Isolation and characterization of two allergens from Dermatophagoides farinae

Two purified allergens, designated as DF1 and DF2, were isolated from the extract of the whole culture of Dermatophagoides farinae by a combination of ammonium sulfate precipitation and ion exchange, hydrophobic, chelate and gel chromatography. DF1 was isolated as a heat-sensitive acidic protein with an apparent molecular weight of 25,000 and an isoelectric point of 4.6-7.2. DF2 was isolated as a heat-stable basic protein with an apparent molecular weight of 15,000 and an isoelectric point of 7.8-8.3. No allergenic cross-reactivity was seen between DF1 and DF2. Both DF1 and DF2 were shown to be the major allergens of D. farinae by the results of radioallergosorbent test and histamine release assay.