cytochalasin-b and Mast-Cell-Sarcoma

Topics: Adsorption; Animals; Antigen-Antibody Reactions; Cytochalasin B; Cytotoxicity Tests, Immunologic; Immunosuppression Therapy; Leukemia, Experimental; Lymphocytes; Mast-Cell Sarcoma; Mathematics; Mice; Rats; Sarcoma, Yoshida; T-Lymphocytes; Temperature; Time Factors; Transplantation Immunology

Antigens in extracellular fluids can be processed and presented with major histocompatibility complex (MHC) class I molecules by a subset of antigen presenting cells (APCs). Chicken egg ovalbumin (Ova) linked to beads was presented with MHC class I molecules by these cells up to 10(4)-fold more efficiently than soluble Ova. This enhanced presentation was observed with covalently or noncovalently linked Ova and with beads of different compositions. A key parameter in the activity of these conjugates was the size of the beads. The APC that is responsible for this form of presentation is a macrophage. These cells internalize the antigen constructs through phagocytosis, since cytochalasin B inhibited presentation. Processing of the antigen and association with MHC class I molecules appears to occur intracellularly as presentation was observed under conditions where there was no detectable release of peptides into the extracellular fluids. When injected in vivo in C57BL/6 mice, Ova-beads, but not soluble Ova, primed CD4- CD8+ cytotoxic T lymphocytes (CTLs). Similar results were obtained in BALB/c mice immunized with beta-galactosidase-beads. The implications of these findings for development of nonliving vaccines that stimulate CTL immunity are discussed.

Topics: Animals; Antigen-Presenting Cells; Azides; Cell Line; Cytochalasin B; Deoxyglucose; Female; Histocompatibility Antigens Class I; Kinetics; Lymphoma, T-Cell; Macrophages; Mast-Cell Sarcoma; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Ovalbumin; Phagocytosis; Spleen; T-Lymphocytes, Cytotoxic; Tumor Cells, Cultured

The cytochalasins are fungal metabolites that have previously been shown to have some chemotherapeutic potential. When various cell types are treated in vitro with both cytochalasin B and vincristine, the resultant DNA fragmentation is greater than the sum of that caused by each agent alone. The levels necessary to achieve this potentiation are obtainable in vivo. DNA fragmentation induced by cytochalasin E, an actin-specific agent, is potentiated by vincristine. Pretreatment of the mastocytoma line P815 with vincristine results in an enhancement of the ability of cytochalasin B to fragment DNA. These results indicate that cytochalasin B might be effective as a chemotherapeutic agent in the presence of vincristine.

Topics: Cytochalasin B; DNA Damage; DNA, Neoplasm; Drug Synergism; Humans; Lymphoma, B-Cell; Lymphoma, T-Cell; Mast-Cell Sarcoma; Vincristine

Cytochalasin B (CB), administered i.p. to C57B1/6 mice in a single dose as a suspension in carboxymethylcellulose 2%/Tween 20 1%, inhibits in a dose-dependent and time-dependent manner the ability of spleen cells to respond to allogeneic P815 mastocytoma tumor cells in vitro. Spleen cells from CB-treated animals sensitized to X-irradiated P815 cells in 4-day cultures at a 50:1 responder:stimulator ratio and tested for specific cytotoxicity against 51Cr-labelled P815 target cells showed strong inhibition 3 h after CB treatment at a dose of 50 mg/kg. A dose of 25 mg/kg showed measureable but not statistically significant inhibition at 3 h, whereas 10 mg/kg produced only slight inhibition, and 5 mg/kg and 2 mg/kg were noninhibitory. None of the doses produced significant suppression 19 h or 72 h after CB treatment. Addition to the sensitization cultures of human recombinant interleukin-2 (rhIL-2) at 350 BRMP units/ml completely restored tumor lytic capacity. C57B1/1 mice treated with CB 50 mg/kg, i.p. and challenged i.p. with 3 x 10(7) allogeneic P815 mastocytoma cells showed a brief, time-dependent, statistically significant abrogation of allogeneic responsiveness consistent with transient reversible immunosuppression within 3-12 h following CB treatment. No such inhibition of host allogeneic responsiveness in vivo was observed when CB was administered 24 h prior to, simultaneously with, or 1, 2, or 4 days after tumor challenge. Thus CB at the highest tolerated i.p. dose in vivo causes only a transient inhibition of anti-allo-responsiveness measured in culture, and rhIL-2 used in vitro restores lytic capacity. The anti-allo effect of CB is also seen to be transient directly in vivo since allogeneic tumor outgrowth is permitted for only a brief period following administration of CB. These results indicate that the use of CB in vivo in anti-tumor chemotherapy protocols will not be complicated by profound or prolonged immunosuppressive effects.

