[Allergy and lectins: action between IgE-mediated histamine release and glycoproteins from Viscum album L. (mistletoe)].

Low-molecular constituents from Viscum album (toxic) release, in irritatively toxic manner, histamine from human leukocytes without destroying the cells (cytotox test). This histamine release is prevented by preincubation with viscum lectins. The viscum lectin blocks the Fc-portion of allergen-specific IgE against anti-IgE [125I]. Lectin also inhibits the allergen-specific histamine release from human leukocytes occurring through IgE; this can be demonstrated on leukocytes from patients with atopic extrinsic asthma. The inhibitory effect of lectin could also be due to a primary membrane effect, in addition to blockage of IgE.