Molecular and quantitative analysis of helper T cell-replacing factors on the induction of antigen-sensitive B and T lymphocytes.
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Animals↗
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Results for “Mast-Cell Sarcoma”
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Accessory cell requirements for the generation of cytolytic T lymphocytes.
A system is presented that may simplify the study of accessory cell requirements for CTL generation. Cortisone resistant (CR) thymocytes containing alloreactive CTL precursors do not respond to allogeneic tumor cells unless non-T accessory cells are added to culture. In addition, splenic T cells do not respond to allogeneic tumor cells in the absence of non-T accessory cells. These accessory cells share several properties of macrophages.
Animals↗
[Morphological analysis of spontaneous hemoblastoses in dogs and cats].
Information of the frequency and morphological characteristics of spontaneous hemoblastoses in dogs and cats observed in 1966-1978 are presented. Hemoblastoses were diagnosed in 90 dogs and 12 cats. Lymphoproliferative diseases were most frequent: lymphosarcomas (80 cases) and lymphocytic leukemias (11 cases). Ten dogs had mastocytomas and one--myeloid leukemia. The cell composition of the organs and tissues involved permitted to distinguish 3 cellular variants of lymphosarcoma: poorly differentiated, lymphoblastic, and prolymphocytic; in both species the poorly differentiated type of lymphosarcoma was predominant (47 cases). It is recommended to use spontaneous hemoblastoses of dogs and cats as an experimental model for investigations of the pathogenesis and therapy of human leukemias.
Animals↗
Modulation of natural cytotoxicity by alloantibodies. I. Alloantisera enhancement of cytotoxicity of mouse spleen cells toward a human myeloid cell line.
Natural killer activity of spleen cells obtained from different strains of mice against the human myeloid leukemia cell line, K562, and two mouse cell lines P815 and L1210 was measured by using the 4-hr chromium release assay. The level of cytotoxic activity of spleen cells against the K562 target was usually less than 4% lysis. However, treatment of the spleen cells with a specific anti-H-2 antiserum resulted in a dose-dependent augmentation of the degree of lysis of K562 cells. The augmentation of cytotoxic activity could be obtained by pretreatment of the spleen cells with antisera or by directly adding the antisera to the cytotox-incubation medium. Anti-thy-1 and anti-immunoglobulin antisera had no enhancing effect under similar conditions. The specific alloantisera-treated spleen cells did not show any increase in cytotoxicity against P815 and L1210 target cells. Spleen cells responsible for the alloantiserum-mediated augmentation of cytotoxicity against K562 cells appear to be different from T or B cells as indicated by their resistance to anti-thy-1 and complement treatment and lack of adherence to nylon wool columns.
Animals↗
Competitive inhibition of cytotoxic T lymphocyte-target cell conjugation. A direct evaluation of membrane antigens involved in cell-mediated immunity.
A method to determine directly the antigenic similarity of target cells (TCs) involved in cytotoxic T lymphocyte (CTL)-TC interactions is described. When fluorescently labeled TC (FL-TCs) are bound (conjugated) to CTLs in the presence of antigenically similar but unlabeled TCs, the percentage of CTL-TC conjugates containing unlabeled TCs corresponds linearly to the number of unlabeled TCs in the TC population. This assay is specific, permits direct observation of individual CTLs and TCs which interact to form conjugates, can be completed within 10 min, eliminates complications attributable to CTL recycling, and the degree of competition observed fits that theoretically expected. The results of this paper provide the theoretical basis for "cold" (unlabeled) target inhibition of radioactive assays of lymphocyte-mediated cytolysis.
Animals↗
Non-immunological cell death of intravenously injected murine tumour cells.
Most DBA mastocytoma and Sarcoma 180 cells trapped in the lungs of mice after i.v. injection died within 7 h. Rates of cell death were similar for both tumour cell lines. Rates of tumour cell death were unrelated to whether the cells were allogeneic or syngeneic, induced platelet aggregation or not, had different patterns of subsequent tumour growth, or were injected in varying numbers. Cell death was by coagulative necrosis, not apoptosis. Sarcoma 180 tumour cells were quickly localized in the lung and enclosed in platelet aggregates which remained, with degranulation, until the time of tumour cell death. However, platelet aggregation did not appear to play a role in tumour cell killing. The prevention of platelet aggregation by pretreatment of mice with an anticoagulant had little effect on the rate of death of tumour cells in the lung. Mastocytoma tumour cells did not cause platelet aggregation, yet died in the lung at similar rates to Sarcoma 180 cells. The killing of tumour cells in the lung did not appear to be cell-mediated. No mononuclear cells were seen in the vicinity of tumour cells and the type of cell death was not that associated with cell-mediated killing. The tumour cells did not die within 6 h of being injected into the peritoneal cavity. It is suggested that a nonspecific non-immunological process results in the death of intravenously injected tumour cells in the lung. This process was not affected by differing oxygen levels in the inhaled gas.
