Effect of Heat-Induced Aggregation on the IgE Binding of Patatin (Sol t 1) Is Dominated by Other Potato Proteins

Abstract

The interaction of the major potato allergen patatin, Sol t 1, with IgE was investigated on a quantitative level as a function of heat treatment at different temperatures. On the basis of a number of publications, potato is considered to be a heat-labile allergen, but the molecular explanation for this behavior was not given. In this work, heat treatment of patatin in the absence and presence of other potato proteins mimicking the proteinaceous environment of the potato was studied. Using far-UV circular dichrosim spectroscopy, tryptophan fluorescence spectroscopy, and differential scanning calorimetry, the molecular transitions during heating of patatin were investigated. It was found that as long as patatin is not aggregated, denaturation of patatin on a secondary or tertiairy folding level is reversible with only a minor effect on the IgE affinity. Aggregation of patatin results in a nonreversible unfolding and a concomitant important decrease in affinity for IgE (25-fold). Aggregation of patatin in the presence of other potato proteins results in a less condensed aggregate compared to the situation of isolated patatin, resulting in a more pronounced decrease of affinity for IgE (110-fold). It is concluded that the heat lability of patatin-IgE interaction is explained by aggregation of patatin with other potato proteins rather than by denaturation of patatin itself.

Heat denaturation, a simple method to improve the immunotherapeutic potential of allergens

“…This was previously reported for other allergens [25,26,32] and fits well with the clinical observations that allergic individuals usually tolerate cooked food better than raw food [25]. We also found that heat-denatured allergens showed a lower potential to sensitise mice.…”

“…Heat-denaturation is well known to reduce the reactogenicity of allergens with IgE, as cooked foods are usually well or better tolerated by allergic individuals [24][25][26]. In this study, we tested whether this very simple strategy to reduce the reactogenicity of allergens might be useful for SIT, by investigating the effect of heat-denaturation on reactogenicity versus immunogenicity of several frequently used allergens.…”

“…One strategy is to replace the currently used aluminium salts, which have Th2-polarizing properties, with novel adjuvants such as Tolllike receptor ligands [6,7] that trigger Th1 responses. Another strategy is to increase safety and tolerability of SIT by injecting the allergen in a form that is not recognised by IgE, such as naked DNA vaccines Heat-denaturation is well known to reduce the reactogenicity of allergens with IgE, as cooked foods are usually well or better tolerated by allergic individuals [24][25][26]. In this study, we tested whether this very simple strategy to reduce the reactogenicity of allergens might be useful for SIT, by investigating the effect of heat-denaturation on reactogenicity versus immunogenicity of several frequently used allergens.…”

Heat denaturation affects the ProDer p 1 IgE reactivity and downregulates the development of the specific allergic response☆

“…The allergen polymerization into high molecular weight molecules was previously observed with heat-treated Der f 2, 27 ovalbumin, 26,28 Sol t 1, 24 and Ara h 1. 29 By attenuated total reflectanceeFourier transform infrared spectroscopy, we demonstrated that thermally induced ProDer p 1 aggregation is associated with transformation of a-helical into b-sheet structures (data not shown).…”

Aspects of food processing and its effect on allergen structure

“…However, some allergens may be thermostable like the major peanut allergen Ara h 1, such that the IgE-reactive conformational epitopes are resistant to heat-induced denaturation, as shown by Koppleman and coworkers [9] for roasting peanuts. In some cases, heat-treatment causes protein denaturation, followed by spontaneous renaturation during cooling, as reported for the potato allergen patatin 8Sol t 1) [10], which also appear to form aggregates with other potato proteins during thermal processing. Food proteins also undergo chemical interactions with other food components, such as amino acids with sugars.…”