Identification and characterization of important cockroach allergens

Allergens extracted from American and German cockroach species have been identified as significant sensitizing agents in the induction/exacerbation of asthma. In the present study, gel-filtration fractions of saline extracts of American cockroach (Periplaneta americana) whole bodies (AWBE fraction 2) and German cockroach (Blattella germanica) whole bodies (GWBE fraction 2) were used to identify and characterize important cockroach allergens by immunoprinting. In addition, allergens from AWBE and GWBE fractions 2 were additionally fractionated by chromatofocusing on polybuffer exchanger. Immunoprinting studies demonstrated several important acidic allergens in cockroach whole body extracts. All but one allergen had an acid isoelectric point (pH 2.80 to 5.20). Two allergens, one that focused at pH 3.50 and another allergen (or group of isoallergens) that focused between pH 4.15 to 4.55 were reactive with most sera obtained from cockroach-sensitive subjects. Chromatofocusing and subsequent skin test and RAST studies of AWBE and GWBE confirmed the presence of significant cockroach allergens with isoelectric points within the zone of pH 3.75 to 4.50. RAST-inhibition studies demonstrated the similarity of these allergens between AWBE and GWBE. Collectively, these observations identify the presence of several acidic cockroach allergens presumably shared between AWBE and GWBE.