Micropolyspora faeni and farmer's lung disease

Several methods were used to obtain serologically active materials from cultures of Micropolyspora faeni. From the results of immunodiffusion and immunoelectrophoresis tests on these materials it is suggested that preparations for the laboratory diagnosis of farmer's lung disease (FLD) should contain concentrated culture supernatant (CS) and extracts of mycelium obtained by ultrasonic treatment (MU). Although CS and MU have many serological activities in common they also possess activities unique to each.Extraction of mycelium with trichloracetic acid, boiling water or methanol yielded a product which gave simple patterns in immunodiffusion tests. The products contained little protein but were rich in carbohydrates, particularly arabinose, galactose and glucosamine. A similar material was obtained from a cell-wall preparation by treatment with lysozyme. Antibodies to the serologically active substances in these materials occurred more frequently in sera of patients with FLD than antibodies to any other M. faeni antigen.Attempts to obtain serologically active materials from spores were unsuccessful. Moreover antibodies to M. faeni could not be removed from patients' sera by absorption with partially purified spore preparations. It is suggested that the hypersensitivity in FLD arises from exposure to mycelial antigens.