Cloning and Expression of Ama r 1, as a Novel Allergen of Amaranthus retroflexus Pollen

Abstract

Sensitisation to Amaranthus retroflexus pollen is very common in tropical and subtropical countries. In this study we aimed to produce a recombinant allergenic Ole e 1-like protein from the pollen of this weed. To predict cross-reactivity of this allergen (Ama r 1) with other members of the Ole e 1-like protein family, the nucleotide sequence homology of the Ama r 1 was investigated. The expression of Ama r 1 in Escherichia coli was performed by using a pET-21b(+) vector. The IgE-binding potential of recombinant Ama r 1 (rAma r 1) was evaluated by immunodetection and inhibition assays using 26 patients' sera sensitised to A. retroflexus pollen. The coding sequence of the Ama r 1 cDNA indicated an open reading frame of 507 bp encoding for 168 amino acid residues which belonged to the Ole e 1-like protein family. Of the 26 serum samples, 10 (38.46%) had significant specific IgE levels for rAma r 1. Immunodetection and inhibition assays revealed that the purified rAma r 1 might be the same as that in the crude extract. Ama r 1, the second allergen from the A. retroflexus pollen, was identified as a member of the family of Ole e 1-like protein.

EAACIMolecular Allergology User's Guide 2.0

“…681 So far, two allergens have been identified and designated Ama r 1 (Ole e 1-like protein) and Ama r 2 (profilin). 585,1714 Salsola kali allergy, as determined by specific sensitization to Sal k 1, the major Salsola allergen absent in Chenopodiaceae species, is overall the third cause of pollinosis in Spain and a dominant pollen allergen in the South East region. 667 In some of the drier areas of the south, up to 80% of the patients suffering from seasonal allergy are sensitized to Sal k 1, and are frequently mono-sensitized.…”

“…The ornamental plant Amaranthus retroflexus is also described as a major trigger of allergic reactions in Iran, with a sensitization frequency of 69% among allergic patients 681 . So far, two allergens have been identified and designated Ama r 1 (Ole e 1‐like protein) and Ama r 2 (profilin) 585,1714 . Salsola kali allergy, as determined by specific sensitization to Sal k 1, the major Salsola allergen absent in Chenopodiaceae species, is overall the third cause of pollinosis in Spain and a dominant pollen allergen in the…”

Analysis of different signal peptides for the secretory production of Ama r 2 in gram-positive systems (Lactococcus lactis)

“…Amaranthaceae family, short-lived plants, grow in different countries with dry climate such as Iran, Kuwait, India, the Mediterranean area and Saudi Arabia [1][2][3][4]. Amaranthus retroflexus is a native and well-known species in this family whose pollen can play a major role in seasonal respiratory allergy among the people who live in the regions with such climatic conditions [4].…”

“…Protein profile characterization of crude A. retroflexus extract revealed different components ranging from 10 to 85 kDa with main IgE-reactive bands at 10,15,18,25,39,45,50,66, and 85 kDa [1,3,4]. According to the published literature, Ama r 2 is one of the two identified allergens of A. retroflexus pollen, including Ama r 1 [2] and Ama r 3 [1]. [6] designated and reported Ama r 2 with a molecular weight of14.2 kDa as the first allergen from A. retroflexus pollen [3].…”

“…The use of prokaryote systems, in particular gram-negative strains (e.g. E. coli), as a tool has been investigated in the production of several recombinant allergens (Table 1) [1][2][3]. Recently, several efforts have been made to assess the potential of gram-positive strains such as lactic acid bacteria (LAB) for new applications in the production of heterologous proteins [11][12][13][14].…”