cells transformed by strain FV-P did not. In addition, the self-renewal capacity of both CFU-FV-A and CFU-FV-P increased as the disease progressed. From these observations, we propose a model for the multistage nature of Friend disease; this model involves clonal evolution and expansion from a differentiating population with limited proliferative capacity to a population with a high capacity for self-renewal and proliferation.

Animals↗
PubMed1983

Immunoregulatory human T lymphocytes triggered as a consequence of viral infection: clonal analysis of helper, suppressor inducer and suppressor effector cell populations.

The regulatory functions of a series of human T cell clones specific for an autologous Epstein-Barr virus transformed B lymphoblastoid cell line were examined. Two T4+ T cell clones, termed AT4II and AT4IV, and one T8+ clone, AT8III, were maintained in culture for greater than or equal to 9 months and were characterized in detail. Both T4+ clones provided helper function for autologous B cell immunoglobulin production when added to unstimulated peripheral blood mononuclear cells. In addition, these same clones produced soluble inducer factors after specific antigenic stimulation. However, when AT4II, AT4IV and their subclones were tested on pokeweed mitogen stimulated peripheral blood mononuclear cells, it was found that AT4IV provided help for immunoglobulin production whereas AT4II cells were strongly suppressive. This suppression by AT4II was indirect and required the presence of fresh, autologous, unirradiated T8+ cells. In contrast, the T8+ AT8III clone markedly inhibited Ig production by autologous B cells in the absence of any additional T8+ cells from peripheral blood and produced a soluble suppressor factor upon specific antigenic triggering. Thus, after stimulation with autologous Epstein-Barr virus transformed cells, at least three discrete regulatory human T cell populations can be defined at the clonal level: helper, inducer of suppression and suppressor effector clones.

Antibody-Producing Cells↗
PubMed1989

Clonal analysis of the glycosylation of immunoglobulin G secreted by murine hybridomas.

A panel of 10 hybridomas was assembled to assess the influence of various genetic and biological factors upon glycosylation of secreted monoclonal IgG. After exhaustive Pronase digestion of IgG, glycopeptides were characterized chromatographically by apparent size, charge, and concanavalin A (Con A)-Sepharose and Lens culinaris (LcH)-agarose affinity. Six glycosylation phenotypes were found to be common among all clones studied. Despite this phenotypic heterogeneity in glycosylation of IgG, considerable similarity exists between different clones. In particular, virtually all IgG glycopeptides bear a core fucose residue. Second, the majority of the glycosylation repertoire is comprised of two phenotypes, characterized by glycopeptides which differ in affinity for Con A-Sepharose. Of these, the predominantly expressed phenotype is the same for all clones. The carbohydrate structure derived from this phenotype, elucidated by 500-MHz 1H NMR spectroscopy, is (Formula: see text). Significant variability between different hybridomas exists in the relative expression of the two major phenotypes. Other differences between clones may reflect the expression of an additional site which is glycosylated differently. However, there is no apparent correlation of phenotype with either the hybridoma's parentage or the serologically defined polypeptide structure of the IgG which it secretes. In addition to clonal variability, other sources of variability in phenotypic expression were identified. A generational variability is apparent upon continuous culturing of the same hybridoma. Also, differences in culture medium pH or proliferative state of the cells may have a modest influence upon the glycosylation phenotype.

Animals↗
PubMed2003

Clonal analysis of a human antimouse antibody (HAMA) response.

Circulating human antimouse antibodies (HAMAs) directed to mouse immunoglobulin G (IgG) are clinically significant, compromising mouse antibody therapy and imaging, and interfering in immunological assays. To investigate the HAMA response, 20 stable cell lines secreting human monoclonal antibodies reactive with mouse IgG were established from a donor with a history of exposure to mice. Their subclass and domain specificities were established by solid-phase binding, indirect haemagglutination assays and immunoblotting, using Igs of known subclass and Ig fragments. The heavy-chain variable region gene usage was determined for 12 HAMAs. Eight HAMAs were IgM, 11 HAMAs were IgG4 and one HAMA was IgG1, indicating an IgG4-dominated response. All of the IgG HAMAs reacted with epitopes present on the Fc portion; one was subclass-specific, nine were subclass-restricted and two were pan-IgG-reactive. Measurement of their affinities gave dissociation constants typically in the nanomolar range. Seven and five HAMAs were derived from variable heavy-chain 3 (VH3) and VH1 gene segments, respectively. The IgG HAMAs used different VH segments to the IgM HAMAs. JH regions were coded by JH4 in eight HAMAs. DH segment usage appeared to be restricted in the IgM HAMAs. Two IgG HAMAs were clonally related. These monoclonal HAMAs are potentially useful as reagents for detecting mouse IgG and as reference reagents for the investigation of the HAMA response in patients undergoing mouse monoclonal antibody therapy and for the investigation of the influence of HAMAs on immunodiagnostic tests.