Topics: Animals; Cytochalasin B; Cytotoxicity, Immunologic; Dose-Response Relationship, Drug; Female; Immunosuppression Therapy; Interleukin-2; Mast-Cell Sarcoma; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Neoplasm Transplantation; Organ Size; Recombinant Proteins; Spleen; Time Factors; Transplantation, Homologous

Mastocytoma P815 cells are induced to form and shed membrane vesicles (MV) from their surfaces by incubation at low temperature (4 degrees C) for 1 hr. and subsequently allowing them to warm up to room temperature (22 degrees C). Within 1-2 hrs. at room temperature, up to 90% of the P815 cells form and shed MV from their surfaces. Both cells and vesicles remain trypan blue-excluding during the MV shedding process. This process is energy dependent in that it can be inhibited by 2-deoxyglucose, sodium azide and 2-4-dinitrophenol. The shed MV can be harvested by centrifugation on a 6% Ficoll cushion and quantitated in terms of protein content. The shedding of membrane vesicles from the tumor cell surfaces results in a significant reduction in the cell size.

Topics: Animals; Antigens, Neoplasm; Antigens, Surface; Azides; Cell Count; Cell Line; Cytochalasin B; Deoxyglucose; Mast-Cell Sarcoma; Mice; Mice, Inbred DBA; Vinblastine

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.

Topics: Animals; Antigen-Antibody Reactions; Cell Line; Cytarabine; Cytochalasin B; Cytotoxicity Tests, Immunologic; Dactinomycin; Dimethyl Sulfoxide; Edetic Acid; Erythrocytes; Humans; Immune Adherence Reaction; Immune Sera; Immunity, Cellular; Leukocytes; Lymphocyte Culture Test, Mixed; Mast-Cell Sarcoma; Phagocytosis; Rabbits; Vincristine

Topics: Animals; Cell Line; Cytochalasin B; Histamine; Histamine H1 Antagonists; Histamine Release; Mast Cells; Mast-Cell Sarcoma; Mice; Mice, Inbred Strains; Neoplasms, Experimental; Serotonin

Topics: Animals; Antigen-Antibody Reactions; Cell Membrane Permeability; Chromium Radioisotopes; Cytochalasin B; Cytotoxicity Tests, Immunologic; Dextrans; Dose-Response Relationship, Drug; Mast-Cell Sarcoma; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Molecular Weight; Motion Pictures; Radioisotopes; Rubidium; Sarcoma, Experimental; Spleen; T-Lymphocytes

Topics: Animals; Colchicine; Cyclic AMP; Cycloheximide; Cytochalasin B; Edetic Acid; Emetine; Immunity, Cellular; Immunization; Mast-Cell Sarcoma; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Neoplasms; Neoplasms, Experimental; Spleen; T-Lymphocytes

Topics: Adsorption; Animals; Antigen-Antibody Reactions; Antigens; Chromium Isotopes; Colchicine; Cytochalasin B; Cytotoxicity Tests, Immunologic; Indoles; Mast-Cell Sarcoma; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mitosporic Fungi; Prostaglandins; Spleen; T-Lymphocytes; Time Factors

Topics: Animals; Antigen-Antibody Reactions; Calcium; Chromium Isotopes; Cytochalasin B; Edetic Acid; Magnesium; Mast-Cell Sarcoma; Mice; Mice, Inbred C57BL; Prostaglandins; T-Lymphocytes

Topics: Animals; Antigen-Antibody Reactions; Ascitic Fluid; Chromium Isotopes; Colchicine; Cytochalasin B; Mast-Cell Sarcoma; Mice; Mice, Inbred C57BL; Microtubules; Organoids; Spleen; T-Lymphocytes