Abstract
With regard to the pathogenesis of hypersensitivity pneumonitis, cells in lung lavage fluid were studied in rabbits with respect to their functions.
Granulomatous lesions in the lung were produced with transtracheal insufflation of Micropolyspora faeni antigen in rabbits previously sensitized with subcutaneous injection of M. faeni emulsified in complete Freund's adjuvant (group I) and compared with groups of rabbits treated with transtracheal injections of the antigen after subcutaneous sensitization with incomplete Freund's adjuvant (group II) or rabbits treated only with systemic sensitization with M. faeni emulsified in complete Freund's adjuvant (group III).
Total lavaged cells increased in number in group I with mild increase of lymphocytes. The phagocytic rate of lung macrophages studied with Candida yeast phagocytosis was greater in group I (p<0.05). However, the positive response to LPS-activated sera, that was shown in control animals, was diminished or decreased in all animals of group I and some of group II. Migration of cells in lavage fluid was inhibited in the presence of M. faeni antigen most markedly in group I. However, migrating lung macrophages from group I rabbits were found to have aggregated even without antigen.
These changes of the lung macrophages from granulomatous lesions were discussed with relationship to the pathogenesis of the lesions most directly related to type III allergy of Coombs and Gell.
