title: Permissive effect of cytochalasin B on DNA synthesis in concanavalin-A-treated lymphocytes.
abstract: Unfractionated or T-cell-enriched human lymphocytes can be stimulated to undergo DNA synthesis and mitosis by the addition of polyclonal cell activators such as the plant lectins phytohaemagglutinin and concanavalin A (ConA). Under conventional culture conditions stimulated cells cease proliferating only a few days after the first cells have initiated DNA synthesis. Cytochalasin B (CB), which is non-mitogenic per se, causes a prolongation of the period during which ConA stimulates DNA synthesis from normally 3-5 days to more than 3 weeks. The CB-induced prolongation of cell proliferation is clearly stage-specific in the sense that the CB effects are exerted after an initial period of 24 h and do not come into effect until 48 h after onset of ConA stimulation. In contrast, CB exerts a slight suppressive action on DNA synthesis between 24 h (when activated cells initiate DNA synthesis) and 48 h after onset of stimulation. These two separate effects of CB, i.e. augmentation of lymphocyte stimulation 48 h after stimulation, and suppression of stimulation before this point of time, are relatively independent of the concentration of CB.
mesh_terms: D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology*; D003571:Cytochalasin B / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
chemical_list: D003208:Concanavalin A; D003571:Cytochalasin B; D004247:DNA