title: The immunosuppressive effects of 5-fluorocytosine and 5-fluorouracil.
abstract: 5-Fluorocytosine (5-FC) is weakly immunosuppressive when given in lethal doses to mice, and inhibits the responses of mouse and human lymphoid cells to plant lectins at concentrations of 1 mg/ml or more. 5-FC has about 1% of the immunosuppressive activity of 5-fluorouracil in vivo and 0.1% in vitro. Deamination of small amounts of 5-FC to 5-FU or conversion to other toxic metabolities may account for its immunosuppressive effects. The in vitro effects of 5-FC could also be accounted for by the presence of traces (0.1%) of 5-FU as a contaminant.
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D003596:Cytosine / Q000031:analogs & derivatives*; D005260:Female; D005437:Flucytosine / Q000494:pharmacology*; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D007166:Immunosuppressive Agents; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D051379:Mice; D010835:Phytohemagglutinins / Q000494:pharmacology; D013154:Spleen / Q000166:cytology
chemical_list: D007166:Immunosuppressive Agents; D010835:Phytohemagglutinins; D003208:Concanavalin A; D003596:Cytosine; D005437:Flucytosine; D005472:Fluorouracil