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  • Title: Allergen challenge primes for IL-5 mRNA production and abrogates beta-adrenergic function in peripheral blood T lymphocytes from asthmatics.
    Author: Borger P, Jonker GJ, Vellenga E, Postma DS, De Monchy JG, Kauffman HF.
    Journal: Clin Exp Allergy; 1999 Jul; 29(7):933-40. PubMed ID: 10383594.
    Abstract:
    BACKGROUND: In previous studies, we have found a dysfunctional adenylyl cyclase (AC) system in patients with asthma after allergen provocation, which resulted in a 40-50% decreased generation of intracellular cAMP. In addition, in activated T helper lymphocyte clones, it has been demonstrated that IFN-gamma (TH1-like cytokine) and IL-5 (TH2-like cytokine) are differentially regulated by the AC system. Therefore, we postulate that an increased IL-5/IFN-gamma ratio as observed in asthmatics might be due to a dysfunctional AC system. OBJECTIVE: To assess whether a dysfunctional AC system as observed in asthmatics after allergen provocation, is responsible for an increased IL-5/IFN-gamma cytokine ratio. METHODS: Peripheral blood T lymphocytes of seven asthma patients were stimulated with anti-CD3 plus anti-CD28 MoAbs in the absence and presence of isoproterenol (ISO) and prostaglandin E2 (PGE2) to activate the AC system. Before, 3 h and 24 h after allergen provocation, IFN-gamma and IL-5 mRNAs were detected by semiquantitative RT-PCR. RESULTS: Before allergen provocation, ISO (10-5 mol/L) significantly downregulated IFN-gamma mRNA (P < 0.03, n = 6), and showed a trend to upregulate IL-5 mRNA (P = 0.138, n = 5). Three and 24 h after allergen provocation, ISO was not longer able to modulate IFN-gamma and IL-5. In contrast with the observations with ISO, PGE2 still dose-dependently inhibited IFN-gamma mRNA, both before, 3 h and 24 h after allergen provocation (n = 7). IL-5 mRNA, but not IFN-gamma mRNA, was significantly upregulated in anti-CD3 plus anti-CD28-activated T cells (P < 0.05, n = 5) 24 h after allergen provocation, compared with before allergen provocation. CONCLUSION: Twenty-four hours after allergen provocation, a significant reduction of beta-adrenergic control on IFN-gamma and IL-5 mRNA expression was observed in peripheral blood T lymphocytes, which coincides with a selective priming of IL-5 mRNA production.
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