Haemolytic complement consumption by Parietaria pollen extracts in relation to peptide-bound flavonoids

Inhaled allergens from house dust, mites or animal danders activate human complement in vitro by engaging the C1-component through a non-antibody-dependent mechanism. These earlier findings are extended by showing that the allergenic components in extracts of Parietaria pollen are almost equally potent complement activators as those from house dust or mites. Spectroscopic evidence indicates that haemolytic complement consumption by the Parietaria allergens and their enzymic fragments is most likely related to post-translational side-chains comprising flavonoid derivatives. These adsorbed and/or peptide-bound tannin-like structures may also explain the exceptional stability of the high- and low-molecular mass allergenic components in Parietaria pollen extracts. Received 12 November 1996; received after revision 12 December 1996; accepted 17 December 1996