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PubMed1979

A high frequency of cytotoxic precursor cells for a syngeneic tumour.

The average frequency of cytotoxic precursor cells in DBA/2 lymph node cell preparations reactive to the syngeneic tumour P815 has been determined as 1 in 2000. This frequency is similar to the precursor frequency for an allogeneic tumour EL-4. The normal lack of response of DBA/2 lymph node cells to the syngeneic tumour P815 in vitro cannot be attributed to a lack of cytotoxic precursor cells. We conclude that in this tumour-host system non-immunogenicity reflects a defect at the inductive step.

Animals↗
PubMed1975

Interaction of histamine H1-and H2-receptor antagonists with histamine uptake and metabolism by guinea-pig isolated atrium and mouse neoplastic mast cells cells in vitro.

1. Burimamide, metiamide, chlorpheniramine, triprolidine and cocaine, were tested as inhibitors of histamine uptake and metabolism in the guinea-pig atrium and in mouse neoplastic mast cells. 2. Cocaine did not affect the uptake and metabolism of histamine, either in the atrium or in the mast cells. All the antihistamines tested blocked the uptake and metabolism of histamine in both preparations. The order of potency was burimamide greater than chlorpheniramine greater than triprolidine greater than metiamide in the atrium; and burimamide greater than metiamide greater than triprolidine greater than chlorpheniramine, in the mase cells. 3. Comparison of the present results with the antihistamine activity of these blocking agents suggests that no correlation exists between the receptor blocking activity and the ability of these substances to act as inhibitors of histamine uptake and metabolism.

Animals↗
PubMed1975

Ultrastructural characteristics of mast cells from a canine mastocytoma maintained in vitro.

Mast cells obtained from a canine mastocytoma were maintained in cell culture for a period of 11 weeks. Samples of these cells were harvested for electron microscopic examination after 9 weeks in vitro. Although the overall morphologic appearance was sufficient to allow their identification as mast cells, the tumor cells differed in several respects from descriptions of normal tissue mast cells. In contrast to normal tissue mast cells, the tumor cells exhibited peripheral accumulations of microfilaments, randomly dispersed microtubules, and small clusters of smooth endoplasmic reticulum. The tumor mast cells also presented three different granule types: spherical granules with an amorphous and electron dense matrix; irregularly shaped granules possessing a limiting external membrane and an internal matrix containing laminated and/or coiled structures; and granules containing loosely coiled, unorganized membrane structures similar in appearance to myelin whorls. The canine mastocytoma is an excellent source of mast cells as they can be obtained in large numbers without contamination by extraneous cell types and the cells can be maintained in vitro for extended periods of time.

Animals↗
PubMed1976

Immunotherapy of cancer with cell wall skeleton of Myocabacterium bovis-Bacillus Calmette-Guérin: experimental and clinical results.

Adjuvant and antitumor activities of CWS prepared from cells of mycobacteria, nocardia, and corynebacteria were examined. Oil-attached CWS of M. bovis BCG (BCG-CWS) stimulated the generation of cell-mediated cytotoxic effector cells in mice. Tumor growth was suppressed in mice inoculated intradermally with a mixture of oil-attached CWS and living tumor cells. Systemic and specific tumor immunity was demonstrated in mice in which tumor growth was suppressed. Tumor growth was also suppressed by oil-attached CWS of BCG or N. rubra in autochthonous autografts of spontaneous mammary adenocarcinoma and methylcholanthrene-induced fibrosarcoma in mice. The intravenous injection of oil-attached BCG-CWS prevents the appearance of lung cancer in rabbits by the instillation of chemical carcinogens. It was also shown that treatment with oil-attached BCG-CWS was able to elevate the immunologically depressed state of tumor-bearing mice to a normal level, as determined by a cell-mediated cytotoxicity assay that empolyed chromium release as the standard. Preliminary results suggest that oil-attached BCG-CWS is useful as an immunotherapeutic agent for both lung cancer and for malignant melanoma, leukemia, Hodgkin's disease, and other neoplastic diseases and that this agent operates without any significant complications.

Animals↗
PubMed1979

Stress and coping factors influence tumor growth.

Growth of syngeneic P815 mastocytoma in DBA/2J male mice was evaluated as a result of various stress regimens. A single session of inescapable shock resulted in earlier tumor appearance, exaggeration of tumor size, and decreased survival time in recipient animals. Escapable shock had no such effects. The effects of the inescapable shock were mitigated if mice received long-term shock treatment.

Animals↗
PubMed1975

T lymphocyte function as the principal target of lymphocytic choriomeningitis virus-induced immunosuppression.

