title: Molecular and immunological characterization of a novel timothy grass (Phleum pratense) pollen allergen, Phl p 11.
abstract: BACKGROUND
  Allergy to grass pollen is typically associated with serum IgE antibodies to group 1 and/or group 5 allergens, and additionally often to one or several less prominent allergens. Most of the grass pollen allergens identified to date have been characterized in detail by molecular, biochemical and immunological methods, timothy grass being one of the most thoroughly studied species. However, a 20-kDa allergen frequently recognized by IgE antibodies from grass pollen allergics has so far escaped cloning and molecular characterization.
  
  
  OBJECTIVE
  To clone and characterize the 20 kDa timothy grass pollen allergen Phl p 11.
  
  
  METHODS
  Phl p 11 cDNA was cloned by PCR techniques, utilizing N-terminal amino acid sequence obtained from the natural allergen. Phl p 11 was expressed as a soluble fusion protein in Escherichia coli, purified to homogeneity and used for serological analysis and to study Phl p 11 specific induction of histamine release from basophils and skin reactivity in sensitized and control subjects.
  
  
  RESULTS
  Phl p 11 cDNA defined an acidic polypeptide of 15.8 kDa with homology to pollen proteins from a variety of plant species and to soybean trypsin inhibitor. The sequence contained one potential site for N-linked glycosylation. Serological analysis revealed that recombinant Phl p 11 shared epitopes for human IgE antibodies with the natural protein and bound serum IgE from 32% of grass pollen-sensitized subjects (n = 184). Purified recombinant Phl p 11 elicited skin reactions and dose-dependent histamine release from basophils of sensitized subjects, but not in non-allergic controls.
  
  
  CONCLUSIONS
  As the first representative of group 11 grass pollen allergens, Phl p 11 has been cloned and produced as a recombinant protein showing allergenic activity. One-third of grass pollen-sensitized subjects showed specific IgE reactivity to recombinant Phl p 11, corresponding in magnitude to a significant proportion of specific IgE to grass pollen extract.
authors.affiliation: Pharmacia Diagnostics AB, Uppsala, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Marknell DeWitt
authors.forename: V
authors.initials: V
authors.lastname: Niederberger
authors.forename: P
authors.initials: P
authors.lastname: Lehtonen
authors.forename: S
authors.initials: S
authors.lastname: Spitzauer
authors.forename: W R
authors.initials: WR
authors.lastname: Sperr
authors.forename: P
authors.initials: P
authors.lastname: Valent
authors.forename: R
authors.initials: R
authors.lastname: Valenta
authors.forename: J
authors.initials: J
authors.lastname: Lidholm
mesh_terms: D000595:Amino Acid Sequence; D000937:Antigen-Antibody Reactions; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000276:immunology; D006098:Granulocytes / Q000276:immunology; D006636:Histamine Release; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D008969:Molecular Sequence Data; D031784:Phleum / Q000276:immunology*; D011058:Pollen; D016133:Polymerase Chain Reaction / Q000379:methods; D011994:Recombinant Proteins / Q000276:immunology; D017422:Sequence Analysis, DNA; D012882:Skin Tests
chemical_list: D018797:Cell Cycle Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E