title: Suppression of in vitro antibody production by dimethylnitrosamine in mixed cultures of mouse primary hepatocytes and mouse splenocytes.
abstract: The suppression of in vitro antibody responses by dimethylnitrosamine (DMN) was produced in a mouse hepatocyte and splenocyte co-culture system. Mouse hepatocytes were isolated from female B6C3F1 mice and cultured for 20-24 hr to allow the formation of a monolayer on collagen-coated plastic petri dishes. Spleen cells were isolated from the same hybrid and were co-cultured with the hepatocytes along with DMN. Cyclophosphamide (CP), an immunosuppressive agent requiring metabolic activation that was included as an initial positive control, produced a marked suppression of the in vitro antibody responses to LPS, DNP-Ficoll, and SRBCs in 4 hr in the co-culture system. Under comparable conditions DMN markedly suppressed the response to SRBCs, marginally suppressed the response to DNP-Ficoll, and did not suppress the polyclonal response to LPS. The suppression by DMN was related to the rocking speed during the 4-hr co-culture period and was optimally produced when the cultures were not rocked. Addition of serum into the medium (10% fetal calf serum) during the co-culture period did not change the effects of DMN on the antibody response. However, the addition of extracellular DNA (1 mg calf thymus DNA/ml) prevented the suppression of the antibody response by DMN. These results suggest that DNA represents the primary macromolecular target for the reactive intermediate of DMN, and indicate that a syngeneic co-culture system can be used to characterize the in vitro immunosuppression
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D003470:Culture Media / Q000494:pharmacology; D004247:DNA / Q000494:pharmacology; D004128:Dimethylnitrosamine / Q000494:pharmacology*; D005260:Female; D007166:Immunosuppressive Agents; D066298:In Vitro Techniques; D008099:Liver / Q000276:immunology*; D051379:Mice; D009068:Movement; D013154:Spleen / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects
chemical_list: D003470:Culture Media; D007166:Immunosuppressive Agents; D004247:DNA; D004128:Dimethylnitrosamine