title: Molecular cloning, expression and immunological characterisation of Pas n 1, the major allergen of Bahia grass Paspalum notatum pollen.
abstract: Bahia grass, Paspalum notatum, is a clinically important subtropical grass with a prolonged pollination season from spring to autumn. We aimed to clone and characterise the major Bahia grass pollen allergen, Pas n 1. Grass pollen-allergic patients presenting to a tertiary hospital allergy clinic were tested for IgE reactivity with Bahia grass pollen extract by skin prick testing, ImmunoCAP, ELISA and immunoblotting. Using primers deduced from the N-terminal peptide sequence of a group 1 allergen of Bahia grass pollen extract separated by two-dimensional gel electrophoresis, the complete Pas n 1 cDNA was obtained by rapid amplification of cDNA ends and cloned. Biological relevance of recombinant Pas n 1 expressed in Escherichia coli was assessed by serum IgE reactivity and basophil activation. Twenty-nine of 34 (85%) consecutive patients presenting with grass pollen allergy were skin prick test positive to Bahia grass pollen. The Pas n 1 cDNA has sequence homology with the beta-expansin 1 glycoprotein family and is more closely related to the maize pollen group 1 allergen (85% identity) than to ryegrass Lol p 1 or Timothy grass Phl p 1 (64 and 66% identity, respectively). rPas n 1 reacted with serum IgE in 47 of 55 (85%) Bahia grass pollen-allergic patients, activated basophils and inhibited serum IgE reactivity with the 29 kDa band of Bahia grass pollen extract. In conclusion the cDNA for the major group 1 allergen of the subtropical Bahia grass pollen, Pas n 1, was identified and cloned. rPas n 1 is immunologically active and is a valuable reagent for diagnosis and specific immunotherapy of grass pollen allergy.
authors.affiliation: CRC for Asthma and Airways, K25-Medical Foundation Building, University of Sydney, Sydney, NSW 2006, Australia. j.davies2@uq.edu.au
authors.forename: Janet M
authors.initials: JM
authors.lastname: Davies
authors.forename: Diana
authors.initials: D
authors.lastname: Mittag
authors.forename: Thanh D
authors.initials: TD
authors.lastname: Dang
authors.forename: Karen
authors.initials: K
authors.lastname: Symons
authors.forename: Astrid
authors.initials: A
authors.lastname: Voskamp
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Rolland
authors.forename: Robyn E
authors.initials: RE
authors.lastname: O'Hehir
mesh_terms: D000485:Allergens / Q000235:genetics* / Q000276:immunology*; D001249:Asthma / Q000276:immunology; D001483:Base Sequence; D001491:Basophils / Q000276:immunology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000276:immunology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008969:Molecular Sequence Data; D031781:Paspalum / Q000235:genetics* / Q000276:immunology*; D010940:Plant Proteins / Q000235:genetics* / Q000276:immunology*; D011058:Pollen / Q000235:genetics* / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology; D012882:Skin Tests
chemical_list: D000485:Allergens; D018076:DNA, Complementary; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E