T Lymphocytes and Eosinophils in Allergen-induced Late-phase Asthmatic Reactions in the Guinea Pig

Publisher Website
Google Scholar
Abstract
The kinetics and phenotype of T lymphocytes infiltrating the airways of guinea pigs undergoing late-phase asthmatic reactions (LAR) were studied with monoclonal antibodies, cytofluorimetry, and immunocytochemistry. Challenge of sensitized animals with aerosolized ovalbumin was followed by early (2 h) and late-phase (17 h) bronchoconstriction. The induction of hypersensitivity, by aerosolized antigen, was associated with an increase in mucosal T cell numbers, which consisted almost entirely of CD8+ T cells. Following allergen challenge of fully sensitized animals, a biphasic rise in total T cell (CD3+) numbers was observed in the bronchial mucosa, peaking at 17 and 48 h. A similar pattern of T cell accumulation was observed in the bronchial adventitia but with an extra early peak at 2 h. In contrast to the T cell influx of the sensitization phase, the postchallenge infiltrate consisted largely of CD3 + ,CD8− cells. Eosinophil numbers were elevated in both submucosa and adventitia, with a single broad peak between 17 and 48 h. T cell infiltration was compared with eosinophil accumulation: while correlations between T cell and eosinophil numbers varied over the 96 h of the experiment, strong associations were observed between CD8+ numbers and eosinophils in the adventitia at 6 h (r = 0.733, p < 0.01) and between CD3+ numbers and eosinophils in the submucosa at 72 h (r = 0.88, p < 0.001). No significant changes were detected in T cell or eosinophil numbers in the lung parenchyma. There was a postchallenge increase in eosinophils (but not T cells) in bronchoalveolar lavage (BAL). In contrast, analysis of blood leukocytes showed no changes in T cell total or subset numbers during the progression of the LAR. These results indicate that accumulation of T cells in the airways is a feature of the LAR in this model. These observations are consistent with human BAL and skin studies of the allergen-induced late-phase reaction. These data also illustrate that evaluation of distant compartments (blood and BAL) may not fully reflect rapidly evolving tissue infiltration in the bronchial mucosa.

This publication has 16 references indexed in Scilit: