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Results for “Mast-Cell Sarcoma”

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At least 199 records · Page 11Linked to original sources
PubMed1979

Selective depression of the xenogeneic cell-mediated lympholysis in systemic lupus erythematosus.

The immunological responsiveness of a panel of 17 patients with systemic lupus erythematosus (SLE) was studied in an in vitro model of xenogeneic sensitization against mouse lymphoid cells. Generation of cytotoxic thymus-derived (T) cells evaluated by a chromium release assay against labeled target cells was found to be drastically impaired in these lupus patients. Such depression was independent of drug therapy at the time of the study, clinical status, and other immunological parameters such as antibodies against native DNA, complement levels, cryoglobulinemia, circulating immune complexes, or T- and bone marrow-derived (B)-cell numbers. In contrast to the cytotoxic response, the proliferative responses to phytohemagglutinin, to allogeneic lymphocytes, and to xenogeneic lymphocytes were not significantly different from those of normal individuals. The latter response was shown to be H-2 restricted with the primed lymphocyte test. These results suggest the presence of a selective defect in the generation or in the expression of killer cells rather than a deficiency in antigen recognition by T cells. The role of serum factor(s) was examined by educating the lymphocytes of normal subjects in the presence of serum from SLE patients. Such manipulation affected both the generation of killer cells and the proliferative response. Finally our observations indicate that depression of cell-mediated immunity in SLE patients may be associated with several mechanisms including a cellular one, specifically affecting the generation of killer T cells, and a humoral one possibly as a result of antilymphocytic antibodies and(or) immune complexes.

Adult↗
PubMed1978

Focal mastocytosis in lymph nodes from a Beagle dog.

An 11-year-old Beagle dog had focal mastocytosis in the midtracheobronchial and left tracheobronchial lymph nodes. The cells were well-differentiated and were arranged in well-defined follicles. There were neither skin tumors nor mast-cell accumulations in other tissues.

Animals↗
PubMed1979

Cytology of canine cutaneous round cell tumors. Mast cell tumor, histiocytoma, lymphosarcoma and transmissible venereal tumor.

Sixty-four canine cutaneous round cell tumors were divided into 25 mast cell tumors, 15 histiocytomas, nine cutaneous lymphosarcomas and 15 transmissible venereal tumors. The final diagnosis was made from cytologic, clinical and histologic findings. Cytologic features were significantly distinctive in mast cell tumor, transmissible venereal tumor, and most cases of histiocytoma and lymphosarcoma to allow a diagnostic opinion. This opinion was supported by subsequent histologic examination. In some instances cytology was considered essential in rendering a diagnostic opinion even though histology was available.

Animals↗
PubMed1979

The mechanism of K-cell (antibody-dependent) mediated cytotoxicity. III. The ultrastructure of K cell projections and their possible role in target cell killing.

The cytotoxic interaction between lymphoid K cells from normal rat spleen and antibody-coated P815 mastocytoma cells has been studied in conditions under which the number of cytolytic events occurring at the time of observation was at a maximum. Electron micrographs of material fixed during the first 15 min after contact between the target and effector cells had been initiated by centrifugation showed that the K cells produce long projections which push deeply into the P815 cells, causing infoldings of the plasma membrane and distortion of the nucleus. The plasma membranes of the effector and target cells, and the nuclear membrane, remain intact. Subsequently the target cells undergo violent cytoplasmic blebbing (zeiosis) which is the first stage of cell lysis. The evidence for the hypothesis that projections from lymphoid K cells develop as a result of contact between receptors on the K cell surface and antibody bound to the target cell, and that the projections are involved in the cytotoxic mechanism is discussed.

Animals↗
PubMedDate not supplied

[Sequence complexity of transcribed unique DNA sequences in genome of mouse P815 mastocytoma cells (author's transl)].

The sequence complexity of nuclear RNA from mouse liver, mouse spleen and highly malignant P815 mastocytoma was measured by nRNA driven hybridization to unique DNA sequences of P815 cells. The unique DNA sequences represent 63% of the total nuclear DNA of P815 cells and their availibility in hybridization experiments was found to be 76%. Of these sequences 7.8% formed hybrids with nuclear RNA of this cell, about 11.5% with mouse spleen and about 14.5% with mouse liver nuclear RNA. Assuming an asymmetrical transcription, the complexities of these transcripts are 2.8 X 10(8) nucleotides for mouse P815 mastocytomas, 4.3 X 10(8) for mouse spleen and about 5.3 X 10(8) nucleotides for mouse liver. Cellular specifity of the transcribed information was analyzed in additivity experiments, in which unique DNA sequences, not complementary to the nuclear RNA of one cell were annealed to the nuclear RNAs of the two other tissues/cells. In these experiments most of the nuclear RNA sequences of P815 cells were found to be also present in the nucleus of mouse liver and spleen. Only a small portion of the unique DNA sequences of P815 mastocytoma (about 1.2% corresponding to 4.4 X 10(7) nucleotides) was found to be complementary only to P815 mastocytoma nuclear RNA.

