Kiwifruit as a food allergen source

Abstract

Since its first appearance on the market, kiwifruit has become very popular in the human diet due to its pleasant taste, low caloric value and high content of vitamin C. However, kiwifruit allergy has become a frequent cause of type I hypersensitivity in the western society. The molecular basis for kiwifruit allergy has been ascribed to up-to-now 11 identified IgE reactive molecules. They are proteins and glycoproteins with a molecular mass between 10 and 50 kDa. The major kiwifruit allergen is a cysteine protease denoted as Act d 1, which represents 50 % of the soluble protein extract. Due to differences in the abundance of the protein components and biological activity, the quality of kiwifruit extracts intended for allergy diagnosis can vary in content and amount of IgE reactive molecules. In addition, the quality of allergen extracts for allergy diagnosis depends on the fruit ripening stage and storage conditions. In terms of clinical reactivity, it has become evident that kiwifruit allergy is not a homogeneous disorder. Different patterns of IgE reactivity accompany several clinical subgroups that have been identified in different geographical regions. In the last decade, enormous progress has been made in the isolation and characterization of kiwifruit allergens. This paper presents an overview of the structural features of kiwifruit allergens.

Od prvog pojavljivanja na tržištu plod kivija je postao izuzetno popularan sastojak humane ishrane usled prijatnog ukusa, niske kalorijske vrednosti i visokog sadržaja vitamina C. Međutim, alergija na kivi je postala učestali uzrok preosetljivosti tipa I u zapadnom društvu. Do sada je otkriveno 11 IgE vezujućih molekula koji čine molekulsku osnovu alergije na kivi. To su proteini i glikoproteini molekulskih masa između 10 i 50 kDa. Glavni alergen kivija je cistein-proteaza označena kao Act d 1, koja sačinjava 50 % rastvornih proteina ploda kivija. Usled razlike u zastupljenosti proteinskih komponenti i biološkoj aktivnosti, kvalitet proteinskih ekstrakata kivija koji se upotrebljavaju u dijagnostifikovanju alergije može varirati u sadržaju i količini IgE reaktivnih molekula. Takođe, kvalitet alergenih ekstrakata zavisi od stepena zrelosti voća prilikom branja, kao i od uslova skladištenja voća nakon branja. Po pitanju kliničke reaktivnosti postalo je očigledno da alergija na plod kivija ne predstavlja homogeni poremećaj. Različiti obrasci IgE reaktivnosti uočeni su kod nekolicine kliničkih podgrupa koje su identifikovane u različitim geografskim regijama. Tokom poslednje decenije načinjen je veliki napredak u izolovanju i karakterizaciji IgE vezujućih proteina kivija. U okviru ovog rada daćemo pregled strukturnih osobina alergenih proteina kivija.