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At least 73 records · Page 4Linked to original sources
PubMed1985

T cell colony-forming frequency of mononucleated cells extracted from rejected human kidney transplants. Functional and phenotypic studies of the colonies.

One line of investigation of cellular events leading to rejection of an allograft has been to collect the cells infiltrating the rejected allograft and to subject them to in vitro functional and cell marker analysis. Outlined in this article is a description of the limiting dilution analysis technique applied to mechanically disrupted cells obtained from three different rejected human kidney allografts and a phenotypic cell surface marker, as well as a functional study of the progeny of such cells at a clonal level. Of the harvested cells, 65% were T11+, 58% were OKT8+, and 14% were OKT4+. The frequencies of colony forming cells (CFC) were assessed in liquid medium supplemented with lectin-free purified IL-2 (selecting in vivo activated cells) or with IL-2 plus PHA. The CFC frequencies ranged from 1/777 to 1/120 cells plated and from 1/250 to 1/90 cells plated in, respectively, IL-2 and IL-2 plus PHA. Only colonies with a probability of monoclonality more than 80% were further expanded in the presence of lectin-free IL-2. Among 31 colonies grown in the presence of IL-2 alone, all colony-cells were OKT11+, 4/31 were T4+T8-, 24/31 T4-T8+--and, finally, 3/31 were T4+T8+. On the other hand, 122 colonies grown in the presence of IL-2 plus PHA were also all OKT11+, but 47/122 were T4+T8-, and 62/122 were T4-T8+. In addition, expression of DR molecules was highly variable from colony to colony. Significant antidonor cytotoxicity was recorded in 24 colonies, most of them expressing T8 molecules at their surface. Moreover cytotoxic antidonor colonies seemed to recognize an antigen determinant different from the known HLA incompatibilities between donor and recipient. In three long-term-cultured colonies, we noticed a shift in surface marker: from the expression of T8 to either the coexpression of T4 or the loss of the T8 to the sole expression of the T4 molecules. This methodology is a step forward in the elaboration of techniques for determining the relationships between the surface marker identity and the immune function of cells activated in vivo, which are found in a rejected human kidney.

Adult↗
PubMed1998

COVASIAM: an image analysis method that allows detection of confluent microbial colonies and colonies of various sizes for automated counting.

In this work we introduce the confluent and various sizes image analysis method (COVASIAM), an automated colony count technique that uses digital imaging technology for detection and separation of confluent microbial colonies and colonies of various sizes growing on petri dishes. The proposed method takes advantage of the optical properties of the surfaces of most microbial colonies. Colonies in the petri dish are epi-illuminated in order to direct the reflection of concentrated light coming from a halogen lamp towards an image-sensing device. In conjunction, a multilevel threshold algorithm is proposed for colony separation and counting. These procedures improved the quantification of colonies showing confluence or differences in size. We tested COVASIAM with a sample set of microorganisms that form colonies with contrasting physical properties: Saccharomyces cerevisiae, Aspergillus nidulans, Escherichia coli, Azotobacter vinelandii, Pseudomonas aeruginosa, and Rhizobium etli. These physical properties range from smooth to hairy, from bright to opaque, and from high to low convexities. COVASIAM estimated an average of 95.47% (sigma = 8.55%) of the manually counted colonies, while an automated method based on a single-threshold segmentation procedure estimated an average of 76% (sigma = 16.27) of the manually counted colonies. This method can be easily transposed to almost every image-processing analyzer since the procedures to compile it are generically standard.

Aspergillus nidulans↗
PubMed1982

Influence of silica and carrageenan on spleen colonies and colonies in murine peritoneal cell-coated cellulose acetate membranes.

Cellulose acetate (CA) discs placed in the peritoneum of mice become coated by a layer of peritoneal cells consisting primarily of macrophages (M). These CAM support the growth of hematopoietic colonies when syngeneic bone marrow cells are injected intraperitoneally. Most of these colonies are granulocytic and are recognizable by their peroxidase reaction. Since silica and carrageenan are known to reduce macrophage function, their effect on CAM granulocyte colony formation was tested. Carrageenan injected intraperitoneally before, concurrently, or after injection of marrow cells markedly reduced colony formation. Silica injected intraperitoneally concurrently or after injection of marrow cells reduced colony formation. Silica injected before marrow cells did not reduce colony formation. CAM produced in one mouse and exposed to carrageenan or silica in situ for 24 h before being transferred to sublethally irradiated recipients and seeded by injection of marrow cells had control levels of granulocytic colonies. Likewise, CAM produced in one mouse, removed, incubated in vitro with carrageenan or silica, carefully rinsed and transferred to sublethally irradiated recipients and seeded with marrow cells were able to support control levels of colony formation. Intravenous injection of silica or carrageenan had no consistent effect on colony formation. Spleen colonies (CFU-S) from marrow cells incubated in vitro with the agents, and given intravenously to lethally irradiated mice, were inhibited by silica, but not by carrageenan. Silica or carrageenan given intravenously to irradiated mice 3 h before or 3 h after intravenous marrow cell injection enhanced subsequent CFU-S formation.

