Hev b 8, the Hevea brasiliensis latex profilin, is a cross-reactive allergen of latex, plant foods and pollen

Background: Plant profilins are important pan-allergens. They are responsib le for a significant percentage of pollen-related allergies. Limited inform ation is available about their involvement in the latex-fruit syndrome and the cross-reactivities between latex and pollen. We aimed to clone and expr ess the Hevea brasiliensis latex profilin to investigate its allergological significance and serological cross-reactivities to profilins from plant fo ods and pollens. Methods: A DNA complementary to messenger RNA (cDNA) codin g for the Hevea latex profilin, Hev b 8, was amplified by polymerase chain reaction from latex RNA. Recombinant (r)Hev b 8 was produced in Escherichia coli and used to screen sera from 50 latex- allergic health care workers ( HCWs) with well-documented histories of food and pollen allergy and 34 late x-allergic Spina bifida (SB) patients. The cross-reactivity of natural Hev b 8 and rHev b 8 with other plant profilins was determined by ELISA inhibit ion assays. A three-dimensional homology model of Hev b 8 was constructed b ased on known profilin structures. Results:The cDNA of Hev b 8 encoded a pr otein of 131 amino acids with a predicted molecular mass of 14 kD. Twelve o f the 50 HCWs and 2 of the 34 SB patients were sensitized to Hev b 8. All H ev b 8-sensitized patients showed allergic symptoms to pollen or plant food s. Cross-reactivities between profilins of latex, pollen and plant food wer e illustrated by their ability to inhibit IgE binding to rHev b 8. Homology modeling of Hev b 8 yielded a structure highly similar to Bet v 2,the birc h pollen profilin,with the most distinct differences located at the N-termi nus. Conclusions: We conclude that primary sensitization to latex profilin in the majority of cases takes place via pollen or food profilins. Addition ally, pollinosis and food-allergic patients with profilin-specific IgE can be at risk of developing latex allergy. Copyright (C) 2001 S. Karger AG, Ba sel.