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Antibody responses in patients with farmer's lung disease to antigens from Micropolyspora faeni
Abstract:
Three purified cell-wall glycoprotein antigens, a, b and c, sensitive to sodium periodate and resistant to pronase, were extracted from mycelium of Micropolyspora faeni with aqueous phenol or trichloracetic acid. Pronase-sensitive, sodium periodate-resistant protein antigens were extracted from mycelium with aqueous phenol. Immunoelectrophoresis was a critical method of assessing purity of preparation.Antibodies to glycoprotein antigens only occurred in clinically defined cases of farmer's lung disease, whereas antibodies to protein antigens also occurred in symptomless farmers. Precipitins to a occurred in all cases of farmer's lung disease, and this antigen was isolated and purified.Fractionation of pooled sera from cases of farmer's lung disease showed that precipitins were IgG globulins, whereas latex-agglutinating antibodies were IgG, IgA and especially IgM globulins. It is suggested that farmer's lung may involve a cytotoxic type II reaction, in which glycoproteins adsorbed to tissue cells react with IgG, IgA and IgM immunoglobulins in the presence of complement, causing cellular damage.
Insights
Farmer's lung disease involves immune responses to Micropolyspora faeni antigens. Glycoprotein antigens trigger antibodies only in patients, suggesting a specific diagnostic marker for farmer's lung.
Area of Science:
- Immunology
- Microbiology
- Pulmonary Medicine
Background:
- Farmer's lung disease is a hypersensitivity pneumonitis.
- It is caused by exposure to thermophilic actinomycetes, such as Micropolyspora faeni.
- Identifying specific antigens and immune responses is crucial for diagnosis and understanding pathogenesis.
Purpose of the Study:
- To isolate and characterize antigens from Micropolyspora faeni.
- To investigate the antibody responses to these antigens in farmer's lung disease patients and healthy farmers.
- To elucidate the immunological mechanisms involved in farmer's lung disease.
Main Methods:
- Extraction of glycoprotein and protein antigens from Micropolyspora faeni mycelium using phenol or trichloroacetic acid.
- Purification and characterization of antigens using immunoelectrophoresis.
- Analysis of patient and farmer sera for antibodies using precipitins and latex agglutination tests.
- Fractionation of immunoglobulins (IgG, IgA, IgM).
Main Results:
- Three purified glycoprotein antigens (a, b, c) and protein antigens were extracted.
- Antibodies to glycoprotein antigens were specific to farmer's lung disease patients.
- Antibodies to protein antigens were found in both patients and asymptomatic farmers.
- Precipitins to antigen 'a' were present in all farmer's lung disease cases.
- Precipitins were primarily IgG, while latex-agglutinating antibodies included IgG, IgA, and IgM.
Conclusions:
- Glycoprotein antigen 'a' is a potential diagnostic marker for farmer's lung disease.
- Farmer's lung disease may involve a cytotoxic type II hypersensitivity reaction.
- The reaction involves glycoproteins on cell surfaces interacting with patient immunoglobulins and complement, leading to tissue damage.