Search PubMed⌕ Search

Biomedical subjects

W Den Otter

Publications and source records attributed to W Den Otter.

At least 145 records · Page 8Linked to original sources
PubMed1982

Staging, growth properties and metastatic behaviour of a transplantable murine T-cell lymphoma.

Cell surface markers, enzymatic patterns, proliferation characteristics and metastatic behaviour of the DSA/2 derived SL2 lymphoma were determined. SL2 cells are sensitive to a heterologous antiserum to murine T-cells and to allo-antisera for Thy 1.2 and TL 1.2.3. They show acid-phosphatase, betaglucuronidase, acid-alpha-naphthytesterase and non-specific esterase staining. The reactions for ATP-ase, and 5'nucleotidase were negative. The SL2 tumour cells can be transplanted in vivo, growing rapidly both as an ascites or a solid tumour, and can be grown in vitro as a suspension culture (doubling time about 18 hours). One hundred cells kill an animal after i.p. transplantation, while 1,000 cells kill an animal after s.c. transplantation. Histopathological examination combined with TEM shows that SL2 metastasizes rapidly, especially after i.p. injection. The metastasizing cells reach the blood vessels in the lung septa and extravascular positions in the liver.

Animals↗
PubMed1982

The induction of lymphocytes with the capacity to render macrophages cytotoxic in an allogeneic murine system.

Sensitized spleen and peripheral lymph node lymphocytes were tested after different types of immunization with allogeneic tumour cells for their capacity to induce macrophage cytotoxicity in vitro. The macrophages were rendered cytotoxic either by direct contact with lymphocytes and tumour cells (activation of macrophages) or by a factor (macrophage arming factor, MAF), released by the sensitized lymphocytes incubated with tumour cells (arming of macrophages). Both types of reactions are T-cell dependent. Macrophage activation is a more sensitive way to detect lymphocytes with the capacity to render macrophages cytotoxic than arming of macrophages. The route of immunization subcutaneously (s.c.) or intraperitoneally (i.p.) with allogeneic cells did not influence the induction of lymphocytes with the capacity to render macrophages cytotoxic. However, the tumour cells had to be intact as disrupted cells (suspended in Freund's complete adjuvant, FCA) did not induce macrophages activating lymphocytes. The adjuvant dimethyl dioctadecyl ammonium bromide (DDA) did not increase the lymphocyte response. Intact allogeneic tumour cells were needed in vitro when used for secondary antigenic stimulation. This secondary stimulation was independent of antigen presentation by macrophages. This suggests that also in vivo the primary response is independent of macrophage antigen presentation. Delayed-type hypersensitivity and antibody responses against the allogeneic tumour cells were comparable after s.c. and i.p. immunization and after immunization with FCA and DDA.

Adjuvants, Immunologic↗
PubMed1982

Peritoneal cell populations during tumour injection.

The response of peritoneal cells to the SL2 lymphoma was studied in immunized and non-immunized mice to elucidate further the cellular events that lead to tumour rejection in an allogeneic and a syngeneic tumour system. Anti-tumor immunity was induced by intraperitoneal injection of normal, irradiated or mitomycin-C treated tumour cells. Four different immunization schedules were tested. The response of the peritoneal cells was investigated by studying the peritoneal cell population kinetics (appearance and/or disappearance of various cell types e.g. mononuclear phagocytes, lymphocytes, PMNS and mast cells). Total cell counts were done using phase contrast microscopy, differential cell counts were done on cytocentrifuge slides, stained with May Grünwald-Giemsa. The activity of the lysosomal enzyme beta-glucuronidase present in mononuclear phagocytes was also studied. The results indicated that the composition and morphology of the cellular fraction of the peritoneal exudate changes quite dramatically during tumour rejection. Especially the beta-glucuronidase activity of the mononuclear phagocytes line varies significantly. The observed changes in the cellular population depended upon the dose of tumour cells injected i.p. No significant differences were observed between the peritoneal cell populations of mice grafted i.p. with irradiated or with mitomycin-C treated tumour cells. On the other hand when mice previously immunized with three injections with 10 irradiated or mitomycin-C treated tumour cells were challenged i.p. with various doses of tumour cells, the immune potency against the tumour is greater after previous immunization with irradiated SL2 cells than after immunization with mitomycin-C treated tumour cells.

Animals↗
PubMed1981

Murine macrophage cytotoxicity induced by mastocytoma cells, cell-free mastocytoma exudates, and extracts.

