IgE-binding trypsin inhibitors in plant pollen extracts

In an attempt to access the possible role of protease-antiprotease mechanisms of non-immune defence in pollinosis, only low levels of trypsin-, kallikrein- or plasmin-like proteinases could be detected in aqueous pollen extracts. In contrast, several pollen species displayed appreciable trypsin inhibitory activity, e.g. Parietaria, Olea, Ambrosia, Rumex, Chenopodium, Holcus and Poa spp. These proteins of the serpin family of anti-proteinases were found to bind specific IgE-antibodies from the serum of hay fever patients. As examples, the IgE-binding trypsin inhibitors from the pollen of Parietaria judaica and Ambrosia elatior were purified and characterized as acidic proteins with pI 4.2 and a molecular weight of 20-24 kDa.