Human IgE binding and in vitro digestion of S-OVA.

S-OVA, a more thermostable form of ovalbumin (OVA), was formed from native OVA or egg white in vitro, by heating at high pH, and by storage at low temperatures. S-OVA showed a much lower reactivity against IgE than OVA, although this difference in IgE binding was minimized after simulated gastro intestinal digestion, despite S-OVA was more resistant to proteolysis, particularly to pepsin, than its native form. It is, therefore, likely that the transformation of OVA to S-OVA does not affect its ability to sensitise or trigger allergic reactions at the duodenal level. These results are discussed in the light of the described conformational changes reported to occur in the transition between OVA and S-OVA.