Studies on Alternaria allergens. III. Isolation of a mafor allergenic fraction (ALT-I).

The allergens present in crude Alternaria alternata extract were fractionated by sequential ammonium sulfate precipitation, DEAE cellulose ion-exchange chromatography, preparative flat-bed electrofocusing, and Sephadex G-100 gel filtration. The carbohydrate-rich fraction isolated (Alt-I) was heterogeneous by polyacrylamide gel disc electrophoresis and by thin-layer electrofocusing. By preparative polyacrylamide gel electrophoresis the Alt-I fraction could be further separated into at least five subfractions, all of which contained similar allergenic activity. Significant elevations in IgE antibody to Alt-I were found in 21