Comparison by electroblotting of IgE-binding components in extracts of house dust mite bodies and spent mite culture

Abstract

Eight Dermatophagoides pteronyssinus extracts (three culture extracts, four mite body extracts, and the World Health Organization International Standard [IS]) were investigated by side-by-side sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by electrotransfer to nitrocellulose, and by probing with a pooled serum from mite-allergic subjects. Representative body and mite culture extracts were compared by probing with individual sera, and both types of extract were also compared by RAST-inhibition studies. Extracts from the same source differed in the molecular weight (MW) of some of their IgE-binding components. In general, most IgE-binding components in culture extracts and the IS were in the 14 to 35 kd MW region, whereas extracts from mite bodies and one culture extract contained more IgE-binding components of higher MW (35 to 110 kd). Comparison of representative mite body and culture extracts by use of 22 separate sera resolved 26 and 19 IgE-binding components in the two extracts, respectively. Patterns of RAST inhibition produced by both types of extracts when they were used either as the inhibitor or as the allergosorbent demonstrated qualitative differences between the two types of extracts. These results demonstrate that mite extracts may differ considerably in their allergenic composition and emphasize the need for standardization of mite allergenic extracts and the reexamination of the suitability of the D. pteronyssinus IS.