D1.200 - Allergenicity of profilin isoallergens from Korean melon

Pollen food allergy syndrome (PFAS) is a common condition in which proteins from certain fruits, vegetables, and nuts cross-react with pollen allergens. Korean melon (Cucumis melo var. makuwa) is a frequent cause of PFAS. However, its allergens have not been characterized. This study aimed to characterize the allergens responsible for PFAS in Korean melon and investigate potential differences in allergenic profiles among melon cultivars.

Allergen extracts from Korean melon and other melon cultivars were analyzed using proteomic and transcriptomic approaches. Profilin isoallergens (Cuc m 2.0102 and Cuc m 2.0201) were expressed recombinantly, and IgE reactivity was assessed by ELISA and immunoblotting. Profilin content in melon extracts was quantified using targeted mass spectrometry.

Three allergenic molecules (~60, 15, and 12 kDa) were identified in melon extracts, with profilin (Cuc m 2) being the only allergen characterized by proteomic analysis. Two profilin isoallergens, Cuc m 2.0102 and Cuc m 2.0201, were identified, with Cuc m 2.0102 showing the highest identity to the canonical Cuc m 2.0101. Profilin was found to be less abundant in Korean melon compared to other cultivars like honeydew melon and Hami melon, and did not dominate IgE reactivity. Inhibition assays suggested that profilin is not the dominant allergen for Korean melon allergy patients. However, cucumisin (Cuc m 1) sensitization may indicate primary sensitization to Korean melon.

Profilin isoallergens Cuc m 2.0102 and 2.0201 were identified as key allergens in Korean melon responsible for PFAS. The profilin content varied across melon cultivars, indicating differing allergenic potential. These findings contribute to the understanding of PFAS and may help in the development of improved diagnostic tools and allergen avoidance strategies for affected individuals.