A New Allergen from Ragweed (Ambrosia artemisiifolia) with Homology to Art v 1 from Mugwort

Abstract

Art v 1, the major pollen allergen of the composite plant mugwort (Artemisia vulgaris) has been identified recently as a thionin-like protein with a bulky arabinogalactan-protein moiety. A close relative of mugwort, ragweed (Ambrosia artemisiifolia) is an important allergen source in North America, and, since 1990, ragweed has become a growing health concern in Europe as well. Weed pollen-sensitized patients demonstrated IgE reactivity to a ragweed pollen protein of apparently 29 -31 kDa. This reaction could be inhibited by the mugwort allergen Art v 1. The purified ragweed pollen protein consisted of a 57-amino acidlong defensin-like domain with high homology to Art v 1 and a C-terminal proline-rich domain. This part contained hydroxyproline-linked arabinogalactan chains with one galactose and 5 to 20 and more ␣-arabinofuranosyl residues with some ␤-arabinoses in terminal positions as revealed by high field NMR. The ragweed protein contained only small amounts of the single hydroxyproline-linked ␤-arabinosyl residues, which form an important IgE binding determinant in Art v 1. cDNA clones for this protein were obtained from ragweed flowers. Immunological characterization revealed that the recombinant ragweed protein reacted with >30% of the weed pollen allergic patients. Therefore, this protein from ragweed pollen constitutes a novel important ragweed allergen and has been designated Amb a 4.The pollen of common ragweed (Ambrosia artemisiifolia) is a major cause of hay fever and associated asthma in Northern America. During the past few decades, ragweed has started to spread in many parts of central Europe, where it has become a serious health problem in the sensitized population. Several initiatives have formed to prevent further spread in e.g. France, Austria or southern Germany. The Compositae (or Asteraceae) family is one of the largest families of flowering plants, but only a few are important allergenic sources. These include Ambrosia (ragweed), Artemisia (mugwort), Helianthus (sunflower), and Parthenium (feverfew). It was further demonstrated that sera of mugwort allergic patients show considerable cross-reactivity with ragweed pollen extracts (1, 2). IgE-binding to mugwort allergens in immunoblots was inhibited effectively by ragweed pollen extract (1), which indicates close homology of the essential allergens in ragweed and mugwort pollen. So far, six groups of allergens have been identified in ragweed pollen. Most patients were classified as ragweed allergic if they reacted with the pectate lyases of the Amb a 1/2 group (3, 4). The homologous pectate lyase Art v 6 in mugwort has been reported to play only a minor role in allergic disease. Amb a 6 (lipid transfer protein), Amb a 8 (profilin), Amb a 9 and Amb a 10 (both calcium-binding proteins) are small proteins belonging to the group of well known cross-reactive pan-allergens (1, 4 -8). Amb a 7 and the fragment Amb a 3 are plastocyanins and are described only as minor ragweed allergens (9).In mugwort pollen, the major allergen is Art v 1, a protein w...

Characterization of the Arabinogalactan Protein 31 (AGP31) of Arabidopsis thaliana

“…Interestingly, Tryfona et al (49) carried out an alternative approach to elucidate the structure of native wheat flour AGP, combining AG enzymatic digestion and product analysis using polysaccharide analysis by carbohydrate gel electrophoresis and MS. Note that type III AGs have also been described in Art v 1 and Amb a allergens, which have Pro-rich domains (50,51).…”

A Molecular Diagnostic Algorithm to Guide Pollen Immunotherapy in Southern Europe: Towards Component-Resolved Management of Allergic Diseases

“…Importantly, it is an effective marker of genuine sensitization to mugwort pollen, even when cross-reactivity to minor ragweed allergen Amb v 4 occurs [61]. Furthermore, when major allergen quantification is involved in the process of mugwort pollen extract standardization, Art v 1 is typically used, suggesting a potential increase in SIT efficacy in anti-Art v 1-IgE-positive patients [12].…”

Clinical Relevance of IgE to Profilin and/or Polcalcin in Pollen-Sensitized Patients

“…Major allergens are considered to be the relevant trigger of allergic symptoms in patients [5]. Such major allergens are Bet v 1 (birch), Phl p 1 and 5 (timothy grass), Art v 1 (mugwort plant) and Ole e 1 (olive tree), which is highly homologous to Fra e 1 (ash tree), respectively [6,7,8,9]. Some minor allergens are widespread in pollens from different plants and are, therefore, called panallergens.…”