Comparative analysis of bovine extracts by immunoblotting and ELISA inhibition: rabbit and human responses against cow epithelial and urine antigens

Bovine epithelial and urine antigen extracts were compared using enzyme-linked immunosorbent (ELISA) inhibition assay and sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with immunoblotting. According to ELISA inhibition results, the two extracts share about 2% of their antigenic components. Urine-derived antigens seem to be antigenically closer to serum proteins than epithelial antigens, as determined by rabbit immune sera. The IgG responses of allergic farmers against epithelial antigens were directed mainly against a protein of 20 kD, while non-allergic farmers had only very weak reactions. Generally, the IgG response against urinary antigens seemed to be more heterogeneous than against epithelial antigens. Almost all cow-allergic farmers reacted with a band at 20 kD in IgE immunoblotting against urinary and epithelial antigen while all non-allergic farmers showed negative results.