Effects of isoproterenol on IL-2 and cAMP production in peripheral T cells from asthmatic and non-asthmatic subjects sensitive to Candida.
Immunity to Candida albicans (Candida) is characterized by a Th-1 type pattern of reactivity. Candida is rarely a cause antigen for bronchial asthma. Beta agonists have been found to inhibit secretion of IL-2 from T cells through intracellular cAMP elevation. We examined effects of isoproterenol (ISO) on Candida-stimulated T cells. Peripheral T cells obtained from six Candida-sensitive asthmatics, six Candida-sensitive non-asthmatic subjects, and six normal donors by Ficoll-Hypaque gradient centrifugation and nylon-wool column chromatography were incubated with Candida antigen or concanavalin A (Con A) in the absence or presence of ISO. Secretion of IL-2 and intracellular accumulation of cAMP were assayed by ELISA. Con A induced secretion of IL-2 in each of the three groups. Candida antigen induced IL-2 secretion in the normal and the non-asthmatic subjects, but not in the asthmatics. ISO, which reduced Con A-induced secretion of IL-2 in a dose-dependent manner, had no effect on Candida-induced secretion of IL-2. Although ISO increased the intracellular concentration of cAMP in untreated and Con A-treated T cells from all donors, cells from the normal and the non-asthmatic subjects, but not from the asthmatics, that were co-incubated with ISO and Candida had lower levels of cAMP than those treated with ISO alone. It is suggested that Candida antigen induces secretion of IL-2 and reduces ISO-inducible accumulation of cAMP in Candida-responsive IL-2 secreting cells, which may make Candida-induced secretion of IL-2 insensitive to ISO.
Aihara
M
M
First Department of Internal Medicine, Gunma University Faculty of Medicine, Japan.
Dobashi
K
K
Horie
T
T
Iizuka
K
K
Nakazawa
T
T
Mori
M
M
D001249:Asthma / Q000276:immunology* / Q000378:metabolism*; D002175:Candida / Q000276:immunology* / Q000378:metabolism; D016022:Case-Control Studies; D003208:Concanavalin A / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006967:Hypersensitivity; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis*; D007545:Isoproterenol / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016176:T-Lymphocyte Subsets / Q000378:metabolism*
D007376:Interleukin-2; D012333:RNA, Messenger; D003208:Concanavalin A; D000242:Cyclic AMP; D007545:Isoproterenol