Detection of relevant farmer's lung antigens by using immunoblots of two-dimensional electrophoresis.

Crude antigenic extract from Faenia rectivirgula (Micropolyspora faeni), the most commonly implicated organism in farmer's lung disease, was subjected to two-dimensional electrophoresis. The antigenic components resolved by this method were electrophoretically transferred to nitrocellulose sheets. These bound antigens were allowed to react with sera from farmer's lung patients and individuals exposed to farming environments. The antigen-antibody reaction was visualized by a sandwich method employing a biotin-avidin system and peroxidase staining. Patients' sera demonstrated eight to 29 spots on the nitrocellulose sheets while exposed individuals showed fewer spots (zero to 11 reactive spots). Although immunoblot results showed considerable variation between patients, this method also provided additional immunochemical information about the various antigenic components reacting with the specific antibodies. Two major antigenic clusters were found to react with all the patient sera, while asymptomatic exposed individuals showed only occasional reactivity with these antigenic components. Demonstration of these antigenic components might be of value in determining the quality of the antigen preparations for reliable immunological evaluation of patients. In addition, such immunochemical information might be utilized in the selective purification of reliable antigens and in their standardization.