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At least 37 records · Page 2Linked to original sources
PubMed1978

Cytotoxic T cell responses to a syngeneic tumour: conditions for primary activation in vitro.

Primary cytotoxic responses of DBA/2 lymph node cells to a syngeneic tumour (the mastocytoma P815) have been generated in vitro. The development of these responses is dependent on the addition of a soluble factor (CSCS) which is produced by concanavalin A-activated spleen cells. The response is mediated by T lymphocytes, can be detected at low effector to target cell ratios and is directed against P815 tumour-associated antigens.

Animals↗
PubMed1978

[Toxoplasmosis transmission by blood transfusion? (author's transl)].

T-cells of the chicken tumour HPRS-1, mouse mastocytoma cells, Friend virus-transformed erythroleukaemia cells as well as normal human, mouse and chick erythrocytes were tested for their receptivity to toxoplasma infection. The studies indicate that T-cells and mastocytoma cells, which may be counted as part of the white blood cell series, have the highest invasion rate after incubation with toxoplasma. Friend-erythroleukaemia cells were less often affected; mature human, mouse and chick erythrocytes were refractory. The results suggest that cells of the white blood cell series are receptive to toxoplasma infection but that nucleated precursors of the red series may also be so, while mature erythrocytes cannot be infected. The possibility of transmission of toxoplasmosis by blood transfusion can no longer be doubted.

Animals↗
PubMed1977

Dimeric immunoglobulin E serves as a unit signal for mast cell degranulation.

Rat immunoglobulin E (IgE) was treated with a crosslinking reagent, dimethyl suberimidate, and fractionated by gel filtration into monomers, dimers, trimers, and higher polymers. The fractions retained substantial ability to bind specifically to mast cells. About one-third of the cell-bound dimers appeared to bind bivalently. The fractions were assayed in vivo by passive cutaneous anaphylaxis in rats, and for histamine or serotonin release in vitro using normal or tumor mouse mast cells. The monomers showed no activity, while the dimers and higher polymers gave excellent and approximately equivalent responses. We conclude that IgE that has been crosslinked to form dimers prior to the addition to mast cells can serve as a unit signal for triggering IgE-mediated exocytosis.

Animals↗
PubMed1979

Leukotriene C: a slow-reacting substance from murine mastocytoma cells.

Murine mastocytoma cells treated with calcium ionophore A23187 produced a slow-reacting substance (SRS) that caused guinea pig ileum to contract. The response was reversed by the SRS antagonist FPL 55712. On the basis of isotope incorporation experiments, spectroscopy, and chemical degradations, the SRS was identified as a cysteine-containing derivative of 5-hydroxy-7,9,11,14-icosatetraenoic acid. This amino acid was attached in thioether linkage at C-6. The SRS is structurally related to previously identified epoxy and dihydroxy metabolites of arachidonic acid in leukocytes. A common feature is the presence of a conjugated triene, and the name "leukotriene" has been introduced to designate these compounds. Leukotriene A (5,6-epoxy-7,9,11,14-icosatetraenoic acid) is an intermediate in the formation of leukotriene B (5,12-dihydroxy-6,8,10,14-icosatetraenoic acid) and is proposed to be a precursor also of leukotriene C, which is the SRS identified here.

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PubMed1976

Potentiation of cytotoxic T-cell function by virus.

Inoculation of C57BL/6J mice with allogeneic P815 mastocytoma cells in the presence of simian virus 40 (SV40), a DNA tumor virus, led to an enhanced cytolytic T-cell response to P815 in vivo. Cytotoxic function was also augmented if SV40 was given subsequent to a primary immunization, even when mice were given a suboptimal dose of immunizing cells. Although SV40 increased the cell-mediated immune response to allogeneic cells, it did not enhance the antibody response to the soluble antigen dinitrophenyl bovine gamma-globulin, a helper T-cell-dependent response. Thus it appeared that SV40 had a selective adjuvant effect on lymphocyte subpopulations, since it increased cytotoxicity but not helper T-cell function.

Animals↗
PubMed1977

Antigenic changes of DBA/2J mastocytoma cells when grown in the BALB/c mouse.

A 10-day growth period of the DBA/2J strain-specific P815-X2 mastocytoma in the BALB/c mouse altered the antigenicity of the tumor cell surface. The in vivo-modified mastocytoma cells differed from mastocytoma cells grown in the original DBA/2J mice in suspectibility to lysis by immune peritoneal exudate cells, in vitro antigenic recognition by cytotoxic T-cells, and immunizing capacity in allogeneic C57BL/6 mice. Propagation of the altered tumor cells in the original host or maintenance in tissue culture for 40 hours restored complete susceptibility to lymphocyte-mediated cytotoxicity.

Animals↗
PubMed1978

Isotope-release cytotoxicity assay with the use of indium-111: advantage over chromium-51 in long-term assays.