Animals↗
PubMed1983

The nature of 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated hemopoiesis, colony stimulating factor (CSF) requirement for colony formation, and the effect of TPA on [125I]CSF-1 binding to macrophages.

The tumor-promoting phorbol diester, 12-O-tetradecanoylphorbol-13-acetate (TPA) was found to act both independently of and synergistically with the mononuclear phagocyte specific colony stimulating factor (CSF-1) to stimulate the formation of macrophage colonies in cultures of mouse bone marrow cells. In contrast, TPA did not synergize with other CSF subclasses that stimulate the formation of eosinophil, eosinophil-neutrophil, neutrophil, neutrophil-macrophage, and macrophage colonies, nor with either of the two factors required for megakaryocyte colony formation, megakaryocyte CSF, and megakaryocyte colony potentiator. In serum-free mouse bone marrow cell cultures TPA retained the ability to independently stimulate macrophage colony formation. However, TPA-stimulated colony formation was suboptimal and delayed in serum-free cultures that could support optimal colony formation in the presence of CSF-1. In addition, TPA did not directly compete with [125I]CSF-1 at 4 degrees C for its specific, high-affinity receptor on mouse peritoneal exudate macrophages. However, a 2-hour preincubation of the cells with TPA at 37 degrees caused almost complete loss of the receptor. Thus, TPA is able to mimic CSF-1 in its effects on CSF-1 responsive cells in some aspects (the spectrum of target cells, the morphology of resulting colonies, and the ability to down-regulate the CSF-1 receptor) but it is not able to mimic CSF-1 in other ways (TPA alone cannot stimulate the full CSF-1 response, TPA does not stimulate the most primitive CSF-1 responsive cells, and TPA does not bind to the CSF-1 receptor).

Animals↗
PubMed2006

Nest- and colony-mate recognition in polydomous colonies of meat ants (Iridomyrmex purpureus).

Workers of polydomous colonies of social insects must recognize not only colony-mates residing in the same nest but also those living in other nests. We investigated the impact of a decentralized colony structure on colony- and nestmate recognition in the polydomous Australian meat ant (Iridomyrmex purpureus). Field experiments showed that ants of colonies with many nests were less aggressive toward alien conspecifics than those of colonies with few nests. In addition, while meat ants were almost never aggressive toward nestmates, they were frequently aggressive when confronted with an individual from a different nest within the same colony. Our chemical analysis of the cuticular hydrocarbons of workers using a novel comprehensive two-dimensional gas chromatography technique that increases the number of quantifiable compounds revealed both colony- and nest-specific patterns. Combined, these data indicate an incomplete transfer of colony odor between the nests of polydomous meat ant colonies.

Aggression↗
PubMed1998

Productivity, individual-level and colony-level flexibility, and organization of work as consequences of colony size.

In social insects, colony-level complexity may emerge from simple individual-level behaviors and interactions. Emergent global properties such as colony size, which can be viewed as a consequence of life history traits, may influence individual-level behaviors themselves. The effects of colony size on productivity, body size, behavioral flexibility, and colony organization are examined here by considering colony size as an independent variable. Large colony size commonly corresponds with complex colony-level performance, small body size, and lower per capita productivity. Analyzing the construction behavior of various wasp societies reveals that complexity of individual behavior is inversely related to colony size. Parallel processing by specialists in large colonies provides flexible and efficient colony-level functioning. On the other hand, individual behavioral flexibility of jack-of-all trades workers ensures success of the small and early societies.

Animals↗
PubMed2005

Colony size selection determines adult survival and dispersal preferences: allee effects in a colonial bird.

