DOSE-DEPENDENT IMMUNOACTIVE EFFECTS OF MI STLETOE LECTIN-1

Galactoside-specific mistletoe lectin-1 (ML-1) was isolated by affinit y chromatography from proprietary mistletoe extract and checked in BAL B/c mice for its immunoactive potency. To investigated the optimal imm uno-modulating dosage, ML-1 (0.5, 1.0, 2.5, 5.0 ng/kg body weight, b.w .) was subcutaneously administered for three subsequent days followed by another injection of 1 ng ML-1/kg b.w. induced optimal immunomodula tion, since thymocyte proliferation, maturation and emigration were si gnificantly enhanced in this murine model as compared to non-treated c ontrol mice. Furtheron, counts of peripheral blood lymphocytes and mon ocytes as well as expression of relevant activation markers on these c ells revealed significant increases after ML-1 (1 ng/kg b.w.) administ ration. However, increase of cell counts and activity of peritoneal ma crophages were less pronounced but still statistically significant for this ML-1 concentration. Determination of immune responses after low dose ML-1 treatment (0.5 ng/kg b.w.) presented relevant (partly statis tically significant) increases, too. However, high dose ML-1 treatment (2.5, 5.0 ng/kg/ b.w.) did not enhance (but suppress) relevant immune functions. For future clinical/therapeutical treatment strategies, ML -1 dosages ranging from 0.5-1.0 ng/kg b.w. may be supposed to be optim al.