Shifts in lung lymphocyte profiles correlate with the sequential development of acute allergic and chronic tolerant stages in a murine asthma model

T lymphocytes have a central regulatory role in the pathogenesis of asthma. We delineated the participation of lymphocytes in the acute allergic and c hronic tolerant stages of a murine model of asthma by characterizing the va rious subsets of lymphocytes in bronchoalveolar lavage and lung tissue asso ciated with these responses. Acute (10-day) aerosol challenge of immunized C57BL/6J mice with ovalbumin resulted in airway eosinophilia, histological evidence of peribronchial and perivascular airway inflammation, clusters of B cells and TCR gamma delta cells in lung tissue, increased serum IgE leve ls, and airway hyperresponsiveness to methacholine. In mice subjected to ch ronic (6-week) aerosol challenge with ovalbumin, airway inflammation and se rum IgE levels were significantly attenuated and airway hyperresponsiveness was absent. The marked increases in lung B and T cell populations seen in the acute stage were also significantly reduced in the chronic stage of thi s model Thus, acute ovalbumin challenge resulted in airway sensitization ch aracteristic of asthma, whereas chronic ovalbumin challenge elicited a supp ressed or tolerant state. The transition from antigenic sensitization to to lerance was accompanied by shifts in lymphocyte profiles in the lung and br onchoalveolar lavage fluid.