Avian coloniality traditionally has been investigated by examining how breeding success varies with colony size, but other crucial fitness components rarely have been examined. This may lead to wrong conclusions because unmeasured parameters may change the final fitness balance. We used multistate capture-recapture models to investigate adult survival and dispersal in relation to colony size within a long-term monitored population of lesser kestrels (Falco naumanni). Nest predation probability decreases with colony size, and adult survival is predicted to show the same trend because adults are exposed to the same suite of predators. As expected, survival probability was higher in large colonies (0.72+/-0.015; mean+/-SE) than in medium or small colonies (0.65+/-0.02). Additionally, dispersal probabilities were higher going from small to large colonies (0.20+/-0.01) than from large to small (0.08+/-0.01), as predicted by theory of habitat selection shaped by fitness maximization. These asymmetries are likely to generate size-specific colony population dynamics, so they should be taken into account in studies of colonial birds and other metapopulation-like systems. Allee effects, that is, positive density dependence, appear to be the cause of the evolution of dispersal behavior and may explain the maintenance of coloniality in this species.

Animals↗
PubMed2005

Playback of colony sound alters the breeding schedule and clutch size in zebra finch (Taeniopygia guttata) colonies.

The hypothesis that social stimulation, derived from the presence and activities of conspecifics, can hasten and synchronize breeding in colonies of birds was tested. A modified playback/recorder system was used to continuously exaggerate the amount of colony sound available to zebra finches throughout their courtship period. Males that heard 'sound supplements' generated from their own colony sang more than males in control colonies that did not receive playback; males that heard samples from a different colony, sang at an intermediate level. Females that were exposed to the vocalizations of their mate and playback from a colony other than their own, laid eggs earlier and more synchronously than females in control colonies. Females that heard the vocalizations of their mate along with playback samples generated from their own colony, laid eggs more synchronously but not earlier than control females. Both acoustic treatments caused females to lay larger clutches. Social stimulation influences the breeding schedule and clutch size in zebra finch colonies. If there are advantages associated with these effects, social stimulation may contribute to the maintenance of colonial breeding systems.

Acoustic Stimulation↗
PubMed1987

Correspondence between the development of hemopoietic tissue and the time of colony formation by colony-forming cells.

The development of a haemopoietic tissue and the time when colony-forming cells in it formed detectable colonies were studied with in vivo spleen colony-forming units (CFUs) and in vitro high-proliferation-potential colony-forming cells (HPP CFC). Cells that form colonies first are developmentally more mature than those doing so later. Marrow containing mature spleen colony-forming cells formed fewer cells in the femora of recipients than that which contained early colony-forming cells. The growth curve of developmentally early high-proliferation potential-colony-forming cells was steeper than that of later cells. The time period before colony-formation occurs is a property of the colony-forming cell and is not due to regulatory mechanisms in the animal or to regulatory cells in the haemopoietic stroma.

Animals↗
PubMed1981

Human T lymphocyte colonies. I. Surface markers and cytotoxic potential of colony cells.

Colonies were obtained from peripheral blood lymphocytes (PBL) grown in soft agar in the presence of PHAM or PHAp mitogens. One out of 130 PBL was able to generate a colony. Colony cells were mass harvested and assayed for surface markers and cytotoxic potential. Most of the colony cells (83%) form spontaneous rosettes with sheep-red blood cells (RBC) and bear the human T lymphocyte antigens (HTLA) (92%). A significant amount of colony cells able to bind autologous RBC was detected (24%). The capacity of PBL and colony cells to bind Ox-RBC sensitized with rabbit anti-Ox-RBC IgM (EAM complexes) was measured: only 15% of colony cells compared to 49% of the PBL formed EAM rosettes. The capacity of cells to bind the Fc portion of antigen-complexed IgG was investigated by two rosette assays: using Chicken or Ox-RBC sensitized with a rabbit anti-Chicken-RBC or Ox-RBC IgG (Chicken EAG or Ox-EAG complexes). The percentage of colony cells forming Chicken EAG rosettes was low (3.6%) compared to PBL (12%). This percentage was significantly increased with PHAp, and not PHAM stimulation (11%). Using Ox-EAG complexes, we confirmed the low percentage of EAG rosettes in colony cells under PHAM stimulation (4.7%) compared to PBL (21%). A significant cytotoxic capacity (spontaneous or antibody dependent) was found in colony cells after PHAM stimulation. This method of culture is able to generate clones of T cells and conserve T cell subsets and cytotoxic potential usually found in a T purified population. In further studies, it will be interesting to investigate if each clone possesses specific markers and cytotoxic potential and is able to maintain this differentiation step in long term culture.

Antigen-Antibody Complex↗
PubMed1990

Thrombopoiesis-stimulating factor: its effects on megakaryocyte colony formation in vitro and its relation to human granulocyte-macrophage colony-stimulating factor.