Amino Acid Sequence↗
PubMed1996

[Clonality analysis of B-cell lymphoproliferative disorders by means of immunoglobulin heavy chain polymerase reaction].

The majority of B-cell non-Hodgkin's lymphomas (NHL) exhibit a highly specific immunoglobulin heavy chain (IgH) gene rearrangement as a result of sequential assembly of their Ig variable (VH), diversity (D) and joining (JH) region segments. The analyses of Ig gene rearrangements in B cells may help to differentiate reactive lymphoproliferations from NHLs, and to identify of their B-cell origin. The aim of this study was to reveal the usefulness of polymerase chain reaction analysis of the Ig gene rearrangement in the diagnosis of B-cell NHLs, using native and formol-paraffin embedded samples. The authors analysed 67 biopsy samples of immunohistochemically characterized lymph nodes diagnosed at the Department of Pathology. University Medical School of Pécs, between 1993 and 1995, using IgH gene polymerase chain reaction. The 67 samples included 10 reactive lymphoproliferations, 47 B-cell, 5 T-cell NHLs and 5 Hodgkin's diseases. In 54 cases, fresh, unfixed, in 13 cases, formalin-fixed samples have been used. The polymerase chain reaction amplification of the Ig heavy chain third complementary determining region (CDR 3) was performed by IgVH specific sense and JH specific antisense primer pairs. The polymerase chain reaction products were evaluated by agarose gel electrophoresis containing ethidium bromide. Sixty-four % of fresh, unfixed and 54% of formol-paraffin fixed B-cell NHLs samples showed clonal Ig gene rearrangement. The applied polymerase chain reaction technique did not show clonal amplification in reactive lymphoproliferations, T-cell NHLs or Hodgkin's disease. The polymerase chain reaction amplification of the IgH gene can be a powerful tool in the diagnosis of monoclonal B-cell lymphoproliferative disorders.

Cloning, Molecular↗
PubMed1997

Clonal analysis of the in vivo differentiation potential of keratinocytes.

PURPOSE: This study investigated the in vivo differentiation of conjunctival keratinocytes. METHODS: Keratinocytes from the fornical region of the conjunctival epithelium were isolated and plated at low density (5 x 102 per 100-mm dish) in Dulbecco's minimum essential medium containing 20% fetal bovine serum in the presence of mitomycin C-treated 3T3 feeder cells. At this density, only single, isolated cells were attached after overnight culture. Eight days later, small, well-isolated colonies separated from one another by the feeder cells were detached as a sheet from the dish and were injected subcutaneously into the flanks of BALB/c athymic mice through an 18-gauge needle. Within a day, a small firm nodule appeared at the site of injection. At different time points, the animals were killed, and the nodules were excised for morphologic, histogeometric, and cell kinetic analyses. RESULTS: Each implanted colony derived from a single cell gave rise to a single epithelial cyst lined with a reconstituted stratified epithelium. Goblet-like cells loaded with periodic acid-Schiff-positive cytoplasmic granules began to appear singularly in some of the cysts by day 8 postimplantation and were observed in approximately 85% of the cysts by day 14. CONCLUSIONS: Because the cysts formed were derived from clonal populations of epithelial cells and the majority of cysts had a mixed keratinocyte-goblet cell phenotype, these results suggest strongly the existence of a bipotent precursor cell in conjunctival epithelium that can give rise to both goblet and nongoblet cells. This system can be used to study factors that can influence the commitment of pluripotent epithelial stem cells to divergent pathways of differentiation.

Animals↗