Occupational allergy in an entomological research centre. II. Identification of IgE-binding proteins from developmental stages of the blowfly Lucilia cuprina and other species of adult flies.

Sera from 30 workers in an entomological research institute and from five Sydney asthmatics, all with serum IgE antibodies to sheep blowfly (Lucilia cuprina) antigens, were studied with the aim of identifying individual IgE-binding proteins in extracts of L. cuprina adult flies, larvae and eggs, and in extracts of related species of flies from the order Diptera. Using protein blotting, 21, 18 and nine different IgE-binding components were identified in extracts of L. cuprina adult flies, larvae and eggs, respectively. A component(s) of MW 67 kD found in all three developmental stages, showed the highest frequency of IgE-binding; reacting, for example, with 70% of the sera tested with the adult fly extract. Some components were detected in only one of the three developmental stages. Investigations of possible allergenic cross-reactivity between L. cuprina and extracts from six other related species of flies revealed IgE-binding bands in each of the extracts as well as in an extract of Agrotis infusa, a cutworm not belonging to the order Diptera. One strongly reacting component of MW 20 kD was detected in extracts of five different fly species as well as in the A. infusa extract. The results suggested that allergenic cross-reactivity between some fly species exists, and may extend to taxonomically unrelated insect species.