The effects of thrombopoiesis-stimulating factor (TSF) on human marrow megakaryocyte colony formation in vitro were studied by the plasma clot method. TSF was found to stimulate megakaryocyte as well as granulocyte-macrophage colony formation in vitro at optimal concentrations of 200-300 pg/ml of medium containing 2.5% horse serum. This colony-stimulating effect of TSF was not affected by polyclonal antibodies to human (h) interleukin 3 (IL-3) or to granulocyte colony-stimulating factor (G-CSF) but was neutralized by monoclonal or polyclonal antibodies to human granulocyte-macrophage colony-stimulating factor (hGM-CSF). In order to differentiate among cross-reactivity between TSF and hGM-CSF, induction of colony growth via release of GM-CSF, and presence of hGM-CSF in TSF preparations, TSF was tested on murine marrow cells, which are not responsive to hGM-CSF. TSF induced growth of murine megakaryocyte colony-forming units (CFU-MK) and granulocyte-macrophage colony-forming units (CFU-GM) in vitro with a dose response similar to that observed on human marrow cells; however, this effect could not be neutralized by antibodies to either human or murine GM-CSF. Using a double-antibody enzyme-linked immunosorbent assay, TSF preparations were found to contain 36 +/- 4 U of hGM-CSF per picogram of TSF protein. These findings indicate that hGM-CSF is responsible for the megakaryocyte colony-promoting effects of TSF on human marrow cells in vitro.

Animals↗
PubMed1987

Effects of recombinant murine granulocyte colony-stimulating factor on granulocyte-macrophage and blast colony formation.

We performed the present study to define the in vitro hemopoietic activity of murine recombinant (r) granulocyte colony-stimulating factor (G-CSF) using murine hemopoietic culture systems of normal bone marrow cells, fetal liver cells, and spleen cells of 5-fluorouracil (FU)-treated mice. Recombinant G-CSF supported only neutrophil and/or macrophage colony formation by normal bone marrow cells. It did not enhance the formation of erythroid bursts in the fetal liver cell assay, but interleukin-3 (IL-3) did. Paradoxically, rG-CSF could support the colony formation of multilineage colonies as well as blast colonies from the spleen cells of 5-FU-treated mice, while r-granulocyte-macrophage colony-stimulating factor (GM-CSF) and r-erythropoietin (Ep) did not. When blast colonies, formed in the presence of G-CSF, were replated to dishes containing IL-3, they were able to differentiate along multilineage pathways. However, when they were replated to dishes containing rG-CSF, they could differentiate only into neutrophils and macrophages. Single cells transferred from blast colonies formed only neutrophil-macrophage colonies. These data indicate that rG-CSF had a direct effect on the growth and development of GM progenitors at a late stage and a significant effect on multipotential hemopoietic precursors. Although it remains to be clarified how G-CSF acts on multipotential stem cells, this unique effect is important in the understanding of its pluripotent hemopoietic activity in vivo.

Animals↗
PubMed1984

Colony formation in the absence of added growth factors by peripheral blood T-cell colony-forming cells of patients with T-cell malignancies.

Clonogenic cells from peripheral blood of 13/16 patients with T-cell malignancies generated colonies in methylcellulose in absence of added growth factors or mitogenic stimulation. Spontaneous colonies were also obtained from purified cell fractions (E-OKT3- and/or E+ cells) in 73% and 57% of the patients, respectively. No spontaneous colony growth was observed with mononuclear cells of patients with solid tumors, non-T-cell leukemias or normal subjects. Colonies consisted of acid-phosphatase-positive, myeloperoxidase-and PAS-negative lymphoblasts bearing T-cell surface markers. Although the phenotype of pooled colony cells from either unfractionated mononuclear cells or E-OKT3- -derived colonies varied from patient to patient, the colonies, like fresh leukemic cells, were mostly composed of relatively immature cells as assessed by the high proportion (greater than 40%) of OKT6+ and OKT10+ cells and the low proportion (less than 40%) of OKT3+ and/or E+ cells. Cytogenetic analysis of colony cells revealed either normal metaphases or chromosome anomalies similar to those observed in fresh leukemic cells. Moreover, cells from primary colonies exhibited a capacity for self-renewal in the absence of added growth factors.

Adolescent↗
PubMed1986

T-cell colony formation in patients with T-cell malignancies: growth factor requirements for in-vitro proliferation of peripheral blood T-cell colony-forming cells.

