Peritoneal exudate cells. II. Kinetics of appearance of colony-forming cells

Clonal proliferation of peritoneal exudate cells from New Zealand black mice: age-related changes

Proliferation and differentiation of peritoneal exudate colony-forming cells (PE-CFC) were examined in BALB/c, C57BL/6, and NZB mice; NZB mice provided an experimental animal model for studies of autoimmunity. At 1 and 12 months of age, the number of PE-CFC from NZB mice was significantly less than the number of PE-CFC for other tested strains, whereas the number of clusters formed was reduced only in the older NZB mice. In contrast, 1- to 12-month-old BALB/c and C57BL/6 mice showed no significant age or strain-dependent alterations in PE-CFC. Although the latency period preceding colony growth remained constant for all strains and ages, significant variation in colony size was observed for NZB mice; the largest colonies were noted in the oldest group. We also observed age-associated variations in colony morphology; therefore, age- and strain-dependent differences may exist in the differentiation or functional attributes of PE-CFC subpopulations. The results specifically indicate that NZB mice have age-related alterations in PEC proliferative and differentiation capacities.

Conversion of monocytes to cells capable of anchorage-independent growth in vitro

We investigated the time-course involved in the conversion of mouse blood monocytes in vitro in cells capable of anchorage-independent growth. Two criteria were used to define when monocytes were fully converted to cells similar to mononuclear phagocytes present in inflammatory exudate, such as thioglycollate medium (TM)-elicited peritoneal exudate. They were the production of high levels of plasminogen activators and an ability to undergo anchorage-independent growth. Resident peritoneal macrophages were used as controls and for comparison. Our studies indicated that monocytes, but not resident peritoneal macrophages, could be converted to cells similar to TM-elicited mononuclear phagocytes after 2 d in culture.

Peritoneal exudate mononuclear phagocyte colony-forming cells: their proliferative state in vivo and sensitivity to cytotoxic agents

We investigated the proliferative state of peritoneal exudate macrophage colony-forming cells (PE-CFC) by exposing them to [3H]thymidine with a high specific activity in vitro and by administering cytosine arabinoside and methotrexate in vivo. Since [3H]TdR had no appreciable killing effect on PE-CFC and since the drug treatment caused no reduction in the appearance of PE-CFC, we concluded that the majority of PE-CFC, if not all, are not in active cell cycle. The production of PE-CFC was, however, suppressed by the administration of nitrogen mustard, cyclophosphamide, BCNU and vinlastine.

Peritoneal exudate cells. V. Influence of age, sex, strain and species on the induction and the growth of macrophage colony forming cells

We investigated the effects of age, sex and strain in the induction of peritoneal exudate colony-forming cells (PE-CFC) in mice. Sex and age (ranging from 3 weeks to 12 months) had no significant effect on the induction of PE-CFC. However, we found significant difference between strains in terms of the number of nucleated cells and the proportion of PE-CFC in exudate cells. When we investigated the mechanisms behind this strain difference, we found that it was due to neither the type of colony-stimulating factor employed in culture, nor the type of stimulants used to induce the exudate, nor the difference in the kinetics of appearance of PE-CFC in the peritoneal cavity. We also studied the induction of PE-CFC in rats and hamsters and the growth of these cells in vitro. Unlike mouse cells, PE-CFC from rats and hamsters could also use media conditioned by cells from other species as a source of colony-stimulating factor.

Hemopoietic repopulating potential of subcutaneous exudate cells

Inflammatory exudate (SE) cells were collected from subcutaneous coverslips in mice and transferred into lethally irradiated (1,000 r) recipients. Eight days after transplantation 59Fe incorporation in the spleen and bone marrow was significantly greater than in controls treated with the suspending medium only. One hundred percent of mitoses were of the T6T6 karyotype in the marrow and spleen when SE cells were obtained from CBA/T6T6 donors. The repopulating potential of SE cells, however, lagged significantly behind that of bone marrow cells and the failure to observe consistently macroscopic spleen colonies calls into question whether the observed regeneration was due to pluripotent stem cells. Radioautographic studies with 3H-TdR showed that the majority of SE cells had recently been generated, but long-lived, noncycling cells of lymphoid and monocytoid morphology were also present in the exudate.

