Immunomodulating ability of galactoside-specific lectin standardized and depleted mistletoe extract

Commercially available mistletoe extract standardized for the galactoside-specific lectin (ML-1; Eurixor) and a chromatographically ML-1-depleted preparation (same charge no. and composition of remaining components) were tested for their immunomodulating potency. In BALB/c-mice, regular subcutaneous administration of the optimal immunomodulating dosage (1 ng ML-1/kg body weight) could be shown to induce no influence on spleen weight, a non-significant increase of thymus weight, a significant increase of thymocyte, peritoneal macrophage, peripheral blood leukocyte, lymphocyte and monocyte and monocyte counts, and a significant decrease of peripheral blood granulocyte counts. Administration of analogue volumes (concentrations) of ML-1-depleted extract, however, did not induce any immunopotentiation. Accordingly, it may be assumed, that the galactoside-specific lectin (ML-1) represents the main immunomodulating component in commercially available mistletoe extracts.