DIFFERENTIAL CELLULAR IMMUNE RESPONSE IN BAL AFTER INHALATION OF PIGEON SERUM AND ASPERGILLUS EXTRACT IN ACUTE AND CHRONIC MURINE MODELS OF HYPERSENSITIVITY PNEUMONITIS

Introduction Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by inhalation of, mainly, avian and fungal antigens. However, the immunological mechanisms involved are not yet well understood. The objective of the study was to compare the cellular immune response after exposure to pigeon serum and Aspergillus sp. extract in acute and chronic murine models of hypersensitivity pneumonitis (HP). Methods The animal models were conducted using C57BL/6J strain mice. The HP groups were sensitized with two injections (48 hours apart) of 100 µL of pigeon serum (200 µg/ml) for the avian-origin HP group (HPA) and Aspergillus extract (200 µg/ml) for the fungal-origin HP group (HPF). The control group was sensitized with saline serum. Antigen exposure was performed via intranasal instillations of 40 µL on three consecutive days per week for three weeks in acute model and sixteen weeks in chronic model. Leukocyte patterns were evaluated in bronchoalveolar lavage (BAL). Results Both acute HP groups showed a higher number of total cells (p=0.0015 and p=0.0059), neutrophils (p=0.0002 and p