title: Theophylline induced non specific suppressor activity in human peripheral blood lymphocytes.
abstract: It is wellknown that theophylline yields phenotypic changes on suppressor cells. In the present study we investigated the possibility that theophylline could directly induce a suppressor activity on a lymphocyte subpopulation. We observed that a short preincubation (120 min at 37 degrees C) with theophylline (1mM) activates human peripheral blood lymphocytes to suppress mitogenic response of autologous cells. This activity was not evident on a T cell subpopulation depleted of theophylline-sensitive (T-sens) lymphocytes. Theophylline mediated suppressor activity is only present in the Concanavalin A stimulated cultures, thus suggesting a synergism between Concanavalin A and theophylline in the expression of non specific suppression. Moreover we observed that after a 24 hrs preincubation of lymphocytes in complete culture medium there was a complete loss of theophylline-induced suppression. Such a preincubation time also produced a decrease in the theophylline-mediated enhancement of intracellular 3', 5' cyclic adenosine monophosphate levels and the impairment of E-rosette formation, suggesting that theophylline acts mainly on a "short-lived" suppressor lymphocyte subset.
authors.forename: M R
authors.initials: MR
authors.lastname: Zocchi
authors.forename: R
authors.initials: R
authors.lastname: Pardi
authors.forename: G
authors.initials: G
authors.lastname: Gromo
authors.forename: E
authors.initials: E
authors.lastname: Ferrero
authors.forename: M E
authors.initials: ME
authors.lastname: Ferrero
authors.forename: C
authors.initials: C
authors.lastname: Besana
authors.forename: C
authors.initials: C
authors.lastname: Rugarli
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D000242:Cyclic AMP / Q000097:blood; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D012397:Rosette Formation; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects*; D013806:Theophylline / Q000494:pharmacology*
chemical_list: D008937:Mitomycins; D010835:Phytohemagglutinins; D003208:Concanavalin A; D016685:Mitomycin; D013806:Theophylline; D000242:Cyclic AMP