Abstract
Some allergic asthma individuals did not display airway obstruction after an anaphylactic challenge (dAOAC); however, the mechanism involved in this process is unknown, it has been suggested that regulatory T cells (Tregs) may be involved. We developed a model of airway obstruction-induced by antigenic challenge in guinea pig (GP) to elucidate the potential role of Tregs. In our model, the sensitized GP are intermittently challenged with the antigen (ovalbumin, OA; applied every 10 days). We found two groups of GP ones that showed dAOAC and ones that did not. Then, we evaluated the antigen-induced airway obstruction and hyperresponsiveness (HR) to histamine and identified the population of Tregs in the bronchoalveolar lavage (BAL) in GP after three and six OA challenges. Controls received saline solution instead of OA. From the first challenge, GP that dAOAC showed a transient response and developed of HR at third and sixth challenges. In GP that did not dAOAC HR was observed at third but not at sixth challenge. The total number of cells that produced TGF-β1 and IL-10 in BAL were similar to controls in all groups. In GP that dAOAC, CD4+CD25+Foxp3+ T cells (nTreg) numbers were reduced in BAL in comparison to controls and GP that did not dAOAC. The number of inducible regulatory T cells (iTreg) that produced IL-10 was similar to controls in all groups, while iTregs that produced TGF-β1 increased only in the group of GP that did not dAOAC on the sixth challenge. We suggests that nTregs might play an important role in suppression of dAOAC and that probably iTregs that produce TGF-β1 are involved in the attenuation of HR in this asthma model.
- © 2011 ERS