Animals↗
The mechanism of T-cell mediated cytotoxicity. VII. Lysis of isolated cytoplasts and karyoplasts.
Isolated P815 karyoplasts are up to four times more susceptible to lysis by T cells than intact cells, suggesting that the target cells nucleus or a nuclear associated structure may be particularly sensitive to cell-mediated cytotoxicity. Cytoplasts showed variable susceptibility. The morphological changes seen by time-lapse cinematography show that the first change seen with intact cells is a burst of zeiosis (membrane blebbing), whereas neither cytoplasts nor karyoplasts exhibit zeiosis. These observations suggest that zeiosis results from changes in the cytoskeletal system. This is discussed in relation to the possibility that T cells kill target cells by causing physical damage to a critical organelle inside the cell rather than to the membrane itself.
Animals↗
Growth enhancement and serum replacement in cloning of murine mastocytoma and granulocyte/macrophage precursor cells: two distinct activities present in hemolysates.
In the present study we investigated the serum replacing and enhancing activities of erythrocyte lysates, obtained from different animal species, on the growth of murine mastocytoma cells and normal granulocyte/macrophage precursor cells (CFU-C) present in bone marrow. The soft agar technique for cloning hemopoietic cells in vitro was used to quantitate the growth of these cells in culture. Rat, rabbit, guinea pig, mouse and sheep hemolysates were tested for their capacity to replace or to enhance serum as a growth promoter. All hemolysates except mouse were able to replace serum efficiently when mastocytoma cells were cloned. On the other hand, only rat hemolysate proved to be efficient for cloning normal murine CFU-C. Since increasing the concentration of hemolysates in the soft agar medium did not change these results, the differences in activity are unlikely to reflect quantitative variations. However, hemolysates with little or no serum replacing capacity enhanced the clonal growth of normal CFU-C when added to small amounts (2.5%) of horse serum. Trypsin treatment of rat hemolysate destroyed its serum replacing capacity but not its enhancing activity. No correlation was found between the amount of hemoglobin and the replacing activity of each hemolysate. The data obtained in the present study point to the presence of at least two distinct activities in hemolysate: serum replacing and growth enhancing capacities.
Animals↗
MICC cytotoxic effector function of human T lymphocyte subpopulations bearing Fc-receptors for IgG and IgM.
Purified subpopulations of human T lymphocytes bearing Fc-IgG and Fc-IgM receptors were studied for their ability to mediate mitogen (PHA) induced cellular cytotoxicity (MICC) to chicken erythrocyte (CRBC) and DBA/Mastocytoma P815Y tumour cell targets. There were marked differences in the ability of the Fc-IgG receptor-bearing T cell (T gamma) and the Fc-IgM (T mu) to mediating MICC to CRBC and P815Y target cells. T gamma cells were very efficient killers of CRBC and T mu cells had no cytotoxic activity to CRBC. On the other hand, both the T gamma and T mu subpopulations were able to mediate MICC to P815Y tumour cell targets.
Cytotoxicity, Immunologic↗
[A case of mastocytoma with leukemic manifestation of its immature form in the terminal stage (author's transl)].
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Adult↗
The occurrence of a bilateral mandibular mast cell neoplasm in a mouse with lymphocytic leukemia.
A 7-month-old female mouse was killed after developing lethargy, rough hair coat and enlarged superficial lymph nodes. Postmortem and histologic examination revealed lymphocytic leukemia involving several organs and a bilateral mast cell neoplasm in the mandible.
Animals↗
[General facts on mastocytoma in the dog. Apropos of the first Tunisian case].
After anatomo-pathologic, épidemiologic and etiopathogenic description of canine Mast-cell tumor, the authors insist on the importance of this neoplasm in comparative pathology. Such animal model observation can be eventually used both in cancer Research and in allergo-dermatology.
Animals↗
Macrophage cytotoxicity in the mouse immune response against a skin allograft.
Macrophage-rich peritoneal cell populations from C57BL/6 mice grafted with DBA/2 skin were found to be cytotoxic against 51Cr-labeled target cells from the donor strain. Normal peritoneal macrophages were also rendered cytotoxic by incubation with acellular supernatants of mixed lymphocyte cultures (MLC) between an allograft recipient and a donor mouse. Supernatants alone were not cytotoxic. The macrophage arming factor(s) was found in supernatants when the MLC was performed after more than 6 to 9 days following grafting. In order to produce MAF, sensitized lymphocytes must usually be stimulated in a specific way by donor type cells. The armed macrophage cytotoxicity was, however, not found to be specific in these experiments.