The adaptation of indium-111-oxine (also known as 8-hydroxyquinoline) (111In Ox) chelate for long-term (18-48 hr) isotope-release assays of cell-mediated cytotoxicity (CMC) and its advantages over the use of 51 Cr are described. Labeling of DBA/2 P815 mastocytoma cells with 111InOx resulted in the incorporation of as many as a million counts per minute in 10(5) cells with no reduction in cell viability. 111InOx labeled both mouse and human tumor cells. 111InOx, like 51Cr, primarily labeled cytoplasmic constituents; up to 80% of the label existed in a releasable form. 111InOx was quantitatively released from labeled P815 in response to specifically sensitized C57BL/6 lymphocytes. The high labelling efficiency of 111InOx offered a significant advantage over 51Cr in 18- to 48-hour assays for CMC by reducing the counting error and thus making the assay more precise. Because of its higher labeling efficiency, 111InOx can be used in microcytotoxicity assays. 111InOx has the added advantage of a lower spontaneous release in culture than 51Cr. This feature of 111InOx also makes the calculation of specific isotope release more accurate than that achieved with 51Cr in long-term cytotoxic assays.

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PubMedDate not supplied

Localization of 99mTc-labeled immune splenocytes at tumor site and detection by gamma camera imaging.

Better diagnostic techniques are needed to delineate the size and location of malignant primary tumors and metastatic deposits. We are developing an in vivo tumor visualization technique utilizing 99mTc-labeled immune lymphoid cells. We have investigated the in vivo organ and tissue distribution and tumor localization of 99m sodium pertechnetate, 99mTc, reduced by SnCl2 - 2H2O and 99mTc-labeled viable immune and nonimmune lymphocytes 32 hrs after injection into tumor-bearing mice. The distribution and tumor localization of the 99mTc-labeled compounds and splenocytes within tumor-bearing mice after 32 hrs was determined by imaging with a gamma camera and was quantitated by counting the various dissected organs and tissues in a gamma counter. The gamma camera images and postmortem dissection and counting showed localization of radioactivity at several sites, including the tumor in mice injected with radiolabeled immune splenocytes whereas studies utilizing other 99mTc-labeled substances or nonimmune cells showed little or no localization of radioactivity in the tumor when compared to normal leg tissue.

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PubMed1975

Antibody-dependent cell-mediated cytotoxicity: heterogeneity of effector cells in human peripheral blood.

We have compared antibody-dependent cell-mediated cytotoxicity (ADCMC) of human peripheral blood leukocytes (PBL) in three model systems. target cells were 51Cr-labeled mouse mastocytoma cells, chicken erythrocytes (CRBC), and human erythrocytes (HRBC) coated with appropriate heterologous or isologous antisera. Effector cells were characterized on the basis of their adherence, phagocytosis, radiosensitivity, and sedimentation velocity(s) at 1 g. In predominantly mononuclear (Ficoll-Isopaque-purified) PBL preparations (MPBL) HRBC were lysed by an adherent, phagocytic population of cells that was markedly radio-resistant. Sedimentation velocity analysis further established that these effector cells were restricted to rapidly sedimenting fractions (s greater than 4.5 mm/hr). On the other hand, mastocytoma cells were lysed by a population of MPBL that was nonadherent, nonphagocytic, and relatively radiosensitive. These cells mainly restricted to slowly sedimenting fractions (s greater than 4.5 mm/hr) following 1 g velocity sedimentation. CRBC appeared to be susceptible to lysis by both types of mononuclear effector cell. In some experiments, enriched populations of polymorphonuclear leukocytes (PMN) were isolated. These cells were found to lyse both HRBC and CRBC very efficiently, whereas mastocytoma cells were lysed very little if at all by the same effector populations. Taken together, these results suggest that antibody-coated mastocytoma cells are lysed uniquely by effector cells in human peripheral blood with the physical properties of lymphocytes, whereas antibody-coated HRBC are lysed by both monocytes and PMN, but not by lymphocytes. Antibody-coated CRBC would appear to be lysed by all of the three effector cell types tested.

Animals↗
PubMed1978

Adjuvant activity of synthetic 6-O-"mycoloyl"-N-acetylmuramyl-L-alanyl-D-isoglutamine and related compounds.

Adjuvant and antitumor activities of synthetic 6-O-"mycoloyl"-N-acetylmuramyl-L-alanyl-D-isoglutamine were examined. All the synthetic 6-O-corynomycoloyl-, 6-O-mocardomycoloyl-, and 6-O-mycoloyl-N-acetylmuramyl-L-alanyl-D-isoglutamine were active as adjuvants for cell-mediated immune responses. However, 6-O-mycoloyl-N-acetylmuramyl-L-alanyl-D-isoglutamine was less active as an adjuvant on circulating antibody formation. It was shown that pyrogenic activity of N-acetylmuramyldipeptide was reduced by 6-O-acylation with mycolic acid, but not with nocardomycolic or corynomycolic acid. Tumor-suppression activity was observed by the synthetic 6-O-mycoloyl-N-acetylmuramyl-L-alanyl-D-isoglutamine by using transplantable tumor in syngenic mice.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1978

Effects of the epipodophyllotoxin derivative VM 26 in mitosis and in interphase.

The epipodophyllotoxin derivative VM 26 inhibits entry of mouse mastocytoma cells into mitosis in cell cultures at drug concentrations of 0.01--1 microgram/ml, the cells being arrested in G2 phase of the cell cycle. At higher concentrations, the compound exhibits spindle poison activity which manifests itself in a shortlasting rise in the number of cells arrested in metaphase of mitosis. These cells then disintegrate after a short period of time.

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