Plaque-forming cell responses against sheep erythrocytes, Escherichia coli lipopolysaccharide, pneumococcal polysaccharide, and polyvinylpyrrolidone were examined in mice infected with lymphocytic choriomeningitis virus. A 92 to 96 percent reduction of the thymus-dependent anti-sheep erythrocyte responses was observed 2 to 4 weeks after infection. However, the thymus-independent responses against the three other antigens were close to normal at all stages of the infetion. Studies on allograft immunity of infected C3H mice against DBA/2 mastocytoma cells revealed a severe suppression of the T cell-mediated cytotoxic response which was temporally related to the impaired humoral responsiveness against sheep erythrocytes. The capacity of spleen cells from infected mice to restore immune responsiveness of lethally irradiated recipients against sheep erythrocytes was significantly reduced. The adoptive responses, however, were clearly improved when normal thymus cells were added to the inferior spleen cells. Moreover, it appeared that the spleen cells from immunosuppressed donor mice could not confer suppression to normal lymphoid cells. The presented findings are consistent with the assumption that a numeric deficiency of T cells, or cells belonging to some T cell subpopulation, is the primary cause of lymphocytic choriomeningitis virus-induced immunosuppression.

Animals↗
PubMed1976

Adjuvant activity of mycobacterial fractions: adjuvant activity of synthetic N-acetylmuramyl-dipeptide and the related compounds.

Immunological activity of synthetic cell wall peptidoglycan subunits was examined in guinea pigs and mice. It was concluded that the minimal adjuvant-active subunit of cell wall peptidoglycan for the induction of delayed-type hypersensitivity to monoazobenzenearsonate-N-acetyl-L-tyrosine and for circulating-antibody formation to bacterial alpha-amylase and the thymus-independent antigen DNP-Ficoll was N-acetylmuramyldipeptide, MurNAc-L-Ala-D-isoGln. N-acetylmuramyldipeptide and 6-O-stearoyl-N-acetylmuramyldipeptide showed no adjuvant activity in the generation of cell-mediated cytotoxic effector cells in the spleens of C57Bl/6J mice after in vivo immunization with the allogeneic antigen mastocytoma P815-X2 cells, but N-acetylmuramyldipeptide showed adjuvant activity after in vitro sensitization of C57Bl/6J mouse spleen cells to the alloantigen mitomycin C-treated DBA/2 mouse spleen cells. It was also shown that 6-O-stearoylation of N-acetylmuramylpeptide could not potentiate the adjuvant activity of N-acetylmuramyldipeptide. Mitogenic and antitumor activities were not observed in either N-acetylmuramyldipeptide or 6-O-stearoyl-N-acetylmuramyldipeptide in mouse systems.

Adjuvants, Immunologic↗
PubMed1976

Mycobacterial ribonucleic acid: comparison with mycobacterial cell wall fractions for regression of murine tumor growth.

Mycobacterial ribonucleic acid (RNA) and cell wall skeleton fraction isolated from H37Ra caused P-815 mastocytoma regression in DBA/2 mice provided the animals were presensitized with freshly harvested living H37Ra cells. In the absence of presensitization, only the RNA fraction inhibited. Cell wall skeleton fraction, under these conditions, stimulated tumor growth. Cell wall lipids (from H37Ra) added to H37Ra cell wall skeleton fraction did not increase the inhibitory activity of cell wall skeleton fraction alone. Mycobacterial RNA appeared to be an effective inhibitor of P-815 mastocytoma metastases as shown by (i) the inhibition of a second footpad lesion distant from the one treated and (ii) increase in survival time.

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

Tumor cell respiration following irradiation.

Oxygen consumption rates for mouse mastocytoma cells examined from 3 to 4 hours after x-irradiation with 250-2000 rads were consistently higher than controls. Cyclic fluctuations in oxygen consumption per cell were dose-dependent; peaks in consumption were generally greater in magnitude and occurred later in time with increasing dose. The cyclic response in consumption is probably due to cell synchronization effects, while the overall higher respiration rates of irradiated cells may reflect increased metabolic activity in response to radiation damage. Oxygen consumption rates for the total cell population were cyclic after 250 and 500 rads, but declined steadily after 1000 or 2000 rads; oxygen consumption rates tended to be lower than controls, especially 12-24 hours postirradiation. Differences between cellular and population oxygen consumption rates reflect changes in cell number after irradiation. It is suggested that postirradiation reoxygenation kinetics in solid tumors may result from changes in tumor oxygen demand.

Animals↗
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.

Animals↗
PubMed1975

Studies on the mechanism of macrophage-mediated cytotoxicity.

MCF is a product of sensitized T lymphocytes, which is actively synthesized and secreted when lymphocytes are incubated with the appropriate target cells. The process of macrophage activation leading to cytotoxicity needs a period of 24h. Macrophage-mediated cytotoxicity is restricted to the specific target cell. B cell antibody does not seem to be involved. The reaction cannot be inhibited by rabbit antimouse immunoglobulin. However, various conditions, which may interfere with this specificity, are discussed.

