Genetic engineering of the major timothy grass pollen allergen, Phl p 6, to reduce allergenic activity and preserve immunogenicity

Susanne Vrtala, Margarete Focke, Jolanta Kopec, Petra Verdino, Arnulf Hartl, Wolfgang R. Sperr, Alexander A. Fedorov, Tanja Ball, Steve Almo, Peter Valent, Josef Thalhamer, Walter Keller, Rudolf Valenta

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


On the basis of IgE epitope mapping data, we have produced three allergen fragments comprising aa 1-33, 1-57, and 31-110 of the major timothy grass pollen allergen Phl p 6 aa 1-110 by expression in Escherichia coli and chemical synthesis. Circular dichroism analysis showed that the purified fragments lack the typical α-helical fold of the complete allergen. Superposition of the sequences of the fragments onto the three-dimensional allergen structure indicated that the removal of only one of the four helices had led to the destabilization of the α helical structure of Phl p 6. The lack of structural fold was accompanied by a strong reduction of IgE reactivity and allergenic activity of the three fragments as determined by basophil histamine release in allergic patients. Each of the three Phl p 6 fragments adsorbed to CFA induced Phl p 6-specific IgG Abs in rabbits. However, immunization of mice with fragments adsorbed to an adjuvant allowed for human use (AluGel-S) showed that only the Phl p 6 aa 31-110 induced Phl p 6-specific IgG Abs. Anti-Phl p 6 IgG Abs induced by vaccination with Phl p 6 aa 31-110 inhibited patients' IgE reactivity to the wild-type allergen as well as Phl p 6-induced basophil degranulation. Our results are of importance for the design of hypoallergenic allergy vaccines. They show that it has to be demonstrated that the hypoallergenic derivative induces a robust IgG response in a formulation that can be used in allergic patients.

Original languageEnglish (US)
Pages (from-to)1730-1739
Number of pages10
JournalJournal of Immunology
Issue number3
StatePublished - Aug 1 2007

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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