Thionins from Viscum album L: influence of the viscotoxins on the activation of granulocytes.
BACKGROUND
Extracts from European mistletoe (Viscum album L.) are applied in adjuvant cancer treatment, and some components, especially the mistletoe lectins (ML) have been immunologically characterised, but not the thionins, termed viscotoxins (VT).


METHODS
The influence of the VT on human granulocytes was studied by flow cytometry: E.coli co-stimulated respiratory burst by oxidation of dihydrorhodamine 123 to rhodamine 123 and phagocytosis by ingestion of FITC-labelled E.coli.


RESULTS
VT (25 and 250 micrograms/ml), in contrast to ML, significantly enhanced phagocytosis and burst activity. VT-rich mistletoe extracts also exerted significant effects. In addition, E.coli-activated granulocytes positively stain with Annexin-V and propidium iodide only due to 250 micrograms/ml VT incubation, suggesting that at this concentration burst activity was induced by the physiological activity of granulocytes after microbial ingestion and also by cytotoxic effects.


CONCLUSIONS
Viscotoxins exert yet unknown strong immunomodulatory effects on human granulocytes, which might be of benefit for tumour patients, in addition to their cytotoxic properties.
Stein
G M
GM
University Witten/Herdecke, Department of Applied Immunology, Communal Hospital, Germany. stein.g@primus-online.de
Schaller
G
G
Pfüller
U
U
Schietzel
M
M
Büssing
A
A
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D006098:Granulocytes / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D010587:Phagocytosis / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D028321:Plant Preparations; D010940:Plant Proteins; D016897:Respiratory Burst / Q000187:drug effects; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological / Q000494:pharmacology*
D000276:Adjuvants, Immunologic; D010936:Plant Extracts; D028321:Plant Preparations; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum; C488038:viscotoxin