Isolation and characterization of two cDNA clones coding for isoforms of the Parietaria judaica major allergen Par j 1.0101.
Two cDNA clones named P9* and P1* of 794 and 631 bp, respectively, were isolated from a lambda ZAP cDNA expression library using Parietaria judaica (Pj) pollen-specific IgE antibodies from a pool of sera (n = 23) of patients allergic to Pj. Sequence analysis showed open reading frames of 176 and 138 amino acids. Both clones contain a putative signal peptide giving two mature processed proteins named Par j 1.0102 of 14,726 D and Par j 1.0201 of 10,677 D. These proteins represent isoallergenic forms of the major Pj allergen Par j 1.0101 (clone P5) previously reported. The Par j 1.0102 shared 98% amino acid sequence homology with the P5, while the Par j 1.0201 shared 89% homology. Since P1, P5 and P9 clones were expressed in Escherichia coli, and since the three allergenic proteins shared a very high degree of sequence identity and comparable binding to the Pj-specific IgE, we decided to analyze in more detail the immunological properties of only one allergen, the recombinant Par j 1.0101. The allergenic activity determined by the histamine release assay ranged between 9 and 56%, depending on the allergic patient analyzed, while it blocked approximately 40% of all the Pj-specific IgE antibodies, as detected after ELISA and cross-absorption analysis.
Duro
G
G
Instituto di Biologia dello Sviluppo, CNR, Palermo, Italia.
Colombo
P
P
Assunta Costa
M
M
Izzo
V
V
Porcasi
R
R
Di Fiore
R
R
Locorotondo
G
G
Cocchiara
R
R
Geraci
D
D
D000485:Allergens / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000941:Antigens / Q000737:chemistry / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007536:Isomerism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D011058:Pollen / Q000737:chemistry* / Q000276:immunology*
D000485:Allergens; D000941:Antigens; D018076:DNA, Complementary; C105336:PMAI protein, Parietaria judaica; D010940:Plant Proteins