[Studies on the effect of mistletoe extract on the chemotactic activity and on chemiluminescence of polymorphonuclear leukocytes in vitro].

In the present study, the chemotactic activity of human polymorphonuclear granulocytes was measured using the tripeptide N-F-Met-Leu-Phe and different concentrations of extracts of Viscum album as chemotactic stimuli. It turned out that the extracts have the capability of stimulating chemotaxis up to 30% of the formylated tripeptide. Incubation of isolated granulocytes for 20 minutes in medium alone prior to assessment of chemotaxis results in a 20% loss of chemotactic activity as compared to the freshly isolated cells. Incubation in a medium containing the mistletoe extract does not result in partial deactivation of chemotaxis. This protective effect of the plant extract can be interpreted on the basis of an interaction with the oxidative metabolism of the granulocytes causing partial self-deactivation of chemotaxis. Interference of the extract of Viscum album with the oxidative metabolism of phagocytes is shown in experiments with luminol enhanced chemiluminescence stimulated by opsonized zymosan. The data show a dose-dependent decline of photon emission in the presence of the extracts. The in vitro data measured in the present study provide additional evidence of an immunomodulatory effect of extracts of Viscum album from which in vivo therapeutic effects can be expected.