Peripheral blood T colony-forming cells (T-CFC) from patients with T-cell malignancies are capable of proliferation in methylcellulose, in the absence of added growth factors or mitogenic stimulation. We show here that based on the spontaneous plating efficiencies of their T-CFC, two groups of patients can be established: Group A (10 patients) with a high colony number (more than 100 colonies/10(5) seeded cells), and group B (12 patients) with less than 100 colonies/10(5) cells. The addition of interleukin 2-(IL2) containing PHA-leukocyte conditioned medium enhanced colony growth from group B but not group A patients. Moreover, both biochemically purified and recombinant IL2 induced the colony growth from group B but not group A patients without any other stimulation. In addition, a monoclonal antibody (moAb) against the IL2 receptor (IL2-R; anti-Tac) inhibited the spontaneous colony formation from T-CFC of both groups of patients. These observations strongly suggest that IL2-R are involved in the spontaneous colony growth of T-CFC. To determine whether IL2 is also involved in the spontaneous colony formation, media conditioned (LCM) by unstimulated leukemic cells were tested for IL2 activity. A constitutive release of IL2 was detected in LCM from only 2 out of 10 patients tested, and some of them were capable to inhibit thymidine incorporation by IL2-dependent cells cultured in the presence of highly purified IL2. However, most of these LCM contained a T-cell colony-promoting activity (TCPA) inducing colony formation from both normal resting and PHA-stimulated E+ clonogenic cells without added IL2 or mitogenic stimulation. TCPA-containing LCM induced the expression of functional IL2-R and IL2 release by normal resting lymphocytes. TCPA was constitutively released by blast-enriched cell fractions suggesting that it is released by the leukemic cells.

Antibodies, Monoclonal↗
PubMed1982

Acute myeloid leukemia colony growth in vitro: differences of colony-forming cells in PHA-supplemented and standard leukocyte feeder cultures.

Bone marrow or blood of patients with acute myeloid leukemia was subjected to cell separation and the cells investigated for in vitro colony growth. Discontinuous albumin density gradient centrifugation and depletion of E-rosette-forming cells resulted in purified fractions of acute myeloid leukemia cells. From these fractions, growth of large leukemic colonies was obtained in the PHA-leukocyte feeder (PHA-LF) colony technique in 12 of 14 patients. The standard double agar layer techniques with a leukocyte feeder for granulocyte-macrophage colony forming cells (GM-CFC) supported colony formation in only four cases. The PHA-LF leukemic colony-forming cells (CFC) were found to be of low buoyant density (always less than or equal to 1.062 g.ml-1) when compared to normal marrow GM-CFC (peak at 1.065 g.ml-1). The density profile of PHA-LF CFC paralleled the distribution of the nucleated cells in 8 cases, but in 4 patients, the cFC peak was found at a distinctly lower density; this suggested that a specific leukemic subpopulation had a colony-forming capacity. In three of the four patients with colony growth in the double layer agar technique, it was evident that these CFC had density properties different from those of PHA-LF CFC. These findings suggest that cells giving rise to large colonies in the PHA-LF and double layer agar assays represent distinct leukemic subpopulations.

Adult↗
PubMed1994

Stable integration of retrovirally transduced genes into human umbilical cord blood high-proliferative potential colony-forming cells (HPP-CFC) as assessed after multiple HPP-CFC colony replatings in vitro.

We previously demonstrated stable integration of a transduced thymidine kinase (TK)-neo gene into immature and replatable stem and progenitor cells, as assessed by the presence of the gene in second-generation colonies. To evaluate whether this integration was still present in third- and fourth-generation colonies, nonadherent low-density T-lymphocyte-depleted (NALT-) cells from human umbilical cord blood were prestimulated with recombinant human (rhu) erythropoietin (Epo), steel factor (SLF), interleukin-3 (IL-3), granulocyte-macrophage (GM) colony-stimulating factor (CSF), and granulocyte (G)-CSF. Prestimulated NALT- cells were incubated with retroviral-containing supernatant obtained from TK-neo vector-producing cells, washed, and assayed for colony formation in the presence of Epo, SLF, IL-3, GM-CSF, and G-CSF -/+ G418. The results confirmed that the TK-neo gene could be efficiently introduced into hematopoietic progenitor cells without stromal cells as a source of virus. As previously reported, proviral integration was detected in primary G418R-colonies, and in second-generation replated colonies derived from G418R granulocyte erythroid macrophage megakaryocyte colony-forming units and high-proliferative potential colony-forming cells (HPP-CFCs). Moreover, we now document that proviral integration was apparent in cells from colonies derived from third- and fourth-generation replated HPP-CFC, suggesting a high degree of stable integration of the transduced gene.

Cells, Cultured↗