Stability studies of Calvatia cyathiformis basidiospore allergens

Calvatia cyathiformis allergens in unfractionated extract (crude), and in extract sequentially fractionated by gel filtration (GF) and hydrophobic interaction chromatography (HIC) were tested for stability. C. cyathiformis allergen sources (crude, GF, HIC) were sampled immediately (0 h), or incubated at 4, 24 or 37 degrees C and then sampled at 8, 24 or 96 h. Polyacrylamide gel-isoelectric focusing immunoprints revealed 3 allergen(s) groups, or bands (Bds) with respective pI of 3.6-4.6, 6.6 and 9.3. Only Bds 3.6-4.6 were stable at 37 degrees C. At 24 degrees C, Bds 3.6-4.6 persisted to 96 h, Bd 6.6 persisted 24 h, and Bd 9.3 waned in 8 h. At 4 degrees C all 3 allergens in HIC were stable for 8 and 24 h; Bd 9.3 was reduced at 96 h. All allergen activity was labile to low pH conditions except for Bds 3.6-4.6. Proteinase K degraded Bd 9.3 more rapidly than Bd 6.6. Immunoprint patterns corresponded to the stained gels and were consistent among different sources. Bd 9.3 is very labile, but reactive with 63% of sera tested. Since 10-15% of C. cyathiformis reactors bind IgE only to Bd 9.3, this is notable variability, and significant for diagnosis and treatment.