Animals↗
PubMed1977

Arming of macrophages with lymphocytes from mice immunized with tumor tissue.

C57BL/6 macrophages are rendered specifically cytotoxic ("armed") by incubation with spleen cells from C57BL/6 mice sensitized in vivo with allogeneic P-815 mastocytoma cells. Data are presented which suggest that the cytotoxic activity of the macrophages is not due to the adherence of sensitized lymphocytes. The results indicate that it is the T-lymphocyte which is primarily involved in arming. Furthermore it is the cytotoxic and not the proliferating T-cell which is responsible for arming.

Animals↗
PubMed1978

The decay of memory of cell-mediated cytotoxicity after primary sensitization in vivo against a tumor allograft.

The length of time mice were able to show a secondary cell-mediated response after a tumor allograft was investigated. C57B1/6 mice were inoculated ip with P-815 mastocytoma cells and, at selected time intervals up to 12 months after immunization, spleen cells were placed in JLC in an attempt to generate secondary CTL activity. It was found, as measured by the 51Cr-release assay, that all mice tested had significant secondary CTL activity 3 months after allograft. The ability to generate a secondary response then decreased with considerable individual variation up to 6 months post-immunization. No significant difference in CTL activity was found between immunized and age-matched control mice 12 months after tumor allograft.

Animals↗
PubMed1979

Temporal specificity of procarbazine in the inhibition of mouse immune responses to allogeneic tumor.

The inhibition of the cellular response of C57Bl/6 mice against allogeneic P815 mastocytoma by procarbazine was shown to be uniquely dependent upon time of administration with respect to antigen. If the drug was given 4 or 6 days after antigen, the development of the T cell effectors was inhibited; if it was given earlier (2 hr or 1 or 2 days after antigen), the response was affected less. In contrast to the immunosuppressive effectiveness of delayed administration of procarbazine, the inhibition of the T cell response by daunorubicin was greatest when the agent was given 2 days after antigen, and that by cyclophosphamide, at the concentrations used, was relatively time independent. Under similar conditions the effects of the three agents on the humoral response were found to be less selective. The inhibition of both responses by procarbazine was shown to be dose dependent and relatively independent of the route of administration.

Animals↗
PubMed1975

Mastocytoma-induced suppression of in vitro antibody formation.

Mastocytoma cells in vitro suppressed the immune response of normal syngeneic spleen cells to sheep erythrocytes. The immune response of dispersed spleen cells from normal mice in vitro was inhibited by simultaneous incubation with relatively small numbers of mastocytoma cells or a cell-free extract prepared from these cells. Inhibition occurred when diluted cell-free extracts from the mastocytoma cells or as few as 10-4 or 10-5 tumor cells were incubated with 5 million normal splenocytes. The supernatant factor from mastocytoma cells was labile to heating at 56 degrees for 30 min. Detailed examination of the physicochemical properties of the mastocytoma cell extract capable of suppressing immune responses to sheep red cells should be of value.

Animals↗
PubMed1978

Estimates of the precursor frequency of cytotoxic T lymhocytes against antigens controlled by defined regions of the H-2 gene complex: comparison of the effect of H-2 differences due to intra-H-2 recombination vs mutation.

Lymph node cells were sensitized in a limiting dilution assay against B10.D2 (H-2d) and the frequency of cytotoxic T lymphocyte (CTL.P) precursors was determined. A mean CTL.P frequency of 0.047% was observed when responding strains differed from the stimulators at the entire H-2 gene complex. When intra-H-2 recombinant strains were sensitized against B10.D2, lower frequencies of CTL.P were observed. Responding strains that differed from the stimulators at the H-2K-end only had 2- to 6-fold more CTL.P compared to strains sensitized against the D-end only. In order to study the CTL.P frequency against minor antigenic differences, the B10.D2 (M504-H-2da) mutant strain, which carries a mutation with an antigenic gain-loss in the D-region of H-2d, was examined. This mutant showed an identical CTL.P frequency against H-2d as H-2D-end recombinant strains. Therefore, this H-2 mutant (M504) has either undergone extensive mutation or the qualitative nature of the antigenic loss in this strain results in a high CTL.P frequency against the strain of origin.

Animals↗