Profilins constitute a novel family of functional plant pan-allergens.

Abstract

Sllmmal~Type I allergy is a major health problem in industrialized countries where up to 15% of the population suffer from allergic symptoms (rhinitis, conjunctivitis, and asthma). Previously, we identified a cDNA clone that encoded a birch pollen allergen as profilin. Profilins constitute a ubiquitous family of proteins that control actin polymerization in eukaryotic cells; in particular, profilin participates in the acrosomal reaction of animal sperm cells. Although profilins had been unknown in plants so far, our finding led to the assumption that profilins might have similar functions in pollens during plant fertilization and therefore represent allergenic components in almost all pollens. We show that profilins are prominent allergens that can be isolated from tree pollens (Betula verrucosa, birch), from pollens of grasses (Phleum pratense, timothy grass), and weeds (Artemisia vulgaris, mugwort). About 20% of all pollen allergic patients tested (n = 65) displayed immunoglobulin E (IgE) reactivity to recombinant birch prolilin that was expressed in pKK223-3. An IgE inhibition experiment performed with recombinant birch profilin and purified natural profilins from timothy grass and mugwort indicates common IgE epitopes. Moreover, all pollen profilins purified from these far distantly related plant species, and likewise the purified recombinant birch profilin, are able to elicit dose-dependent histamine release via high affinity Fce receptor of blood basophils from profilin allergic patients. The presence of profdin and possibly related proteins as crossreacting allergenic components in various plants therefore provides an explanation as to why certain allergic patients display type I allergic reactions with pollens and even food from distantly related plants. A functional pan-allergen, like profilin, available as purified recombinant protein, may be a useful diagnostic and probably therapeutic reagent.

Sensitization to profilin in the Central region of Portugal

“…These findings agree with the current understanding of profilin as a plant panallergen (Valenta et al, 1992;Radauer et al, 2006;Ebner et al, 1995).…”

“…Sensitization to profilin was 21.0% of all pollen sensitized individuals. This percentage is similar to that observed by Valenta et al (1992) in their first report of profilin as a plant panallergen (20%) and by Pauli et al (1996) using rBetv2 for SPT (19.6%). However Asero et al (2008) found a higher proportion of sensitization to date palm profilin (30%) in patients sensitized to pollens.…”

“…Several studies report a high prevalence of sensitization to different pollen species belonging to taxonomically distant families (Valenta et al, 1992;Mari, 2001). This can be explained by sensitization to panallergens present in pollens, namely profilins and calcium-binding proteins (Valenta et al, 1991(Valenta et al, , 1992(Valenta et al, , 1998Radauer et al, 2006;Ebner et al, 1995).…”

“…This can be explained by sensitization to panallergens present in pollens, namely profilins and calcium-binding proteins (Valenta et al, 1991(Valenta et al, , 1992(Valenta et al, , 1998Radauer et al, 2006;Ebner et al, 1995).…”

“…Profilins from pollen and plant foods, are highly crossreactive and elicit IgE responses in 10-30% of pollen-allergic patients (Valenta et al, 1992;Asero et al, 2008). They may be responsible for several pollen-food allergy syndromes (Egger et al, 2006).…”