Animals↗
Studies on the synthetic capacity and antigenic expression of glutaraldehyde-fixed target cells.
Mastocytoma cells (P815 of the DBA/2 strain) treated with increasing concentrations of glutaraldehyde were concurrently evaluated for their ability to incorporate exogeneous uridine, thymidine, and amino acids. The antigenic expression and membrane integrity of these treated cells were assayed by measuring their susceptibility to lysis by antibody and complement and by T-effector cells. The concentrations of glutarladehyde required to effect target cell antigen display were greater than those required to inhibit totally the cell's protein and nucleic acid synthetic processes. Thus, P815 cells treated with 0.15% glutaraldehyde for 10 sec were unable to incorporate either amino acids or nucleotides into macromolecules, but were readily lysed by effector T cell populations, and by alloantibody in the presence of complement. Target cells treated with glutaraldehyde concentrations in excess of 0.25% for 10 sec were resistant to both forms of immune lysis. In keeping with these observations, monolayers of P815 cells treated for 10 sec with 0.15% glutaraldehyde, were capable of specifically depleting T-effector cells from a cytolytically-active spleen cell population. After treatment with higher concentrations of glutaraldehyde (0.3%), however, the monolayers lost their capacity to adsorb effector cells. Although P815 cells treated with glutaraldehyde continued to exhibit H-2d alloantigen, neither these cells nor glutaraldehyde-treated DBA/2 spleen cells induced significant blastogenesis or stimulated the production of cytolytically active effector cells in mixed leukocyte cultures.
Adsorption↗
Alloimmune cytotoxic T cells: Evidence that they recognize serologically defined antigens and bear clonally restricted receptors.
Murine T cells immunized with allogeneic cells exert a cytotoxic effect on appropriate target cells, as measured by 51-Cr release. Lysis of the 51-Cr-labeled target can be inhibited by addition to the assay of unlabeled cells which bear target antigens. With variants of lymphoid tumors which express different amounts of serologically defined H-2 antigens as competitors in the assay, a positive correlation is shown to exist between the amount of serologically defined antigen and the degree of inhibition of T cell-mediated lysis. The immunized small lymphocytes are shown to be very poor inhibitors of 51-Cr release from target cells which are more susceptible to T cell-mediated lysis. This is interpreted as showing that small lymphocytes are bound very poorly by cytotoxic T cells. With H-2 cross-over strains which carry only the H-2K or H-2D antigens which a cytotoxic population is directed against, it is shown that, 1) approximately equal amounts of cytotoxicity are directed against the K and D antigens, and 2) separate cytotoxic T cells recognize the K and D antigens. Thus, by this criterion, cytotoxic T cells are monospecific and therefore do not acquire their antigen-specific receptors cytophilically.
Animals↗
[Incapacity of 5-hydroxytryptophan to act against the depression of tumor-resisting power of host animal which is induced by whole body x-irradiation].
The effect of L-5-hydroxytryptophan (L-5-HTP) against the depression of tumor-resisting power in host animal, which is induced by a whole body x-irradiation of 500 R, was studied. Host animal and tumor cell used were LAF, hybrid mouse and mastocytoma cell, respectively. The i.p. injected dose of L-5-HTP was 6.25 mg per mouse, which is most effective for protecting mice from radiation-induced hematopoietic death. In the experimental conditions, the agent was not effective to prevent the radiation-induced depression of tumor-resisting power of the animal.
5-Hydroxytryptophan↗
Generation of cytolytic T lymphocytes in vitro. VIII. failure of anti-RS antisera to inhibit the generation of cytolytic T lymphocytes or cytolytic T lymphocyte activity.
Antibody reactive with "recognition structures" (RS) of mouse lymphoid cells for alloantigens (anti-RS) was prepared by immunization of F1 hybrid mice with parentalstrain lymphoid cells or with antibody produced in one parental strain against alloantigens of the other parental strain. Such antisera prevented generation of the "product of antigenic recognition" (PAR) that is produced within a few hours in cultures prepared with a mixture of lymphoid cells from genetically disparate mice. However, treatment of responding lymphoid cells with anti-RS sera and complement did not inhibit generation of cytolytic T lymphocytes (CTL) in mixed lymphocyte cultures (MLC). Treatment of cells obtained from MLC with anti-RS sera and complement failed to inhibit cytolytic activity of such cells for specific alloantigens.
Animals↗