Antioxidant pine nut protein hydrolysate as a therapeutic oral immunotherapy agent in a murine model of pine nut allergy

Abstract

Oral immunotherapy (OIT) is one of the most promising treatments for food allergy, although no protocols have yet been described for pine nut allergy. We aim to produce a pine nut protein hydrolysate to be used as a treatment agent in OIT. Hydrolysates were produced using three proteases (pepsin, trypsin, and Alcalase) alone or in combination and their antioxidant activity, antigenicity, and immunomodulatory properties were determined in vitro. Pine nut-sensitized C57BL/6 mice were subjected to OIT with intact and hydrolysed pine nut protein. The trypsin hydrolysate showed higher antioxidant activity and lower IgE binding capacity than the intact protein, and it was able to desensitize mice in a similar way to the unhydrolyzed protein. Therefore, it could be regarded as a good candidate as a therapeutic agent in OIT on the grounds of its effectiveness in desensitizing allergic mice and its improved antioxidant and immunoreactive properties with respect to intact pine nut protein. Oral immunotherapy is one of the most promising treatments for food allergy, although no protocols have yet been described for pine nut allergy. To identify pine nut protein hydrolysates with potential for OIT, we applied enzymatic hydrolysis using food-grade enzymes and a two-step selection strategy. Hydrolysates were first screened for in vitro antioxidant activity and then assessed for their ability to modulate allergen-specific T-cell responses ex vivo. The trypsin-derived hydrolysate showed the most promising profile, leading to further evaluation of its IgE-binding properties and therapeutic potential in pine nut-sensitized C57BL/6 mice subjected to OIT with intact and hydrolysed pine nut protein. Mice treated with the trypsin hydrolysate showed reduced specific IgE and IgG1 levels and were protected against oral pine nut-induced anaphylaxis, similar to those treated with intact pine nut protein. Due to its ability to desensitize allergic mice, combined with lower IgE binding and higher antioxidant activity, the trypsin-hydrolysed pine nut protein appears to be a promising candidate for OIT.