Absorption↗
PubMed1979

Effects of the obese (ob/ob) genotype on spleen cell immune function.

Spleen cells from mice homozygous for the obese (ob) mutation killed DBA/2 mastocytoma target cells less well than spleen cells from lean littermates or unrelated age-and sex-matched controls of the same strain. Killing was impaired only when the attacker cells were primed in vivo, not following in vitro priming. Hence the effect of the ob/ob genotype is not to produce an irreversible functional change in the lymphocyte, but rather to produce an environment in which lymphocytes are less able to react to priming antigen. Not only were the spleen cells of in vivo primed obese mice less active than those of lean controls, but also their number per spleen was significantly decreased. Such a quantitive difference was no longer found in adrenalectomised animals, but the qualitative difference in spleen cell cytotoxic activity still occurred. This suggests that adrenocortical hyperfunction may affect immune function in obese mice, without necessarily being the only factor in the in vivo environment of obese mouse spleen cells capable of depressing cellular immune reactivity.

Adrenalectomy↗
PubMed1977

Comparative ultrastructural study of mast cells in mastocytoma and mastocytosis.

The ultrastructural aspects of mast cells from skin lesions in 2 patients with mastocytoma were compared to those from lesions in 4 patients with mastocytosis, 3 with cutaneous and 1 with systemic involvement. In mastocytoma, the mast cells accumulated in a large mass. They revealed short cytoplasmic villi and were similar, morphologically, to mast cells of normal skin and gingiva. In the diffuse types of the disease, cutaneous and systemic, the cells were arranged in small groups. In addition to normal mast cells, there were also irregular or bizarre-shaped cells presenting long and twisted cytoplasmic protrusions. In the case with the systemic involvement and in 2 of 3 cases with apparently cutaneous diffuse lesions, the villi of adjacent cells interlaced and showed a tendency to form mast cell aggregates. The pathognomonic value of the above observation seems worthy of further investigations.

Cell Membrane↗
PubMed1975

Properties of a subpopulation of T cells bearing histamine receptors.

C57BL/6 mice immunized i.p. with alloantigen (P815 mastocytoma cells) develop cytolytically active thymus-derived (T) splenic lymphocytes. The definition of specific histamine receptor sites on effector T cells has been studied by measuring the in vitro effects of the hormone on cytolytic activity. Histamine was found to inhibit cytolysis reversibly and to increase lymphoid cell cyclic AMP levels. Both of these histamine activities were reversed by burimamide and metiamide; neither activity was affected by diphenhydramine or pyrilamine. These findings indicate that modulation of effector T cell activity by histamine is mediated only by one of the subtypes of tissue histamine receptors, designated a histamine-type 2 receptor. This receptor appears to be present on cytolytically active cells; there is no evidence for activation by histamine of auxiliary or "suppressor" cells. The estimated dissociation constant (KB) for the burimamide-receptor complex (9 times 10-minus 6 tm) and for the metiamide-receptor complex (8 times 10-minus 7 M) indicated that the histamine receptor on T cells is quite similar to histamine-type 2 receptors in other tissues. Cells bearing such receptors could not be isolated by passage through a column of histamine-coated tsepharose beads. The cytolytic activity of spleen cells taken from mice early (days 7-9) after immunization is virtually unaffected by histamine in vitro. In contrast, the activity of spleen cells taken from mice later in the immune response is progressively more susceptible to inhibition by histamine. After reaching a maximum at day 11, the spleen cell cytolytic activity falls in a pattern that parallels the increase in susceptibility to histamine. The susceptibility of effector T cells to histamine appears also to reflect their site of origin, for peritoneal exudate effector cells were found to be significantly less sensitive than spleen cells to inhibition by histamine. The progressive increase in inhibition by histamine apparently reflects the appearance of greater numbers of specific histamine-type 2 receptors, and is probably a general phenomenon, for spleen cells from A/J or C3H mice immunized with either P815 mastocytoma (H-2d) or EL-4 (H-2b) cells showed the same effect. However, the appearance of histamine receptors could be altered by prior immunization with an unrelated alloantigen: thus, when A/J mice are preimmunized with EL-4, a subsequent immunization with mastocytoma cells results in peak spleen anti-H-2d activity at day 9 instead of days 11-13, and the appearance of significant (greater than 40 percent) inhibition by histamine as early as day 8 instead of day 16. The physiological role of the histamine receptors is as yet undefined, though their unexpected rate of appearance on effector T cells, coincident with a decline in the number of lytically active cells in vivo, may be a significant hint that hormone receptors play a role in the control of T-cell proliferation.

Animals↗