Peritoneal exudate cells. IV. Characterization of colony forming cells

The adherence, phagocytic activity and buoyant density of mouse peritoneal exudate colony forming units (CFU-PE) were investigated. There was a significant enrichment in the proportion of CFU-PE in the adherent cells population, defined as cells adhering to a plastic surface within 30 minutes of incubation. The phagocytic activity of CFU-PE was studied by incubating exudate cells with iron particles for 45 minutes. The cells were then separated into phagocytic and non-phagocytic cell fractions by passing the incubation mixture through a magnetic field. A significant enrichment of CFU-PE was seen in the phagocytic cell fraction. When exudate cells were fractionated in a Ficoll discontinuous density gradient, more than 88% of CFU-PE were recovered at the 16/18% and 18/20% interfaces. It is concluded that CFU-PE are adherent cells, have strong phagocytic activity and have a buouant density between 1.0562 and 1.0703. When bone marrow cells were studied by these techniques, the committed stem cells for both granulocytes and marcophages (CFU-C) were enriched in both non-adherent cell and non-phagocytic cells populations. In the Ficoll density gradient, CFU-C banded at a heavier density region than CFU-PE.

Effects of amphotericin B on macrophages and their precursor cells

The effect of amphotericin B (AmB) treatment on the mononuclear phagocyte system of mice was investigated. Peritoneal macrophages from mice that received AmB treatment showed a higher phagocytic and antibacterial activity than those from normal untreated mice. When the levels of macrophage precursor cells in bone marrow and spleen were followed in mice after AmB treatment, an eightfold increase in the splenic content of limited stem cells for both macrophages and granulocytes (colony-forming units in culture) and a threefold increase in the number of pluripotent hemopoietic stem cells (colony-forming units in spleen) were observed on day 4. These were also accompanied by a slight increase in the colony-forming units in spleen and in culture in femoral marrows. AmB was capable of inducing a large number of peritoneal colony-forming cells in the peritoneum, and caused a significant rise in the serum level of colony-stimulating factor. No significant change in the level of blood monocytes was noted, although a transient increase in the proportion of neutrophils was observed within 24 h after AmB treatment.

Clonal growth of hamster free alveolar cells in soft agar

Free alveolar cells obtained from healthy unstimulated hamsters were tested for their ability to form colonies in soft agar. Every bronchial washing so far tested contained colon-forming cells. The average plating efficiency was 8.1% (2.4-18.3%). Alveolar colony-forming cells were characterized by having a long initial lag period (4-8 days) and only mononuclear phagocytes were found in the colony. Medium conditioned by baby hamster kidney cells or other cells was required for the initiation and maintenance of their growth. Alveolar cells from normal mice and rats also formed colonies under appropriate culture conditions.

Proliferation and colony-forming ability of peritoneal exudate cells in liquid culture

Peritoneal exudate cells, obtained from mice injected with thioglycollate medium and cultured in medium containing L-cell-conditioned medium, will proliferate in an exponential fashion for 18 days with a doubling time of 68 h. After a 2 h pulse of tritiated thymidine, labeled adherent cells increased to a maximum of 22-34% during the 1st and 2nd wk of culture. Increasing the cell concentration from 2 times 10-3 to 2 times 10-5 cells/culture reduced exponential growth to 10 days and the doubling time was increased to 81.6 h. Under these culture conditions, peritoneal exudate cells were shown to form colonies on the surface of culture dishes when plated at low density. The cells within the colony were shown to be macrophages using yeast and antibody-coated sheep erythrocytes as a test for phagocytic function. The plating efficiolonies arose from a single precursor cell. The adherent cell population contains the colony-forming precursors. These precursors can be stimulated to form colonies for at least 2 wk by the addition of conditioned medium to cultures at various times after plating. While very few colony-forming cells could be demonstrated in the unstimulated peritoneal lavage, their numbers begin to increase in the exudate 4 h after injection of thioglycollate medium and reach a maximum by day 3 and then decrease. Isolated colonies may be useful in studying the function of macrophages.