Isolation of spore specific allergens from Alternaria

Extracts of Alternaria alternata spores and mycelia were prepared. Crossed immunoelectrophoresis showed the presence of at least 40 antigens in these extracts. Analysis of seven commercial extracts by CIEP and isoelectric focusing showed many fewer components and a high degree of variability. Eight of the antigens in the spore extract demonstrable by CIEP were not present in mycelia extracts. This spore-specific fraction was isolated by solid phase immunoadsorption and shown to be potent antigenically and allergenically. The extracts of mycelia, spore and spore-specific fraction demonstrated strong reactivity with 92 Alternaria sensitive patients by both RAST and skin test. About half of the patients were significantly more reactive to spore and/or spore-specific than the mycelia. Many of the spore antigens are either common to or cross-reactive between spore and mycelia but there are a minimum of eight spore-specific antigens, at least one of which is a strong allergen.