dinitrobenzenes and Cell-Transformation--Neoplastic

Topics: Animals; Antibody Formation; Antigen-Antibody Complex; Antigens; Cattle; Cell Transformation, Neoplastic; Dinitrobenzenes; Disease Models, Animal; Immune Tolerance; Immunoglobulin Idiotypes; Mice; Multiple Myeloma; Rabbits; T-Lymphocytes

The effects of four isomers of dinitrotoluene (DNT) and technical DNT (a mixture of DNT isomers and other compounds, with 2,4-DNT as the major constituent) were studied in two short-term in vitro assays. None of the isomers or technical DNT induced an increase in morphological transformation of Syrian hamster embryo (SHE) cells. Four DNT metabolites (2,4-diaminotoluene, 2-amino-4-nitrotoluene, 2-amino-6-nitrotoluene, and 2,4-dinitobenzoic acid), representing different stages in reduction or oxidation of DNT isomers, were also negative for induction of morphological transformation. The DNT isomers were tested in an intercellular communication assay based on dye transfer. 2,4-DNT, 2,6-DNT, and technical DNT inhibited intercellular communication in the SHE cell line BPNi at toxic concentrations. This may be reminiscent of in vivo data showing promoting activity of these compound. 2,3-DNT and 3,4-DNT did not inhibit communication.

Topics: Animals; Cell Communication; Cell Transformation, Neoplastic; Cricetinae; Dinitrobenzenes; Embryo, Mammalian; Isomerism; Nitrobenzenes; Phenylenediamines; Time Factors

Technical grade dinitrotoluene (TDNT), composed principally of 2,4-DNT (76%) and 2,6-DNT (20%), is a potent hepatocarcinogen when fed to male F-344 rats for 1 year (100% incidence of hepatocellular carcinoma) while 2,4-DNT is only weakly hepatocarcinogenic. The present investigation was designed to determine the relative initiating potential of DNT isomers compared with the initiating potential of TDNT. A single administration of either TDNT or 2,6-dinitrotoluene (75 mg/kg, p.o.), in combination with partial hepatectomy, initiated hepatocytes in rats when assayed using hepatic initiation-promotion protocols. Five other DNT isomers (2,3; 2,4; 2,5; 3,4, and 3,5-DNT) evaluated similarly exhibited no such potential. Although 2,6-DNT was a relatively weak initiator, its activity was comparable to the initiating activity detected in TDNT. These data begin to provide an explanation for the marked differences in the hepatocarcinogenic potency of TDNT and 2,4-DNT observed in independent 2 year bioassays.

Topics: Acyltransferases; Animals; Carcinogens; Cell Transformation, Neoplastic; Dinitrobenzenes; Hepatectomy; Liver; Liver Neoplasms, Experimental; Liver Regeneration; Male; Nitrobenzenes; Rats; Rats, Inbred F344; Transglutaminases

Topics: Animals; Antibody Formation; Cell Transformation, Neoplastic; Dinitrobenzenes; Female; Gamma Rays; Immunoglobulin G; Lymphoma, Non-Hodgkin; Mice; Sarcoma, Experimental

Topics: Animals; Carrier Proteins; Cell Transformation, Neoplastic; Cells, Cultured; Dinitrobenzenes; Epitopes; Ficoll; Immunoglobulin A; Male; Mice; Mice, Inbred BALB C; Myeloma Proteins; Plasmacytoma; Rabbits; Receptors, Antigen, B-Cell; T-Lymphocytes; Time Factors; Trinitrobenzenes

Tissue culture-adapted MOPC 315 mouse plasmacytoma cells which secrete monoclonal anti-DNP IgA antibody, were cultured with a variety of DNP-carrier conjugates and the production of IgA measured by pulse labeling with [3H]leucine and by plaque-forming cell assays. DNP-coupled bovine, human and rabbit gamma-globulins (containing 9 to 12 DNP groups per 50 000 mol wt of carrier) inhibited the synthesis and secretion of IgA by 40 to 80%. This inhibition was specific, since unconjugated globulins were ineffective, non-IgA proteins and DNA synthesis remained unaffected, and DNP-globulins had no effect on X5563 cells which do not bind DNP. The degree of suppression of antibody production dependen on the concentration and epitone density of the antigen and on the duration of exposure of cells to it, and was no attributable to absorption of secreted antibody by cell-bound antigen. Comparably substituted DNP conjugates of F(ab')2 and intact globulins were equally inhibitory. The inhibition of antibody synthesis by DNP-BGG was reversible following removal of the antigen. This phenomenon is similar in many respects to the antigen-induced blockade of normal antibody-secreting cells, and provides a valuable model system for analyzing the mechanisms of antigen-mediated cellular inactivation.

Topics: Animals; Antibody Formation; Antigens; Binding Sites; Carrier Proteins; Cattle; Cell Transformation, Neoplastic; Dinitrobenzenes; gamma-Globulins; Hemolytic Plaque Technique; Immunoglobulin A; Immunoglobulin Fab Fragments; Immunoglobulin G; Mice; Plasmacytoma; Rosette Formation

Dinitrophenyl-bovine albumin was coupled at room temperature to sheep red blood cells in a procedure which minimized spontaneous lysis and allowed the preparation of large batches and their use for at least 3 weeks. The modified erythrocytes were used as a substrate for detecting local hemolytic plaques in agar by myeloma MOPC 315 cells, which secrete a paraprotein IgA with high affinity for dinitrophenyl ligand. Conditions maximizing the number of plaques formed by a given number of tumor cells were found to include coupling the erythrocytes at 1 mg/ml dinitrophenyl-bovine albumin with a molar ratio of about 50, and incubation with an amino-to-carboxy cross-linking agent, 1-ethyl-3(3 dimethyl aminopropyl) carbodiimide, at 2 mg/ml for 50 min. The method thus developed was employed to measure cellular and antibody-dependent immune reactions against the MOPC 315 cells. The experimental results show comparisons of the plaque technique with other measurements of tumor cell injury. The nature of the assay, which requires only 500 cells per plating, and which tests the synthetic capacity of single cells, suggests its use in experiments which limit the number of target cells, and in immune reactions causing injury, but not necessarily lysis, of the target cells.

Topics: Animals; Antibodies, Neoplasm; Cattle; Cell Transformation, Neoplastic; Cells, Cultured; Dinitrobenzenes; Erythrocytes; Ethyldimethylaminopropyl Carbodiimide; Hemolytic Plaque Technique; Immunity; Immunity, Cellular; Mice; Mice, Inbred BALB C; Neoplasms, Experimental; Serum Albumin, Bovine; Sheep