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Molecular cloning of Per a 1 and definition of the cross-reactive Group 1 cockroach allergens

1999; Elsevier BV; Volume: 103; Issue: 5 Linguagem: Inglês

10.1016/s0091-6749(99)70430-6

1097-6825

Erik Melén, Anna Pomés, Lisa D. Vailes, L. Karla Arruda, Martin D. Chapman,

Food Allergy and Anaphylaxis Research

Background: Sensitization to allergens produced by German and American cockroaches is strongly associated with the cause of asthma. Most of the cockroach allergens identified to date have been species specific. Objective: The aim of this study was to identify and sequence cross-reactive cockroach allergens. Methods: A Periplaneta americana cDNA library was screened with IgE antibody from patients in the United States who were allergic to cockroach and who were sensitized to Blattella germanica . Results: A cDNA clone was isolated that contained an 870-bp sequence with a 695-bp open reading frame, encoding a 231 amino acid protein, molecular weight 26.2 kd. Plaque immunoassays using anti-Bla g 1 and anti-Per a 1 mAbs and a panel of human IgE antibodies showed that the protein expressed by these clones was Per a 1. Sequence homology searches showed that Per a 1 was homologous to 5 previously reported, but unidentified, sequences from B germanica and P americana . These sequences encoded proteins with multiple molecular sizes containing approximately 100 amino acid repeats. The Per a 1 sequence also showed 31% identity to a mosquito precursor protein, ANG12, which may be involved in digestion. The Per a 1 cDNA was expressed in Pichia pastoris to produce purified recombinant allergen (yield, 14 mg/L). Conclusion: The results define the molecular structure and antigenic relationships between a new family of cross-reactive "Group 1" allergens produced by both P americana and B germanica . These recombinant allergens and specific mAbs will provide tools to improve the diagnosis and treatment of allergic diseases caused by cockroaches. (J Allergy Clin Immunol 1999;103:859-64.)