Peritoneal macrophages obtained from normal CBA mice expressed significant cytotoxicity against the DBA/2-derived P815 mastocytoma but not against DBA/2-derived SL2 tumor or the C57BL-derived tumors TLX9 and EL4. The macrophages also expressed some cytotoxicity against the DBA/2-derived L5178Y tumor. Incubation of normal CBA macrophages with cell-free exudate of intraperitoneally growing P815 cells resulted in cytotoxicity against the SL2 and against the EL4 lymphosarcoma. Incubation of SL2 tumor cells with P815 ascitic fluid before adding the SL2 tumor cells to normal CBA macrophage monolayers also resulted in inhibition of SL2 tumor cell growth on these monolayers. Trypsinization of the macrophages after incubation with ascitic fluid (or tumor extract) but before challenge with tumor cells abolished cytotoxic activity of the macrophages. Incubation of normal macrophages with a comparable amount of trypsin before tumor cells were added had no influence on their activity. Cytotoxicity could be induced after 7 days storage of the exudate at 5 degrees C, but this ability was lost within 72 hr when kept at room temperature. Storage at -20 degrees C had no influence. Gel fractionation of the cell-free exudate showed that the product responsible for the effect is a small molecular weight product (mol wt less than 1000). Furthermore the "product" was dialyzable. The "factor" could not be shown in the supernatant of P815 cell cultures unless the cultures comprised greater than or equal to 40% dead cells.

Animals↗
PubMed1981

Destruction of murine lymphoma cells by allogeneic immune peritoneal macrophages in vitro: an ultrastructure study.

SL2 lymphoma cells from inbred DBA/2 mice were added to monolayers of peritoneal macrophages isolated from immunized inbred C57BL/10ScCr mice. Tumor cells were removed from the supernatant most rapidly during the first few hours. Once tumor cells were bound to the macrophages, however, their destruction apparently proceeded at a constant rate. Most tumor cells initially had only very small areas of contact with macrophages. The first tumor cell changes were loss of microvilli and the formation of surface blebs that ultimately detached from the cell. Subsequently, the tumor cell rapidly rounded up while the nucleus became pyknotic and the cytoplasm vacuolated; finally, the plasma membrane lost its integrity. It was only in this stage that the macrophages actively phagocytized the tumor cells. The recorded extracellular killing of tumor cells, followed by phagocytosis of their remnants, was compared with the widely divergent descriptions of macrophage-tumor cell interaction in the literature.

Animals↗
PubMed1980

Demonstration of migration inhibitory factor (MIF) in a murine system using myelomonocytic leukemia cells (WEHI-3).

Cells of the myelomonocytic tumor cell line, WEHI-3, were used as indicator cells in the indirect capillary test for the detection of migration inhibitory factor (MIF). A migration inhibition of about 50% was found and the results were highly reproducible. The indicator cells can be obtained in large quantities, as the myelomonocytic cells grow as an ascitic tumor in the peritoneal cavity of BALB/c mice.

Animals↗
PubMed1979

Natural cytotoxic macrophages in the peritoneal cavity of mice.

Many strains of mice from various breeding institutes have natural cytotoxic macrophages. These macrophages can also be present in nude mice, suggesting that this cytotoxicity can be acquired without invovlvement of T cells. The natural cytotoxicity was non-specific for tumour cells, was not sensitive to trypsin treatment, was lost after 5 days incubation, but could be enhanced by foetal bovine serum. The presence of cytotoxic macrophages in the peritoneal cavity was not genetically or age controlled. Natural cytotoxic macrophages did not occur in germ-free mice. The possible causes of natural cytotoxicity are discussed.

Animals↗
PubMed1979

Influence of whole body irradiation on intraperitoneal immunity in a syngeneic mouse lymphoma system.

DBA/2 mice were immunized against the syngeneic SL2 lymphoma by two injections with irradiated lymphoma cells or by two injections with irradiated cells followed by one injection with unirradiated cells. Whole body irradiation (500 rad) of the immunized mice caused a significant decrease in the number of peritoneal macrophages and lymphocytes. The spleen weight showed a transient decrease. However, whole body irradiation did not cause a significant decrease of the survival time of immunized mice challenged intraperitoneally with SL2 lymphoma cells.

Animals↗
PubMed1975

Therapy with antibody-coated immune and hyperimmune peritoneal cells in a murine lymphoma system.

Goat-antimouse (DBA/2) SL2 lymphoma immunoglobulin was specifically cytotoxic to DBA/2-derived sl2 lymphoma cells. This anti-SL2 immunoglobulin, or a part of it, was cytophylic for peritoneal macrophages as shown by target cells adhering to macrophages incubated in vitro with the immunoglobulin. The target cells became free in the medium after incubation with 0.1% trypsin for 1 hour. In in vivo experiments, the incubation of immune or hyperimmune peritoneal cells with immunoglobulin from normal goat serum or from goat-anti-SL2 serum before use in immunotherapy decreased the number of DBA/2 mice surviving for more than 35 days an intraperitoneal injection with SL2 cells compared to the number of survivors inoculated with immune or hyperimmune cells only. These results show that, in immunotherapy with immune cells, we must consider the possibility that specific antitumor antibodies and antibodies not directed against the tumor cloud the therapeutic potnecy of the immune cells.

Adsorption↗